Explore the V Beam Antenna on the ANTENNAS page at Antenna University-an Education Center dedicated to practical STEM learning. This guide introduces the V-beam’s traveling-wave radiation concept, key performance traits, and real-world applications for HF directional communication, with clear explanations that support students, hobbyists, and working professionals. https://www.k0uo.com/post/v-beams-hf-wire-antenna-veebeam
The Rhombic antenna array was designed in 1931 by Ed Bruce and Harald Friis It was commonly used in the HF shortwave point to point and broadcast as a broadband directional antenna, it is also known as a diamond antenna. See 1931 patent, US 2285565A1 I (aktuellum.com) There are two primary types of Rhombic antennas that are widely recognized in the field of radio frequency communications: The resonant Rhombic antenna and the terminated Rhombic antenna. Each of these antenna types has unique characteristics and applications that make them suitable for different scenarios in wireless communication. And I use a third type, which will be discussed later in this post which is highly efficient (90%). Resonant Rhombic Antenna The resonant Rhombic antenna is characterized by its bidirectional radiation pattern. This means that it can effectively transmit and receive signals in two opposite directions, making it an excellent choice for applications where communication is required over long distances and in both directions. The design of the resonant Rhombic antenna typically consists of four wire elements arranged in a diamond shape, which allows for efficient signal propagation. One of the key features of the resonant Rhombic antenna is its ability to operate at a specific frequency range, which is determined by its dimensions. The antenna is designed to resonate at a particular frequency, ensuring that it can efficiently transmit and receive signals within that frequency band. This resonant behavior not only enhances the antenna's performance but also helps to minimize signal loss, making it a preferred option for high-frequency applications, such as shortwave radio communications. In addition to its bidirectional capabilities, the resonant Rhombic antenna is also known for its very high gain and low noise RX characteristics. This makes it suitable for applications that require clear and reliable communication over considerable distances, such as in amateur radio, broadcasting, or in military communications. At this time K0UO is the only Rhombic station using re-phasing. These are the largest wire antennas in use by an amateur radio stations with 14 to +18 dBd of gain. Signal to noise is excellent at the Rhombic farm. So many hams that I talk to now days, ask me what is a Rhombic, and where can I buy one? Most have never heard of the classic array. However if they are U.S. hams, they should have reviewed three questions on the ham test about Rhombic arrays, the questions have been on the ham test for years. questions about the rhombic antenna has been of the FCC test pool for years until 2016 In fact, information about the Rhombic has been on U.S. FCC test pool for years Terminated Rhombic Antenna On the other hand, the terminated Rhombic antenna is designed to be unidirectional, meaning it is optimized to transmit and receive signals primarily in one direction. This directional capability is achieved by incorporating a resistive termination at the antenna's far end, which helps to absorb unwanted reflections and reduces the amount of signal that is radiated in the opposite direction. As a result, the terminated Rhombic antenna can provide a more focused and stronger signal in its intended direction, making it highly effective for point-to-point communication links. The design of the terminated Rhombic antenna also follows a similar diamond-shaped configuration, but with the addition of the termination, which plays a crucial role in its performance. The termination not only enhances the antenna's directivity but also improves its impedance matching, allowing for better energy transfer between the antenna and the transmission line. This feature is particularly beneficial in applications where minimizing interference and maximizing signal strength are paramount. While the terminated Rhombic antenna may not offer the same bidirectional capabilities as its resonant counterpart, it compensates for this by providing a more powerful signal in its designated direction. This makes it an ideal choice for applications such as broadcasting, where a strong signal is required to reach a specific audience or geographic area. In summary, the two types of Rhombic antennas—the resonant Rhombic antenna and the terminated Rhombic antenna—serve distinct purposes in the realm of radio frequency communications. The resonant Rhombic antenna, with its bidirectional capabilities, is well-suited for applications requiring two-way communication, while the terminated Rhombic antenna excels in scenarios demanding unidirectional signal transmission. Each antenna type offers unique advantages that cater to the diverse needs of communication systems, highlighting the importance of selecting the appropriate antenna based on the specific requirements of the application at hand. Generally, the antenna is terminated with a value equivalent to characteristic impedance thereby causing the non-resonant condition to be establish. Making the radiation characteristics of the antenna are unidirectional. When the power through the feed lines either the 2-wire transmission line is provided to the antenna. Then the generated current travels through the legs of the Rhombic antenna (Fast Traveling Wave). These currents flow through the antenna and generate radio waves that progress in one direction through the legs of the antenna. Now there are three types of Rhombics in use. The Third type of Rhombic is a K0UO Re-entrant I don't terminate my antennas, but use what is called, re-entrant line termination for a higher 90% efficiency, see more about that system later in this blog post. The Re-entrant Rhombic array is one of the highest forward gain HF antennas, with its 90% efficiency. Read more about this later in this post and others. traveling wave antenna just like k0uo used at the biggest ham radio station in the worlds 1200 acers. K0UO only uses the Re-entrant rhombic system that achieves 90% efficiency, by re-phasing the power back into the antenna, rather than dissipating it as heat in termination resistors. Animation illustrating the operation of a traveling wave antenna, showing the flow of current (I) and electric field (E) along the antenna, with a resistor (R) at one end to absorb wave energy, and wave propagation indicated at an angle θ. The Proper impedance matching between an antenna and its transmission line is crucial in maximizing signal efficiency and reducing unwanted reflections, which can cause major losses in RF power going to the antenna. Impedance matching keeps the impedance of the antenna and the transmission line the same in order to see the least amount of signal per watt lost. Remember there is no SWR on a traveling wave antenna. It's only the mismatching between the 600 to 800 ohm of the antenna, and the 50 ohm transmission line, that creates it. Two great books to read, Rhombic Antenna Design, by A.E. Harper of Bell Labs, and W6AM, which shows Dow Wallace’s antenna farm after WW 2 to the 1980s. phot of two bookswo great books to read, Rhombic Antenna Design, by A.E. Harper of Bell Labs, and W6AM, which shows Dow Wallace’s antenna farm after WW 2 to the 1980s. Rhombic array design for Broadcaster, DOD. Hams, Stock traders high speed nets, The Rhombic Bibles Rhombic Antennas were used in WWII Military Communications, by Harnessing the RF Power, to Win the War The key concept with traveling-wave type antennas like a Rhombic or Vee Beam (V-Beam) is that there are no standing waves, on the antenna itself, the current and voltage levels are the same everywhere along the antenna conductors,. But you still have to match it to the fed-line. The Rhombic is the largest and most refined of the HF long-wire antennas, consisting of two Vs, open-end to open-end. The result is 4 wires contributing aligned lobes for higher gain and narrower beam-width. The Rhombic suppresses unwanted side lobes better than the V antenna See SWR photo below it shows one of my antennas, now this is flat, no tuner! an Actual photo at K0UO Kansas antenna site of Low swr with high forward gain, from 160 meters up to 6 meters K0uo has the highest and largest antennas in use to day by anyone today. Always Low SWR The Rhombic antenna is a wide-band progressive traveling-wave (fast-wave) antenna, made of two acute-angle V-beams placed end-to-end and terminated in an open circuit or in a resistive load. Each side of the antenna is made of two legs of length "L" and as a whole the antenna has the shape of a rhombus, that is, the opposite angles are of the same value. The non-terminated Rhombic antenna is bi-directional, whereas the terminated Rhombic antenna is directional. The Rhombic antenna is useful over a wide frequency range. Although some changes in gain, directivity, and characteristic impedance do occur with a change in operating frequency, these changes are small enough to be neglected. A rhombic antenna design works best at a height of one-half to a full wavelength at the lowest frequency. So: K0UO has No waiting for a rotator to turn, the system has every direction, every band, every time. To be effective, an efficient station must balance performance, ergonomics, and reliability. A drawing of a rhombic swithing setup to change direction 180 degree switch layout design Diagram showing a rhombic array individual gray radiation patterns on the left and a resultant blue and gray radiation pattern on the right. Text labels included. Rhombic Radiation Patterns The Rhombic is an equilateral parallelogram shaped antenna, it has two opposite acute angles. The tilt angle, θ is approximately equal to 90° minus the angle of major lobe. Rhombic antenna works under the principle of a fast traveling wave antenna. It is setup in the form of a rhombus or diamond shape and is normally suspended horizontally above the surface of the earth, but can be made vertical. It works great for long-distance F-layer propagation due to low vertical radiation angle, however it does have some higher radiation lobes which were thought as wasted power for long point to point use however for ham radio this helps fill in closer in coverage, but overlooked in modeling and a major advantage of the antenna for ham radio use, for making more QSOs. In designing the Rhombic it has to be kept in mind that length of all the four conductive wires must be equal, ranging between one wavelength, to over four. However, the opposite acute angles of the rhombus must be equal. To avoid reflections of the traveling wave the opposite end of the antenna feed line is terminated with a properly adjusted resistor. This leads to the absence of standing waves in any of the legs of the antenna. This absorption ensures that the current maintains a progressive phase along the antenna, supporting unidirectional wave travel and stable radiation patterns. By matching the resistor value to the antenna’s characteristic impedance, reflections are minimized, resulting in consistent traveling wave behavior and improved directionality and bandwidth. The value of load resistance is generally around 600 to 800 ohms which is also the impedance. The Voice of America antenna system at the Bethany, OH Relay Station used re-entrant Rhombics, which were 90% efficient, by re-phasing the power, instead of heating up termination resistors. My antennas also uses the re-entrant system, the Rhombic is terminated in a transmission line, which in turn is coupled back to the input through the proper voltage-matching, and phasing networks. The antenna input impedance and radiation pattern are constant over a 2:1 or more range of frequencies. Their impedance is constant over a frequency range 4:1 or more, with the forward gain increasing at 6 dB per octave. The resultant pattern is the cumulative effect of the radiation at all four legs of the antenna. This pattern is directional, it can be made bi-directional by removing the terminating resistance. The maximum gain from a Rhombic is along the direction of the main axis, which passes through the feed point to terminate in free space. The polarization obtained from a horizontal Rhombic is in the plane of rhombus, which is horizontal. But portions of the radiation, which do not combine with the main lobe, result in considerable side lobes having both horizontal and vertical polarization, which can be very advantageous for ham radio use. The old books say, "The gain of a rhombic with side lengths of four to five wavelengths is over 40 times that of a half wave dipole. About one half of this gain is realized by using two wave lengths to each of the four sides" From the old DoD Book,.https://www.mapability.com/ei8ic/rhombic/text.php#:~:text=The%20gain%20of%20a%20rhombic,1 Maximum Size In modeling it seems to show that the maximum useable size of a rhombic is about 5 or 6 wavelengths per side. Much larger than this and the main lobe will split into a "V" pattern and you gain little else. A practical gain of around 16-18 dBd seems to be the peak of gain. The gain of a rhombic with side lengths of four to five wavelengths is over 40 times that of a half wave dipole. It is only after you actually measure the RF radiation pattern of what you simulate that you will gain a comprehensive understanding of what the antenna is truly doing at your specific location. This process involves several critical steps that are essential for accurate assessment and analysis. High-Frequency Stock Trading groups should be installing the rhombic antenna for their point to point use! Rhombics like K0UO's are big (long and take acres), but have very high forward gain with a large band-width. An Actual photo View of some of the ham equipiment Brig General Walz has three super station setups, at his KS location, using the most modern equipment, as well as top of the line vintage antigue restoredK0UO has years of expertise in contesting, DXing, using cutting-edge engineering and technology. K0OU uses many very high-gain directional LPDA-Yagis beamed at all continents, large 160 -40 meters four square verticals, stacked systems of rhombics, V-beams, and curtain arrays, The achieved goal has been met to have a world class station with multiple antennas combined (stacked) for increased gain and better performance on all the amateur bands, that are optimized for maximum gain. All utilizing optimum take off angles. One of K0UO'S Stations It can be truthfully be said, that "A Rhombic antenna occupies more space per db of gain than any other antenna". The Rhombic is a very high-gain antenna however, and it requires a lot of acres, and the efficiency when terminated is only about 50%. An alternate impedance-termination system, which I use, will take the efficiency to 90%, how ever it was only used for a few large shortwave broadcast stations, where input powers were above 50 kw, this system is called Re-entrant line termination making it highly efficient (90%). Drawing of K0UO re-entrant Rhombic that is now 90% efficient, by re-phasing the power instead of heating up termination units. In this system, the Rhombic is terminated using a transmission line system, which in turn is coupled back to the input through a proper voltage-matching, and phasing network system. Thus, the energy in the dissipation line is fed back to the antenna, so that considerably less than 50 percent of the energy is wasted. The old VOA Bethany site in Ohio had efficiency up to over 90%. This feeds-backs the wasted RF energy "In-Phase", back into the feeder end of the antenna. For any variation from the stubs frequency, the stub must be returned. I am now the only station (ham or Commercial) using, re-entrant line termination equipment, which is re-phasing the power, instead of heating up termination resistors. With a Re-entrant system, now the Rhombic has radiation efficiency to 90% Clyde Haehnlen SK, developed the specifications for the Voice of America antenna system at the Bethany, OH Relay Station. That re-entrant Rhombic is 90% efficient, by re-phasing the power instead of heating up termination units. In this system, the Rhombic is terminated using a transmission line system, which in turn is coupled back to the input through a proper voltage-matching, and phasing network system. Thus, the energy in the dissipation line is fed back to the antenna, so that considerably less than 50 percent of the energy is wasted. The old VOA Bethany site in Ohio had efficiency up to over 90%. This feeds-backs the wasted RF energy "In-Phase", back into the feeder end of the antenna. For any variation from the stubs frequency, the stub must be returned. K0UO is now the only station (ham or Commercial) using, re-entrant line termination equipment, which is re-phasing the power, instead of heating up termination resistors. Re-entrant line termination Clyde Haehnlen kindly provided me with the design information for re-phasing a few years before his passing .https://www.k0uo.com/post/termination-resistors desige of the re-entrant line termination patent drawing U.S. patent drawing. The Re-entrant Rhombic antenna is use at K0UO. The K0UO station uses Re-entrant Rhombic arrays making them the highest forward gain HF antennas with its 90% efficiency, The K0UO Rhombic Farm is using the array on many ham bands 160 meters to 6 meters, which involved considerable engineering time to get it right, this was not need by the VOA in the 1940s, they only used a few frequencies. To put it in perspective, my four arrays each cover an area equal to over five football fields (You need acres). These are the world's largest ham radio wire antenna arrays in use. The re-entrant K0UO Rhombic Arrays have much more gain than the massive stacked HF yagi beam arrays, that I had up previously. "A Rhombic antenna occupies more space per db of gain than any other antenna". So Don't underestimate the performance of the Rhombic, unless you have personally built and used one. Because of their excessive size (area) covering many acres, you see their real advantage of using thousands of feet of wire in the air, which creates receive and TX signal diversity, by capturing signals at different times and different angles, vastly eliminating fading QSB, and firing out the transmitted RF in the same way. Traveling wave antennas are very unique and unlike many other antenna in common use, and modeling will not show this major advantage. The KØUO Rhombic Antenna Farm in Kansas, consisting of many acres, with "Miles of Wire in the Air & On the Air". Best known as an antenna Experimenter, Ragchewer 1st and DXer for fun! "It takes years of Passion, Hard work, and Commitment to build a great station". I model all my antennas using NEC5 and HFTA (High Frequency Terrain Analysis) to evaluate the take of angle of the various antennas over real ground, then I do far field testing. The antennas physical variables are: (1) the required take-off angle to suit propagation and required signal path length (2) the length of the rhombic sides, usually about three to six wavelengths at the design frequency (3) the included angles of the rhombic (4) the height of the wires above ground, from one and two wavelengths. view from the top of one of the 100 antenna poles looking out at the 1200 acres antenna test range, larger than W8JI, K3LR stations by 100s of acres View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo,miles of antennas for ham radio and dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood powerline poles, concrete silos, and portable mobile towers also used for university research STEM programs, k0uo has the largest HF antennas in use from 160 meters to 6 meters, the Rhombic Array, used by amateur radio hams, DOD, commercial, broadcasters, K0UO are the world largest located on a 1200 acre antenna test range in kansas using an extensive array of over 20 towers and antenna supports K0UO Rhombic antenna farm which is the highest forward gain array and largest area on 1200 acres in use by any amateur ham station DX, remote, or contest station in current use any where in the world An actual photo view from the top of one of the many 100 foot Poles in use at K0UO My four antennas, each cover an area equal to five football fields. The Rhombic has one of the poorest gain-per-acre rankings of any high gain HF antenna array, however if you have the land, they can be a excellent high gain low cost solution. I now use a Re-entrant which is 90% efficient by re-phasing the power back in the antenna, instead of heating up termination resistors A Rhombic occupies a lot of space, volume and area When something "occupies volume, not area," it means it fills a three-dimensional space rather than just covering a two-dimensional surface. Volume refers to the amount of space inside a 3D object (measured in cubic units), while area refers to the amount of space covered by a 2D shape (measured in square units). For example, a box occupies volume because it has length, width, and height, while a sheet of paper only occupies area because it has length and width but negligible thickness. An antenna's physical volume influences its signal coverage range, primarily through its relationship with antenna size, shape, and how these factors interact with the operating frequency, and the areas surroundings. The key points are: Antenna Size and Frequency: The physical size of an antenna is typically matched to the wavelength of the signal it is designed to transmit or receive. Larger antennas (greater volume) can support longer wavelengths and may have higher gain or better efficiency at lower frequencies. The height the other part of the 3D volume: Determines takeoff angle, and also can affects the interactions with the ground (soil) under and near the antenna (ground losses), which be considered. Many big rhombic farms were build over saltwater marshes, for a reason. Aperture and Gain: Increasing the physical size (aperture) of an antenna can increase its gain, which focuses the signal more narrowly and extends the coverage range in specific directions. my antennas have 14 to +18 dBd of gain. All long Traveling wave antennas are known for fantastic Improvements in the reduction of QSB fading, for both transmit or receive. It is like Diversity, large arrays cover a lot of area. My station uses miles of wire, listening to signals coming in at different angles. Signal-to-noise ratio (S+N/N ratio, or SNR) is one technical aspect not too many amateurs give a second thought about, however if you can't hear them you can't work them. This is very apparent on audio reception, long Traveling wave antennas eliminates much of the audio amplitude fading for both transmit or receive. The RF signal is almost never in a stable phase relationship at both places at the same time. This means the signal will have random phase and amplitude differences. The arrival angle and polarization of incoming signals will change. This generally results in the fading, by having many wavelengths of wire in the air, the chances are that while one are on the wire experiences a fade, the other will not. The power is in the diversity, by the size of the array, and what you can with out QSB fading. Traveling wave antennas are just quieter and have substantial noise reduction. That is why so many people use the Beverage receive antennas. an Actual photo view from the top of a 100 foot pole, k0uo the largest HF antennas in use from 160 meters to 6 meters, the Rhombic Array, used by amateur radio hams, DOD, commercial, broadcasters, K0UO are the world largest located on a 1200 acre antenna test range in kansas using an extensive array of over 20 towers and antenna supports, The "KING of Wire Antennas" is a K0UO type Rhombic. and a View of the K0UO super station 3/8 galvanized 3/8" wire rope used for the big high gain Rhombic array wire cable miles for wire in the air at the K0UO super big gun contest and DX station View from the top of one of the 100 foot towers, 1500 feet from the Station Also a Rhombic antenna does have the distinct advantage of working over very wide frequency ranges, with flat SWR, and high gain. Something a basic mono-band yagi can never do. The Rhombic is also a very simple antenna, requiring only four supports, three supports for the V-beam, and one support for inverted V -beam derivatives. If you have a large rural property, you may want to design, build, and use a Rhombic Antenna. Varying the height of an antenna modifies the radiation patterns in both the vertical and horizontal planes, and also affect the over-all gain, particularly if the Rhombic has short length sides (2 wave lengths per side, or less). View of a S meter at K0UO station, To put it in perspective, my four arrays each cover an area equal to five football fields (You need acres). These are the world's largest ham radio wire antenna arrays in use. The re-entrant K0UO Rhombic Arrays have much more gain than the massive stacked HF yagi beam arrays, that I had up previously. The KØUO Rhombic Antenna Farm in Kansas, consisting of many acres, with "Miles of Wire in the Air & On the Air". Best known as an antenna Experimenter, Ragchewer 1st and DXer for fun! "It takes years of Passion, Hard work, and Commitment to build a great station. Antennas Before Amps The U.S. Army tech manual says: "Sometimes the antenna sides are deliberately made shorter to increase the vertical wave angle of propagation at higher operating frequencies, and to broaden the radiation pattern. The latter is usually necessary to offset ionospheric effects, which may cause a shifting of the communications path in long-distance communication. Regardless of the reasons for a compromise in the design, for optimum performance in a given frequency range, two basic factors must be considered. First, if the desired height cannot be attained, the length of the sides must be increased. Second, if the side lengths are shortened, the height of the antenna must be increased. In either case, the over-all efficiency of the rhombic is lowered. The term efficiency here refers to the signal gain and directivity for transmission in the forward direction, and signal-to-noise ratio for reception in the same direction." An Actual photo of K0UO control system boxes for the rhombic arrays 1200 feet from the main station A view of one of the K0UO control system boxes The Rhombic is excellent for point-to-point communications and exhibits a very low takeoff angle--a definite plus for DX, it also so has some higher angle which is great for ham use, it fills in the gaps. Very broadband Easy to construct Low cost High gain Low noise L should be long enough, 2 to 4L at the lowest frequency The values of q and a determining the shape of the main lobe Symmetry of the total antenna system, including balun, feed lines and resistor. This seems simple to do, but really is not! First you need a very good 12:1 current balun that works properly over the entire frequency range of the rhombic. You need a high power, non inductive load that is electrically symmetrical around a central ground tab (see info else where on this blog about where resistors can be found) Highly efficiency (90%) using, re-entrant line termination system The K0UO Rhombic Arrays have much more gain than the massive stacked HF yagi beam arrays, that I had up previously. Then you have a high gain antenna, with pinpoint accuracy. More Advantages The structure of the antenna is quite simple and it is cost affordable. It provides high directivity by radiating most of the power along the main axis. It provides efficient long-distance radio communication when installed in a large space. The offered input impedance is quite large. The radiation pattern and input impedance remain constant for a large range of frequency. These can be easily switched from one working frequency to another during operation. It suits long-distance F-layer propagation due to low vertical radiation angle. A excellent choice HF antenna for commercial, maritime shore stations, military, broadcasting, frequency agile, requirements, high speed traders, diplomatic, EME and ham amateur radio. Above: How to change the antenna directions by180 degrees Above: How to change the antenna directions by180 degrees A Rhombic reduces E-field gradient at the high the voltage points of the antenna. It solves the problem where antenna tips or ends were charged by a transmitter with very high voltages. A similar effect occurs when receiving when the environment around the antenna is charged from inclement weather. The very high voltage gradient between the antenna and the air around the antenna causes corona discharge. Which appears as a hissing, whining, sizzling, or popping noise in the receiver. The most intense charge buildup occurs at the highest point, farthest from earth and at a point away from other objects in open space. The shape of a Rhombic minimizes protrusions, and places a blunt edge towards the highest charge gradient areas alone the antenna. An yagi or dipole element, on the other hand, has protruding points that extend well out into clear air where charge density and voltage gradient is highest. During periods of inclement weather when precipitation static is highest, the horizontally polarized quad style element will not only have minimal exposure to high field gradients, the high impedance corona noise will not be as well matched to the receiving system. Less QRN and the RF energy will be transferred into the receive system. view of a ladder line surge protector used at the K0UO antenna farm DXE Ladder Line Surge Protector, helps with static. Works with 450 ohm or 300 ohm Ladder Line and 600 ohm open-wire feeder • Internal Gas Discharge Tubes, Capacitors and Resistors • Can withstand multiple surges and shunts them to ground • Bleeds off static charge collected from wind driven snow, rain and dust An Actual photo View of one of the many Relay control boxes on the 1200 acre K0UO antenna and test site Some of the Rhombic Control boxes, at K0UO An Actual photo view of the K0UO site looking to the SW from the Rohn 55 tower and a control boxes Just one of the K0UO Control Boxes, at the base of a Rohn 55 tower, with a view of some of the 100 foot poles on site An Actual photo View of one of the many Relay control boxes on a 100 foot antenna pole at the 1200 acre K0UO antenna and test site, ABOVE: One of the remote relay control boxes used at K0UO, or 1200 feet from the main Station OK now you can sketch out a 4λ-per-side rhombic antenna design tailored for 100-foot towers. This is a serious DX beast, a DXer and Contesters dream. 📐 Design Parameters (Assuming 40m Band) Wavelength (λ) at 7 MHz ≈ 42.8 meters (140.4 feet) Side Length: 4λ = ~171.2 meters (561.6 feet) Height: 100 feet (~30.5 meters) — excellent for low-angle radiation Acute Angle: ~47° is optimal for directivity and gain Termination: Use a 600–800Ω non-inductive resistor or go re-entrant for high efficiency 🧱 Layout Dimensions Component Measurement Side Length ~561.6 feet (4λ) Overall Length ~738 feet (tip to tip) Overall Width ~688 feet (widest point) Area Required ~5–6 acres Feed Point Height 100 feet (top of tower) Termination Height 100 feet (opposite tower) 🛠️ Construction Tips Support: Use four 100-foot wooden or metal towers at the rhombus corners. Wire: Heavy-duty stranded copper clad or aluminum, 3/8" preferred for durability. Feed: Balanced line or coax with a 12:1 balun at the feed point. Termination: Mount resistor between wire ends at the far acute angle, elevated to match wire height. 📡 Performance Highlights Gain: Up to 15 dB with proper termination and elevation Beamwidth: ~20–30° — razor-sharp directivity Elevation Angle: ~10–15° — ideal for long-haul DX Bandwidth: Covers multiple HF bands with acceptable SWR 🧠 Pro Tips for Optimization Re-entrant Termination: Even more power to the antenna, Reflect unused energy back into the antenna for ~90% efficiency — no heat wasted in resistors. Phasing Arrays: Combine multiple rhombics for steerable beams (MUSA-style). Ground System: Use radial or counterpoise network to minimize earth losses. 🖼️ Real-World Inspiration Is my K0UO Rhombic Farm in Kiowa, KS uses this exact configuration — 4 to 6λ legs on 100-foot poles, covering multiple DX paths with re-entrant terminations. It’s a living museum of wire antenna excellence. Antenna supports covering many acres at K0UO super station and antenna RF test range ham radio site, largest in the world. View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood power-line poles, concrete silos, and portable mobile towers An actual photo of a number of the 100 foot poles covering many acres at K0UO View of a very large roll of cable used by the miles by K0UO for the worlds highest gain arrays Miles of Wire Rope used at the Antenna Farm, Cable with Zinc coating helps: on higher HF bands (smaller skin depth), current stays mostly in the zinc layer; on lower bands, some penetrates steel but size still wins. Bottom line on efficiency: The 3/8" galvanized wire rope will generally have slightly higher efficiency (lower ohmic losses) than 12 gauge copper due to its enormous surface area overwhelming the material disadvantage. Both will exceed 95–99% efficiency in typical HF dipoles/inverted-Vs/loops (losses negligible compared to ground losses, matching, etc.). The difference is small—likely <0.5 dB—and favors the thicker rope, especially on lower bands (e.g., 80m/40m). The antennas wire cable have over 1000lbs of tension https://www.k0uo.com/post/using-wire-rope-cable-for-antennas-wire An Actual photo View of a very large roll 5000 feet of cable used by the miles by K0UO for the high gain arrays Miles of 3/8" triple galvanized wire rope is used for the antennas, the roll is 5000 foot, almost enough for one of K0UO's antenna! a model view of a rhombic Rhombic RF lobes Above: Note for amateur radio use, the minor higher lobes are very useful for making closer in contacts, I see this especially useful on 20 and 40 meters in the day time. The higher and split forward lobes were considered useless and a waste of RF power for the Point to Point stations in the past. I use it as an advantage to make more QSOs', just like fishing, the more hooks you put out, the more you catch! The ARRL did put the lobes to good use with their rhombic antenna for complete stateside coverage (1930 to 1980s). See the ARRL coverage chart below, and since going to other antennas, they have never been able to have the same consistent RF field strength throughout the lower 48 States. Drawing of the ARRL antenna from the 1930s FROM A OLD QST For day-to-day use of the antenna in amateur radio service, remember amateurs are not point-to-point shortwave broadcasters, military or wire-services. Amateurs just want to make QSOs! Also most amateur radio operators don't have tens of thousands of dollars to spend on tall towers and stacked mono-band beams, or the ability to climb and maintain such structures. Rhombic antennas were the ultimate antenna design back in the Golden Age of Wireless. However, building one required a large tract of land and a lot of tall power poles, because they have dimensions several times the wavelength. To most amateurs the positive thing is there are no large mono-band antennas to maintain, or rotators to fix, and rhombics allows for instantaneous direction and band switching. They normally can be installed at very low cost, if you have trees to hang them from, all that is needed is a lot of wire and time! I have four 40 meter resonant designed Rhombic traveling wave antennas in use, most use +2500 foot of cable each, for the antenna. The key concept with traveling-wave antennas is that there are no standing waves, which means that the current and voltage levels are the same everywhere along the antenna conductors. So the Rhombic antenna does have the very distinct advantage of working over very wide frequency ranges with flat SWR and high gain. a drawing of the biggest Rhombic arrays in the world at k0uo site A V Beam (Vee) is just 1/2 of a Rhombic Above is a control box used at K0UO, with a 12 to 1 current balun with lightning protection, this box was used at the W7YRV Rhombic site of Roy Callison's a drawing of stacking two rhombic arrays for higher gain Phase two or more arrays for more gain and better F to B View of miles of HF antennas from a 100 foot pole antenna support at k0uo site The Buzzards love to use the 100 foot poles for roost! View of some of the miles of antenna cable on a 100 foot wood pole with red marker cones for aircraft The red cones are for the my 4KS airport and FAA requirements View of some of the miles of antenna cable on a 100 foot tower and pole with red marker cones per the FAA for aircraft safety that use the 4KS Walz airport ABOVE: I USE A REINFORCED WITH ANGLE IRON, ROHN TOWER WHICH IS HINGED UP BY A CABLE ON THE POLE, THE TOWER IS MUCH EASIER AND SAFER TO CLIMB. SOME OF THE POLES ARE 36 IN DIAMETER AT THE BASE, SO YOU WOULD NEED A 10 LONG LANYARD TO GO AROUND IT! View of some of the miles of antenna cable at the top of a 100 foot tower and pole at K0UO AT 100 FEET View of some of the miles of antenna cable on one of the over forty 100 foot tower and pole at K0UO ABOVE: THE K0UO ANTENNAS USE 3/8 TRIPLE GALVANIZED WIRE ROPE CABLE AS THE ANTENNA RADIATOR WIRE. ALL THE CABLES GO THROUGH PULLEYS WHICH ARE STRETCHED TIGHT UP WITH CABLE PULLS ON THE GROUND FROM BOTH END OF THE DIAMOND SHAPED ANTENNAS ( @1000 TO 1500LBS OF PULL) View of hole drilled for the 100 foot poles at K0UO Jon Walz KDØDCO, K0UO's son, is on the skid loader drilling the 42"diameter by 10 foot deep holes view of setting one of the dozens of 100 foot wood power-line poles used at K0UO the largest ham radio station and antenna farm of 1200 acres in near Kiowa KS Setting a 100 foot pole with a 85 ft reach SkyTrek Telehandler loader View of the K0UO super station 3/8 galvanized 3/8" wire rope used for the big high gain Rhombic array wire cable miles for wire in the air at the K0UO super big gun contest and DX station 3/8" Triple Galvanized Cable is used for the antenna wire, with over a 1000lbs of tension on the cable for the longs spans between poles View of a larger skid-loader and a 100 foot fold-over tower at k0uo antenna site ABOVE: THE 100 FOOT TOWER IS REINFORCED WITH ANGLE IRON, AND THE LIFT CABLE IS AT 40 FOOT ON EACH POLE. THE TOWER FOLD OVER HINGE IS PERMANENTLY MOUNTED TO A SKID LOADER BUCKET, AND THE SKID LOADER IS JUST BACKED TO EACH ONE OF THE POLES THAT MIGHT NEED ANTENNA REPAIRS. AFTER THE TOWER IS RAISED THEN IT IS STRAPPED TO THE POLE EVERY 20 FEET. THE TOWER ALSO HAS A 3/8 SAFETY CABLE GRAB SYSTEM ON IT. 100% FALL PROTECTION IF YOUR NOT CONNECTED YOUR NOT PROTECTED. view of a 100 foot fold over antenna tower at k0uo THE TOWER IS MUCH EASIER AND SAFER TO CLIMB. View of the shop at k0uo building towers Building the Climb Tower Climb Tower in place Climb Tower in place View of one of the many 100 foot towers at the 1200 acre K0UO antenna and test site CLIMBING THE TOWER BY THE 100 FT POLES AT K0UO, it beats climbing the poles! Many of the Rhombic insulators are from W6AM's station (which were found at the TRW Southern California parking lot sale years ago). OVERVIEW of all the K0UO pages: The Rhombic antenna is a wide-band progressive traveling-wave (fast-wave) antenna, V-beams, Receive Directivity Factor (RDF) towers, VOA, W1AW, W6AM, Beverage traveling wave antenna, HF curtain, Broadcast tower, ham radio, balun for matching, IEEE, terminating resistor, E and H field, far field modeling, antenna measurements, NEC2 NEC4, k0uo, wire antennas, Curtain antennas, baluns, VOA sites, LPDA, W6AM, W7URA, Feed-lines, and 4KS Walz public Airport at Kiowa, KS. Welcome to K0UO.com, where we dive into the world of rhombic, curtain, and Vee Beam antennas at the 4KS Public Airport near Kiowa, KS. Explore the intricate world of rhombic antennas, Receive Directivity Factor (RDF) towers, Beverage traveling wave antennas, and so much more. Join us as we delve into the fascinating realm of antenna farming and ham radio technology, if your group has a school or University antenna or aerospace research STEM program, let me know. The KØUO Rhombic Antenna Farm and Test Range: Home to the World's Largest amateur radio (ham), High Frequency (HF) Wire Antennas. For Design see https://www.k0uo.com/post/rhombic-math-design K0UO G Mail Blog https://www.blogger.com/profile/08142301711468531870 SEE K0UO's CURTAIN PAGE, even more gain than a rhombic https://www.k0uo.com/post/current-distributed-feed-system-as-used-on-sterba-curtains-will-be-utilized-on-the-new-antenna K0UO has years of expertise in contesting, DXing, using cutting-edge technology, and engineering. The site also uses many very high-gain directional stacked and phased LPDA-Yagis beamed at all continents, large 160 -40 meters four square verticals, stacked systems of rhombics, V-beams, and curtain arrays, at this world class station for increased gain and better performance on all the amateur bands. Photo of the ARRL 5Band WAS award to K0UO with 5 more band endorsements added, to show that K0UO Steve Walz is a DXer and contester. WAS (10 Bands) 160M - 6M, No WAS on 60M, but have 50 states on 60 meters all without FT8 WAZ SSB, CW WAC 7 bands VUCC 6M 160-6 meters WAS, no FT8, 11 band, note 60 meters added, no ARRL 60 meters WAS! SEE Patents for Rhombic: US2517238A - Radiating termination for a rhombic antenna - Google Patents A good read, Big and Old 27dB antenna, https://wtfda.org/wp-content/uploads/mem/rhombic.pdf Traveling Wave Antennas Simplified https://www.youtube.com/watch?v=nPMk4pFBsWc 2 meter rhombic: @ https://www.youtube.com/watch?v=5XNaXZ2qz4Y SEE: Edmund Laport's "Radio Antenna Engineering", published by Mcgraw-Hill in 1952 Navy design book on rhombics. This may very well be a Navy'ized version of the War Department document (TM11-2611) 16 Rhombics https://www.youtube.com/watch?v=-z5O1LHEFlc The 1945 Army rhombic book A. E. Harper, "Rhombic Antenna Design", CY 1941 General Steve Walz V31KW/K0UO TO SEE the complete Blog list check @ https://www.k0uo.com/k0uo Steve's Group https://en.wikipedia.org/wiki/RSI_Corporation https://en.wikipedia.org/wiki/RSI_Corporation
At the K0UO rhombic farm and antenna test range, the world’s largest facility dedicated to advanced antenna design and testing, engineers push the boundaries of what’s possible. We don’t just guess antenna gain - we measure it meticulously, ensuring every antenna performs at its peak. The K0UO Antenna Test Facility ATF far-field range site and 4KS Walz airport offer a real-world learning environment in Kansas for STEM antenna projects. If your school or university has a research STEM program for antennas or aerospace, contact me. Building and experimenting can aid learning and development. The antenna range is a controlled testing environment used to measure and evaluate the performance of antennas. Known as "The K0UO & RSI Corp Antenna University" in the Fraunhofer zone (Far Field), and is an accredited wireless outdoor testing range laboratory Efficiency, Flexibility, Reliability Measuring the simulated RF radiation pattern of the antenna is essential to understand its performance at your location, involving crucial steps for precise assessment and analysis. View a a RF Survey testing class Steve Walz's company RSI Corp a Professional, Scientific, and Technical Services company of Kiowa, KS in 2002 formed an educational alliancae RSI Corp. - Radiofrequency Safety International wth NWOSU, RSI had offices and classrooms on the NWOSU Alva, OK campus, where they taught both University accredited, and Adult specialized courses. Many RF, RFI, EME, Telecom safety and other survey classes, using very specialized and very high end expensive RF equipment. The K0UO Antenna test range site in Kiowa KS is a reflection-free environment, and primarily used by Ham radio, STEM, commercial and military organizations for research and certification. this site is in conjunction with RSI Corp Kiowa, KS https://www.rsicorp.com/hazard-assessments, also teach how AI can be used, Radiofrequency Safety International RSI Corp and Steve Walz is using AI which is now becoming an advanced tool in analyzing, developing, and expanding research. This is the worlds largest ham station and antenna farm RSI Corp in Barber Country KS works with Hyperscale AI Data and Network operation Centers developing Environmental Health and Safety EH&S surveys and programs. RF Survey Class by Steve Walz and RSI Corp NWOSU team, "Antenna University" (Near & Far Field Testing) The scientific method serves as the foundation for all RFR antenna pattern testing activities at the K0UO test range. All surveys and tests must first be subjected to the rigorous processes of the scientific method. Modern programs using NEC2/NEC4 model RF absorption in the ground (Electrical Conductivity) under antennas with the Sommerfeld-Norton ground model. Older models inadequately address loss and ground reflections at low angles. Skywave signals form through antenna-ground interactions within 1 to 5 wavelengths in the Fraunhofer zone (Far Field). Ground losses affect some antennas more than others, and surrounding objects like buildings, trees, and fences in the near field also significantly impact performance, which models may not accurately depict. Real-world patterns might not align with theoretical models, unless you've tested the ground's electrical conductivity and the model incorporates that data. You can’t talk about antenna gain measurement without giving a shout-out to the K0UO rhombic farm and antenna test range. This place is legendary in the ham radio and commercial HF world. It’s the largest facility dedicated to advanced antenna design and testing. All antennas are modeled using NEC5 and HFTA (High Frequency Terrain Analysis) to evaluate the take of angle of the various antennas over real ground. an actual photo View of many of the 100 foot poles, at the k0uo the largest HF antennas in use from 160 meters to 6 meters, the Rhombic Array, used by amateur radio hams, DOD, commercial, broadcasters, K0UO has the world largest located on a 1200 acre antenna test range in kansas using an extensive array of over= 20 towers and =40 antenna supports at the K0UO & RSI Corp antenna test range and elevated lab in the far field of the large outdoor antenna range. View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood powerline poles, concrete silos, and portable mobile towers, specialized and very high end expensive equipment and large, reflection-free environments, is primarily used by Ham radio, STEM, commercial and military organizations for research and certification. this site is in conjunction with RSI Corp Kiowa, KS https://www.rsicorp.com/hazard-assessments Welcome to K0UO's premier ham radio antenna site farm, spanning hundreds of acres dedicated to innovative design and rigorous testing of antennas. The largest in the world, so join me in advancing the field of ham antennas radio with cutting-edge technology and expert guidance. This station has been very competitive, and has won many major worldwide amateur radio contest. High-Frequency Stock Trading groups should use the rhombic antenna. The Defense Technical Information Center is RSI's central facility for the collection and dissemination of scientific and technical training information. RSI supplies training and assessment services to the United States and other governments.Welcome to the K0UO Ham Radio Station, home the world's largest antenna site and test range, spanning impressive 1,200 acres. (since OH8X in Finland, tall tower and 160 meters beam in Finland. was destroyed by a storm in 2013).Featuring miles of antennas and towering structures—including FCC-registered reaching up to 195 feet—our facility is a dream destination for serious contester and big gun operators. With numerous -foot wooden powerline poles, concrete silos, and portable mobile towers, the K0UO Rhombic Farm stands out for its significant height and capabilities. Registered under Antenna Structure Registration number 1216715, our station is recognized in the FCC public file, credibility and verification that sets us apart from other so-called big gun ham stations. The station and antenna farm uses very complex highly engineered arrays. k0uo uses Re-entrant Rhombic array is one of the highest forward gain HF antennas with its 90% efficiency, the highest forward gain of any HF ham antenna. Also a world-class multiple stations, with many large LPDA yagi type beam antennas, 195 to 300 foot towers, and multiple very large wood power-poles. Antennas from 160 meters up to 2 meters. Using the new Icom IC7760 as the main transceivers. With 1200 acres near by to test and build all types of antennas and tower pole supports, also the largest ham radio station in the world with milrd of wire arrays and many towers, Antenna Test Facility ATF, electromagnetically-quiet area. Miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195, to 300 foot on a near by Gypsum hills site, numerous 100 foot wood power-line poles, concrete silos, and portable mobile towers. The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file. used in conjunction with RSI Corp of Kiowa KS seehttps://www.rsicorp.com/dtic. Use for DOD and commercial wireless telecommunications groups. RSI Corp can Handle technical management, RF testing logistics, and integration of measurement instrumentation in collaboration with the facility. The K0UO highly technical facility used to precisely measure an antenna's performance characteristics, such as its radiation pattern and gain. K0UO antenna test range site has significant out door real estate, so anechoic test chambers are not needed. https://www.rsicorp.com/dtic used as a Federal Communications Commission FCC, DOD, FAA and others test site this view is of the k0uo monster big gun super contest station and The Far Field Antenna Range consists of two signal towers, source and receive, situated 2500' apart. It features a heavy-duty, three-axis array positioner, capable of handling antennas up to 100 feet in diameter or larger, Near field and far field antenna field testing at the K0UO Rhombic antenna farm and range site, General Steven Walz's, known as K0UO 1200 acre antenna farm, The numbe one Amateur radio “Super Station” which is the worlds largest antenna site and test range with super ham station, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, at the 4KS Walz public Airport at Kiowa, KS and "Antenna University". https://maps.app.goo.gl/LQeAZCGkZxZ9D6Ky9 Down Range at the K0UO Antenna Test Range Rhombic Farm and elevated test stand, both Near field and Far field testing conducted at this site in Kansas Simulations provide a theoretical framework to approximate antenna performance using algorithms to predict behavior under conditions like frequency and polarization. However, they can't account for real-world variables such as nearby structures, terrain variations, and electromagnetic interference, which can affect performance. After simulations, conduct field measurements of the RF radiation pattern. This involves using equipment like an RF field strength meter or spectrum analyzer with calibrated antennas to capture emitted signals. By positioning the equipment at various locations and angles, you can gather data on the antenna's energy radiation in different directions, including gain and radiation pattern. The K0UO amateur antenna range, and testing site has the use of over 1200 acres around the main antennas and ranges, which are either owned, leased permission, or deeded right of ways (ROW), for far field measurements. It parallels the 4KS Walz airport making, it over 2500 feet for one of the far field ranges, using a portable tower and drones loaded with standardized calibrated RF, EME, and field strength survey instruments (used for DOD, Ham, and Commercial wireless telecommunication antennas). The K0UO is a highly technical facility used to precisely measure an antenna's performance characteristics, such as its radiation pattern and gain. K0UO has significant real estate or so anechoic chambers are not needed. both Near field and Far field testing is conducted at this site in Kansas The data from these measurements is invaluable, allowing visualization of the radiation pattern in polar plots or 3D visualizations. This reveals the main lobes where the antenna is most effective and any nulls or reduced signal areas, crucial for optimizing coverage and minimizing interference in wireless communication. Additionally, measuring the RF radiation pattern can identify discrepancies between simulated results and actual performance due to factors like physical installation, nearby objects, and environmental variations. Understanding these differences is essential for refining antenna design and improving system performance. Antenna gain is basically a measure of how well your antenna focuses energy in a particular direction compared to a standard reference antenna, usually an isotropic radiator (which radiates equally in all directions). Think of it like a flashlight beam - a narrow, focused beam shines farther and brighter than a wide, scattered glow. Understand that most HF amateur radio Yagi beam antennas and a large portion of commercial HF beams have not been tested on antenna test ranges today. Many VHF and higher band antennas have undergone some informal testing thanks to groups like The Central States VHF Society, Microwave Update, and others who annually set up amateur test ranges at their conferences. This is beneficial and highlights deficiencies in some manufacturers' models and claims. However, there is a complete absence of real-world far-field testing for HF antennas, such as wire-based and high-performance Yagi beams. Much of the manufacturer's documentation can be quite misleading to consumers. Why does this matter? Because in radio communication, focusing your signal means you can reach farther, cut through noise, and improve your overall signal quality. Whether you’re a ham radio operator trying to snag a rare DX contact or a broadcaster aiming for clear coverage, antenna gain is your secret weapon. But here’s the kicker - the gain you think your antenna has might not be the gain it actually delivers. That’s where antenna gain testing comes in. It’s the process of measuring your antenna’s real-world performance, so you know exactly what you’re working with. In summary, the act of measuring the RF radiation pattern is not merely a technical requirement; it is a vital process that informs you about the antenna's real-world effectiveness and efficiency at your location. It bridges the gap between theoretical predictions and practical applications, ultimately leading to better system design, enhanced performance, and more reliable communication networks. The primary purpose of an outdoor test range is to provide a dedicated and controlled area for the testing and evaluation of systems and technologies under realistic conditions. This is particularly crucial when laboratory simulations and indoor testing are insufficient to capture the complexities of real-world environments. RF near and far field testing following many protocol like IEEE-299, MIL-STD-285, NSA 65-6, CTIA CATL certification testing along with: Probe symmetry and amplitude ripple measurements. RSI can do Technical writing to USAF T.O., DOD, Army TM, NAVAIR standards, Motorola, IEC 1082, and other commercial standards. an actual View in photo of the 1200 acre antenna test range to test and build all types of antennas and tower pole supports, also the largest ham radio station in the world with miles of wire HF arrays and many towers, Antenna Test Facility ATF, electromagnetically-quiet area. View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood powerline poles, concrete silos, and portable mobile towers. The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file. used in conjunction with RSI Corp of Kiowa KS seehttps://www.rsicorp.com/dtic.specialized and very high end expensive equipment and large, reflection-free environments, is primarily used by Ham radio, STEM, commercial and military organizations for research and certification. this site is in conjunction with RSI Corp Kiowa, KS https://www.rsicorp.com/hazard-assessments, also Use for DOD and commercial wireless telcom groups groups, view shows some of the many pole and towers at the K0UO monster big gun super contest stations A few of the antenna support poles at my site The K0UO amateur ham radio and commercial antenna range Antenna Test Facility ATF, is in an electromagnetically-quiet area, and testing site has the use of over a 1200 acres around the main antennas for far field measurements, using a portable tower or drone loaded with calibrated RF, EME, power density, field strength, and non-ionizing radiation survey instruments, (also has been used for DOD and Commercial measurements). an actual photo view of one of the 100 foot wood pole on a road going into the antenna test range and kouo Rhombic farm, outlining, ownership is FCC License of k0uo written permisson required and the site has CCTV to enter the antenna testing range. Rhombic Farm KØUO: Home to the World's Largest amateur radio (ham), High Frequency (HF) Wire Antennas, the site is using AIView of the RSI Corp. - Radiofrequency Safety International RSI Corp and Steve Walz is using AI and new is now becoming an advanced tool in analyzing, developing, and expanding research. One of the many 100 foot Power-line Poles, this one is on a road leading into the K0UO Antenna Farm and Test Range site IAntenna range testing is crucial for ensuring the efficiency, reliability, and even regulatory compliance of antenna systems. By providing precise performance measurements and reducing interference, antenna ranges contribute to the development of high quality antennas for modern communication networks. As technology evolves, these testing facilities will continue to be instrumental in enhancing connectivity and innovation across various industries. In fact we are using AI, which is now becoming an advanced tool in analyzing, developing, and expanding research in RF and antenna. The following equipment is what my group, RSI will normally use to perform an RF test assessment: Signal generator for the test source Vector or scalar network analyzers Calibrated RF Meter Calibrated E-Field Probe Calibrated H-Field Probe Calibrated Personal Protection Monitor 2 Meter “Story Pole” Digital Camera Film Camera Sling Psychrometer GPS/GNSS and magnetic locator Tape measures or survey lasers and optical equipment, with range poles, Trimble S3 with robotic function and 5000 meter range Portable tower, and or drones with calibrated antennas and equipment Real time data acquisition computer system for automated pattern measurement A view of my company, RSI doing testing, in 2002 formed an educational alliance with NWOSU, RSI had offices and classrooms on the NWOSU Alva, OK campus, where they taught both University accredited, and Adult specialized courses. Many RF, RFI, EME, Telecom safety and other survey classes and have conducted over 30,000 surveys this photo is the RSI K0UO team testing The Re-entrant Rhombic array is one of the highest forward gain HF antennas with its 90% efficiency, now with very high gain, and low noise receive characteristics. Our Team in Action at a Telecom-site, Jon Walz "KD0DCO" of Concrete Walz & RSI Corp Some equipment may have a limited frequency range or be very directional. Most RF probes used at communication sites are field dependent. At sites with transmitters below 300 MHz for EME/MPE testing, both the magnetic and electric fields must be measured, as either could be dominant. Additionally, the site may be assessed for induced and contact current hazards. An RF assessment or NIER Report at any RF site is complex and requires a trained, competent, and qualified assessor with extensive site knowledge and proper equipment. an actual photo View of The K0UO Rhombic and antenna test range which has a FCC tower number 1216715 on site, with many other towers and antenna support poles. largest out door antenna and test range The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file How Signal Gain Measurement Works in Practice Now, you might be wondering, “Okay, but how do you actually measure antenna gain?” Great question! The process can be surprisingly straightforward or quite complex, depending on your setup and accuracy needs. Here’s the gist: Reference antenna setup: You start with a known antenna whose gain is already established. Test antenna placement: Place the antenna you want to test in the same position and orientation. Signal transmission: Transmit a known signal from a source antenna. Signal reception: Measure the received signal strength with both antennas. Calculate gain: Compare the received power levels to determine the gain difference. At K0UO,we use a massive open field with precise positioning systems and calibrated equipment to get ultra-accurate measurements. But for many of you, a smaller test range or even a controlled indoor environment can work if you’re careful. One tip I learned the hard way: make sure there’s minimal reflection and interference during testing. Nearby metal objects, buildings, or even the ground can mess with your readings. Using a turntable to rotate the antenna and plot the radiation pattern is also a game-changer. Air view from Google map of K0UO antenna site, see the three special-purpose target test beds make this facility unique. The wet sites on is 10 acres, two smaller ponds 1 to 3 acres, creates a simulated sea environment used to investigate background clutter and target-to-surface interactions. the site does HPM/Transient Electromagnetic, and RCS/radar signature at the test facility. specialized, large-scale antenna test range and research site located at the 4KS Walz public airport near Kiowa, KS see Google map at shttps://maps.app.goo.gl/LQeAZCGkZxZ9D6Ky9 The K0UO Rhombic Farm and the 4KS Walz Public airport and K0UO & RSI Corp antenna test range The K0UO RSI Corp RF test range site can provide test aircraft fitted with an electro-optical, infrared EO/ISR sensor, operator mission, tactical radios, and data link a testing area at the 4KS Walz airport. TEST SITE @ https://maps.app.goo.gl/LQeAZCGkZxZ9D6Ky9 My company RSI Corp back in 2002 formed an educational alliance with NWOSU, RSI had offices and classrooms on the NWOSU Alva, OK campus, where they taught both University accredited, and Adult specialized RF and agriculture courses. The NWOSU campus office was under the leadership of Gary Gerber "KB0HH", teaching courses like Superior Survey Techniques SST (RF) which follows a book of the same name, that I wrote in 1998. https://www.rsicorp.com/sst https://www.rsicorp.com/technicalcourses https://maps.app.goo.gl/Nm6zCyGzFTn2bfDN9 an actual photo of k0uo Steve Walz training class, in 2002 formed an educational alliancae RSI Corp. - Radiofrequency Safety International wth NWOSU, RSI had offices and classrooms on the NWOSU Alva, OK campus, where they taught both University accredited, and Adult specialized courses. Many RF, RFI, EME, Telecom safety and other survey classes, using very specialized and very high end expensive RF equipment and the K0UO large, reflection-free environments, is primarily used by Ham radio, STEM, commercial and military organizations for research and certification. this site is in conjunction with RSI Corp Kiowa, KS https://www.rsicorp.com/hazard-assessments, also teach how AI can be used, Radiofrequency Safety International RSI Corp and Steve Walz is using AI and new is now becoming an advanced tool in analyzing, developing, and expanding research. RSI clients include Verizon, AT&T, T-Mobile, the Department of Defense, Google, Black & Veatch, UPS, and FedEx. Steven Walz Teaching at NWOSU 2004 at the Radiofrequency Safety International's class room located in Vinson Hall RSI’S Radiofrequency Safety International Technical group has performed technical, safety, RF EME and general hazard inspection assessments at thousands of sites throughout the country, including many major broadcast sites, tower antenna farms, major buildings, and DOD installations. Radiofrequency Safety International and Steve Walz is using AI, which is now becoming an advanced tool in analyzing, developing, and expanding research. https://www.rsicorp.com/technical-inspections https://www.rsicorp.com/technicalcourses photo view of Steve Walz Teaching an RF Survey Class at NWOSU at Alva Ok 2004. RSI Corp in 2002 formed an educational alliance with NWOSU, RSI Corp. - Radiofrequency Safety International had offices and classrooms on the NWOSU Alva, Oklahoma campus, where they taught both University accredited, and Adult specialized RF and AG courses. Like Superior Survey Techniques SST (RF) which follows a book of the same name that Steve Walz wrote in 1998.specialized, large-scale antenna test range and research site located at the 4KS Walz public airport near Kiowa, KS An actual photo of a RF Survey Class Steve Walz and RSI with NWOSU, (Near Field Testing) Because EME/RFR is considered a physical hazard, proper programs must be in place to ensure safety at an RF test site. This is just like noise or air pollution. Everyone knows about and has noise and air sampling done; the same application applies to electromagnetic energy emissions. Testing must be done by a qualified EME/RF person. View of a RSI RSI Rooftop Visual Audit™ (RVA) will help you make sure you are being paid for what you have on your rooftop. Are there unlicensed transmitters you didn’t even know were there? Are there antennas still up on your roof from renters no longer paying you? https://www.rsicorp.com/rva RSI Corporation can help you enhance your building’s revenue stream and decrease your liability by being your partner in understanding your cooling towers and AI center better. RSI Corp in Barber Country KS works with Hyperscale AI Data and Network operation Centers developing Environmental Health and Safety EH&S surveys and programs. A RSI Corp RF Survey and Report RSI Corp: Rooftop Visual Audit Testing must be done by a qualified EME/RF professional Training must be done for workers who may be exposed to EME/RF above the uncontrolled levels so they can recognize and avoid the hazard A Plan must be in place The Rooftop Visual Audit™ will include: Map of Rooftop layout including antennas and associated equipment areas showing both licensed and unlicensed occupants Inventory of antennas including: Operator (if information is available at the site) Antenna type and MFG/Model as available Photographs of all antennas and associated equipment areas RSI Virtual University, exclusive online certification training program. See RSI Corp: Virtual University view of the cover of Mobile Radio Technology (MRT) magazine in March 1997 cover page, with the RSI Corp. - Radiofrequency Safety International and Steve Walz's RF Survey article Mobile Radio Technology (MRT) magazine in the late March 1997 cover page, with the RSI and Steve Walz's RF Survey article Above: Mobile Radio Technology (MRT) magazine March 1997 cover page, with the RSI and Steve Walz's performing an RF Survey, and a complete article on the procedures an actual photo view of a 100 foot and 195 foot towers in use at the world biggest ham radio staion K0UO Two of the taller steel towers in use at K0UO a 100 foot on the left and a 195 on the right with HF LPDA beams on top AI technologies are used to enhance the efficiency and accuracy of antenna design, quickly generate simulation results, and fine-tune antenna size and shape for improved performance and is an advanced tool in analyzing, developing, and expanding research in RF and antennas view of layout work for the qualified RF team at work setting up for EME RF RFR testing at the 1200 acre General Steven Walz K0UO test antenna range in view is K0UO FCC TOWER NUMBER AR #1216715 a 195 foote at the Antenna Test Facility ATF specialized, large-scale antenna test range and research site located at the 4KS Walz public airport near Kiowa, KS Layout out before testing The assessment must be repeatable. The methods and procedures must be able to stand the scrutiny of a FCC, DOD, zoning board or city councils, as well as the possible scrutiny of a legal representative. My team uses industry standard procedures for environmental assessments, which have been able to stand the test of time. This uncertainty term encompasses all non-repeatable errors stemming from the receiver, cables, temperature, variations in the AUT, and similar factors. It is anticipated that temperature fluctuations can be a factor at an outdoor range, and the source antenna might be affected by movement due to wind. Furthermore, scattering caused by the dynamic nature of the terrain and trees between the source and AUT is included in this term. The best method is to estimate this quantity is by comparing the far-fields from two or more azimuthal scans conducted with identical scan parameters. Ideally, K0UO uses five or more repeat measurements are taken without altering the measurement system. Then the far-field patterns of these repeat measurements are averaged, and this average is compared to a single measurement through complex plot subtraction. The pattern comparison and the RMS level are then utilized to determine the estimated uncertainty. drawing of a K0UO far field antenna test range, one test range is now over 3000 feet, along side of the 4KS Walz airport Outdoor Far field antenna test range setup Conclusion Antenna range testing is crucial for ensuring the efficiency, reliability, and regulatory compliance of antenna systems. By providing precise performance measurements and reducing interference, antenna ranges contribute to the development of high quality antennas for modern communication networks. As technology evolves, these testing facilities will continue to be instrumental in enhancing connectivity and innovation across various industries. Antenna Gain: How well an antenna amplifies a signal in a particular direction. Antenna Pattern: The 3D radiation pattern showing the directionality of the antenna. Input Impedance Frequency range Polarization Radiation Efficiency Radiation Pattern The Range Facilitates R&D and Innovation, Provides a dedicated environment for engineers, researchers and radio ham to develop and validate new antenna designs efficiently. The best equipment on the market today can have as much as 4 db of error. These items can in some cases be addressed and mitigated with proper training. Some of the other equipment could have as much as 30 db of error in complicated environments The Rhombic antenna farm, which was engineered and built single handed, stands as a testament to advanced engineering and design in the field of telecommunications. This facility is not just a simple installation; it encompasses a sophisticated array of technologies and infrastructure that enable effective communication over vast distances. Among its most notable features are the massive Rhombic antennas and beverage antennas, both of which are designed for optimal performance in receiving and transmitting signals. an actual photo View in photo of some of the K0UO Antenna Test Facility ATF 1200 acre antenna range, and test site with the worlds largest ham radio antennas, towers, poles Rhombic and V Beam antennas . View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood powerline poles, concrete silos, and portable mobile towers. K0UO antenna range is a controlled testing environment used to measure and evaluate the performance of antennas.k0uo the largest HF antennas in use from 160 meters to 6 meters, the Rhombic Array, used by amateur radio hams, DOD, commercial, broadcasters, K0UO are the world largest located on a 1200 acre antenna test range in kansas using an extensive array of over 20 towers and antenna supports Rhombic Farm KØUO: Home to the World's Largest amateur radio (ham), High Frequency (HF) Wire Antennas View from the top of a 195 foot tower showing the antennas, that cover many acres and the 4KS Walz public Airport at Kiowa, KS. Testing the Rhombic Arrays The Rhombic antennas, known for high gain and directivity, are positioned to optimize effectiveness across frequency ranges. Their geometric shape enables precise signal capture, ideal for long-distance communication. Beverage antennas, low-profile and used for receiving, excel with low-angle signals, enhancing distant transmission reception. All antennas have been tested in the far field to assess performance and reach. These measurements evaluate signal strength and quality at various distances, allowing for optimization. This ensures the station operates efficiently and meets modern communication demands. NOTE, Don't underestimate the performance of the Rhombic, unless you have personally built and used one. Despite their large size, Rhombic antennas use thousands of feet of wire to capture signals at different times and angles, reducing fading and enhancing transmission. Traveling wave antennas are unique, and modeling will not show this major advantage. Modern alternatives still can't beat the big HF Rhombic: Using K0UO +90% re-entrant re-phasing system no power is lost by terminating resistors. Yagis even stacked ones,( 4 over 4 over 4 at 200 feet have about the same gain) Log-periodic antennas Vertical phase arrays, 4 Sqs Wire antennas with tuners Phased dipoles The Best Antenna is one that is "In the Air and On the Air"! As any good antenna experimenter knows, the more antennas the better, that way you can test and see how they are really working. You won't know you have a good antenna if you can't compare it with others! The K0UO RSI Corp Antenna Test Facility ATF near Kiowa, KS, is in an electromagnetically-quiet area. Air view map of the part of the 1200 acres test site with all types of antennas and tower pole supports, also the largest ham radio station in the world with high gain arrays and many towers, Antenna Test Facility ATF, electromagnetically-quiet area. View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood power-line poles, concrete silos, and portable mobile test lab and towers. The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file. used in conjunction with RSI Corp of Kiowa KS seehttps://www.rsicorp.com/dtic. Use for DOD and commercial wireless telcom groups groups Air view of the Center of the K0UO Antenna site and the 4KS Public Airport TEST SITE https://maps.app.goo.gl/Nm6zCyGzFTn2bfDN9 The range is in a very rural area, near the center of the United States, the integrity of the test results have no RFI the from external interference. Massive scale: The range is known for its size and extensive collection of antennas, and towers, which is rare for an individual operator. Low interference: The remote, isolated location means the antennas are in an electromagnetically quiet environment, which is ideal for accurate and high-quality testing. Extensive equipment: The facility houses in the aircraft hanger, many different types of antennas and equipment, used for a variety of tests and research. Open and clear land: The rural setting, with its open spaces and clear fields, is visually striking to antenna enthusiasts. Photo shows a clear view of the 1200 acre ham radio and Electromagnetic Antenna Test Facility ATFt Facility RF antenna test range from a top of one of the 200 foot towers. The site uses specialized and very high end expensive RF EME equipment and large, reflection-free environments, is primarily used by Ham radio, STEM, commercial and military organizations for research and certification. the photo show the large outdoor area with a variety of terrain types for conducting user defined experiments this site is in conjunction with RSI Corp Kiowa, KS https://www.rsicorp.com/hazard-assessments An actual photo view to the west of the main K0UO station from a 200 foot tower, I can use all the land for over a mile around the antenna site. No other RFI in the area helps! Furthermore, the station is situated on an expansive property that consists of up to 1200 acres, which is either owned, leased permission, or deeded right of ways (ROW), around the antenna farm site. This substantial land area provides ample space for the installation of additional antennas, equipment, and support structures, as well as buffer zones that minimize interference from external sources. The strategic layout of the antennas across this vast expanse is carefully planned to reduce signal degradation and enhance overall performance. an actual photo View of K0UO on a tower doing RF testing, over 30,000 RF Telecom site surveyed by Walz's team at RSI corp. The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file 1200 acres to test and build all types of antennas and tower pole supports, also the largest ham radio station in the world with milrd of wire arrays and many towers, Antenna Test Facility ATF, electromagnetically-quiet area. View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood powerline poles, concrete silos, and portable mobile towers. The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file. used in conjunction with RSI Corp of Kiowa KS seehttps://www.rsicorp.com/dtic. Use for DOD and commercial wireless telcom groups groups RF Near Field Testing by one of the RSI Corp employees The combination of cutting-edge engineering, advanced antenna technology, and a large operational footprint positions the K0UO Antenna Farm and Test range site as a leader in the field, capable of meeting the evolving challenges of telecommunications in an increasingly connected world. This comprehensive setup not only serves current communication needs but also allows for future expansion and adaptation as technology continues to advance. RSI and myself has done RFI investigation work as an ARRL Voluntary Consulting Engineer (VEC), and Technical Specialist, and has provided technical assistance to many, by investigating RFI issues and finding the sources of the RFI. Photo view of Steven Walz K0UO RF Testing equipment on a very large drone, the RFR EME Test equipment is specialized and very high end expensive equipment and large, the site is areflection-free environment, and is primarily used by Ham radio, STEM, commercial and military organizations for research and certification. this site is in conjunction with RSI Corp. - Radiofrequency Safety International RSI Corp Kiowa, KS https://www.rsicorp.com/hazard-assessments. the large outdoor area with a variety of terrain types for conducting user defined experiments We can use large drones with RF meters for acceptance testing in the Far Field for detailed data on takeoff angles and gain measurements. To conduct the measurement using a drone at the K0UO test range site, the operator designs a flight path by determining the measurement width in azimuth and elevation, along with the granularity of the measurement lines. The drone autonomously follows this grid path, ensuring constant pointing and polarization alignment with the Antenna Under Test (AUT). The results are produced by combining the measured RF levels with the calculated angular position of the drone relative to the AUT. The data points are interpolated and displayed in a heat-map or 3D diagram. This process requires approximately 10 to15 minutes of flight time, with results generated instantly. These results then allow users to: Implement contours and calculate the 3 dB beamwidth along with the Front to Back (FB) ratio Compute beam center Verify levels against regulatory masks Compare results between models and measurements The Report a view of a RF report RSI's MPE Reports are a cost effective way to be sure! (NIER Report) see https://www.rsicorp.com/mpe-modeling, RSI Corp in Barber Country KS works with Hyperscale AI Data and Network operation Centers developing Environmental Health and Safety EH&S surveys and programs. Model and Field Testing Reports Metrology is the scientific study of measurement just the ability to measure alone is insufficient; standardization is crucial for measurements to be meaningful. An example of this was the testing of the Rhombic arrays 160 to 6 meters, for the design maximum gain, the azimuth of maximum gain, steering of both direction and azimuth, design side-lobes, and the back-to-front ratio. A calibrated, W&G EMR meter for both the E and H field is used, with the use of a portable tower or drone in the far field at precise predetermined positions. This allowed the for the most suitable method of conducting the test measurements. The analysis and its feedback mechanisms are a major part of K0UO's projects. All test at the K0UO range is done in the Far Fields, or the Fraunhofer zone which is the area where changes in distance from the antenna no longer produce a noticeable change in pattern shape or field impedance. All arrays have been modeled using EZNEC and HFTA (High Frequency Terrain Analysis) to evaluate the take of angle of the various antennas over real ground A drawing of an antenna testing layout, All test at K0UO is done in the Far Fields, or the Fraunhofer zone which is the area where changes in distance from the antenna no longer produce a noticeable change in pattern shape or field impedance.Used at the k0uo Antenna Test Facility ATF. the 2500 foot and 3500 ranges has a test antenna end of the range has a multiple axis hydraulic, heavy lift azimuth over elevation over azimuth test antenna positioner located next to the control room building shown in the figure. The terrain elevation profile of the range is also on file for use. Antenna Testing in the Far Field Also you need to understand Traveling Wave Antennas, like the Rhombic, some programs will not model them correctly. Explained The classification of rhombic and V Beams antennas as traveling wave antennas indicates that they operate based on the principle of wave propagation along the antenna structure. Unlike standing wave antennas, which have fixed points of maximum and minimum voltage (standing waves), traveling wave antennas like the rhombic utilize the continuous movement of waves along the length of the antenna. This results in a more uniform radiation pattern and often leads to enhanced performance in terms of signal strength and clarity. Capture area or Effective Aperture is determined by antenna gain and the wavelength, not by antenna physical size. All the Rhombic and V Beam antennas are field tested to confirm the design values, which concluded that the amplitudes & phases of the currents in the radiators conform with the antenna model. The antennas are readjustment as needed for max gain and best F/B. The radiation pattern of an HF antenna is formed as a result of reflection by the ground, and it may also be modified by currents flowing in the support structure. Data regarding the gain, accuracy of beam shape, and slew angle, as well as side lobe level and the amplitude of the radiation both in the minima and to the rear of the antenna, this was determined through real measurements. It is difficult to predict from the amplitudes and phases of the current flowing in the radiating elements. If significant discrepancies between design and actual performance are found, such measurements are advantageous as changes are made. K0UO proof tests fall into three categories: (1) Comprehensive evaluation of radiation patterns, impedance, and gain for the antenna on 40 & 20 meters. (160, 80, 30, 17, 15,12, 10 & 6 meters were considered secondary, but also tested) (2) The minimum practical tests provided proof of performance of the installed antenna on 40 meters @ night time "F layer", and Daytime with "D layer absorption". (3) Compares forward gain at the desired azimuth and elevation angle to average gain over the entire hemisphere E & H meters below are used for the field testing Photos of Electromagnetic Test Facility equipment at K0UO, antenna designers as a precision laboratory specializing in the testing of prototype antennas and RF devices. The K0UO & RSI Corp test and measurement facilities feature state-of-the-art equipment/software in RF performance, RF Survey test equipment used at the K0UO site Above: Wandel & Goltermann E&H Field power density meter with fiber optic cable to PC, the meter-probe is on the crank-up test tower and uses a fiber cable down to the PC for data collection. Also can use a E&H Field power density meter mounted on a large commercial drone. K0UO is using Ace HF Pro and IONSUM, which are computer programs using the output of the IONCAP prediction method to determine the most suitable frequency band and required antenna gain under specific averaged conditions. The acronym stands for IONCAP SUMmary. Propagation predictions form an essential tool in the management of a HF wanting to work DX Stations. The data from such predictions are used to specify the types and operating frequency ranges required to work the DX by allowing for changes in the antennas take off angle to achieve maximum signal to the desired direction. Which it is used to contact DX stations utilizing both long path or short path on F layer, or to contact North American stations on daytime with high D layer adsorption (160, 80, 60 & 40 meters). Some reflection can be obtained from the D region, but the strength of radio waves is reduced; this is the cause of the marked reduction in the range of radio transmissions in daytime on the HF lower bands. The K0UO station uses real time ionosonde (vertical HF RADAR ionospheric height-finder) data and ACE-HF Network, by Long Wave Inc which allows K0UO to analyze the entire HF spectrum using a single fixed transmitter location and multiple receive locations. The 64 Bit application has enhanced features and uses Google Earth and Google Maps to provide detailed HF Area Coverage Maps. And uses, and is part of real time GPS observables network to measure properties of the electron density such as the total electron content (TEC). The TEC is a measure of the total number of electrons that would be contained in a cylinder that extends up vertically above a given point on the earth all the way through the ionosphere K0UO uses, and was part of a real time GPS observable network to measure properties of the electron density such as the total electron content (TEC). The TEC is a measure of the total number of electrons that would be contained in a cylinder that extends up vertically above a given point on the earth all the way through the ionosphere. The ACE HF Pro, by Long Wave Inc allows the K0UO station to analyze the entire HF spectrum using a single fixed transmitter location and multiple receive locations. The station uses ionosonde (vertical HF RADAR ionospheric height-finder) data. Steve Walz uses software for antenna modeling 1200 acres to test and build all types of antennas and tower pole supports, also the largest ham radio station in the world with milrd of wire arrays and many towers, Antenna Test Facility ATF, electromagnetically-quiet area. View of General Steven Walz 1200 acre world largest antenna site and test range, k0uo ham radio station k0uo, miles of antennas for ham radio dozens of tall antenna support structures, like FCC registered towers up to 195 foot, numerous 100 foot wood powerline poles, concrete silos, and portable mobile towers. The K0UO Rhombic farm and antenna test range is one of the very few ham radio stations that has a tower which is tall enough and required by the FCC to have a registration. The Antenna Structure Registration or ASR tower number is 1216715. So the K0UO site, station, and antenna is in the FCC public file. used in conjunction with RSI Corp of Kiowa KS seehttps://www.rsicorp.com/dtic. Use for DOD and commercial wireless telcom groups groups Radio propagation analysis showing optimal communication frequencies across the Americas, with charts depicting signal-to-noise ratios and frequency reliability over a 24-hour period. The Fresnel Region: An In-Depth Exploration The Fresnel region, often referred to as the near field, is a critical area in the study of electromagnetic radiation, particularly in the context of antennas and wave propagation. This region is characterized by the fact that the radiation field pattern or shape is still in the process of formation, which means that the characteristics of the electromagnetic waves are not yet fully developed. The complexity of this region arises from the interaction of the emitted waves and the environment, leading to a variety of phenomena that can influence the overall performance of the radiating system. One important aspect of the Fresnel region is its relationship to induction field areas. Depending on the specific configuration and design of the radiating source, the Fresnel region may or may not encompass these induction fields. Induction fields are areas where the electric and magnetic fields interact in a manner that can induce currents in nearby conductive materials. The presence or absence of these induction fields can significantly affect the behavior of the radiation pattern and the effective range of the antenna. In the case of physically large arrays, such as the K0UO Rhombic site, the Fresnel zone will extend out several wavelengths from the source. This extension is due to the size and scale of the array, which creates a more complex interaction with the surrounding environment. The larger the array, the more pronounced the effects in the Fresnel region become, as the emitted waves can interfere with one another, creating constructive and destructive interference patterns. This can lead to a variety of radiation characteristics that are unique to the specific configuration of the array. Furthermore, the field impedance within the Fresnel zone is another crucial factor to consider. The field impedance, which is a measure of how much the electromagnetic field resists the flow of energy, may or may not have been established within this region. This means that the impedance can vary significantly depending on the distance from the source and the specific characteristics of the surrounding medium. As the electromagnetic waves propagate through the Fresnel zone, they may encounter different materials that can alter their impedance, leading to changes in the radiation pattern and efficiency of the antenna. In summary, the Fresnel region is an essential area of study in electromagnetic theory and antenna design. Its unique characteristics, influenced by the size of the radiating array and the presence of induction fields, play a pivotal role in shaping the radiation field pattern. Understanding the complexities of the Fresnel zone, including the establishment of field impedance, is crucial for optimizing antenna performance and ensuring effective communication in various applications. Some of the K0UO QTH is located in a wetland area on a creek bottom, characterized by high alkalinity and salt content. The nearby farmland, extending up to two miles away, has very high conductivity due to its red, iron-rich soil. The primary grounding is provided by a 5400-foot-deep oil well casing. Electrical Conductivity (EC) refers to a material's ability to conduct an electrical current, typically measured in milliSiemens per meter (mS/m). The presence of more ions, whether from acidity or basicity, enhances electrical conductivity, thus increasing the EC in soil. The Wenner "4-point or 4-pin Method" is the most common technique for assessing soil resistivity for broadcasters and communication sites. This method involves spacing probes 5 feet apart to measure resistivity at a 5-foot depth. Similarly, spacing the probes 40 feet apart yields a weighted average soil resistance from the surface down to 40 feet. This raw data is often processed with software to analyze soil resistivity as a function of depth. The accompanying photo shows three wooden pine poles supporting the radiating antenna cables surrounded by water; when the soil is drier, it has a very high salt content and is composed of red, iron-rich dirt. During winter months, up to six Beverage receive antennas, each ranging from 1000 to 1500 feet, are utilized in this area and the adjacent winter wheat fields. View of just some of the highly technical equipment and RF meters used at the K0UO facility, needed to precisely measure an antenna's performance characteristics, such as its radiation pattern and gain. K0uo has significant real estate or so anechoic chambers are not needed, our test Tec/engineers can help determine which range your antenna is most suited for based upon its size, frequency, and desired measurements. antenna designers as a precision laboratory specializing in the testing of prototype antennas and RF devices. The test and measurement facilities feature state-of-the-art equipment/software in RF performance, Ground Soil Testing, Above is a 4-point or 4 pin Method Test Unit that I use. an actual photo at K0UO of 3 of the 40 100 foot tall antenna poles while flooded My Soil is not Constant! It has sand and Alkli, making salt water I now use a Re-entrant system of the rhombic arrays which is 90% efficient by re-phasing the power back in the antenna, instead of heating up termination resistors. The K0UO antenna farm is now the largest in the world using wire arrays. https://static.wixstatic.com/media/77aad9_941ef65723ac46a6bfa59e340cde2816~mv2.png Model of a rhombic with real time view 3 Wave per side Rhombic 10MHz Rhombic data A polar plot illustrating antenna radiation patterns, with key performance metrics such as maximum gain, beamwidth, and front/back ratio detailed in the accompanying analysis window. L. B. Cebik, W4RNL modeling This is for 80 meters, it would need to be a half wave high to control ground loss Performance Analysis of 3.5-MHz Antenna Arrays: Comparing Gain, Angle, and Beamwidth for Single Long-Wire, V Array, and Rhombic Types, With Termination Effects on Transmission Dynamics. Performance Analysis of 3.5-MHz Antenna Arrays: Comparing Gain, Angle, and Beamwidth for Single Long-Wire, V Array, and Rhombic Types, With Termination Effects on Transmission Dynamics. Azimuth Patterns for V -Beams unterminated and terminated Diagram illustrating the general outline and azimuth patterns of unterminated and terminated V-Arrays with 4-wavelength legs at 3.5 MHz, showing differences in signal propagation. Rhombic Array Patterns, this 80 meter array is low and has ground loss Rhombic Array Patterns, this 80 meter array is low and has ground loss https://antenna2.github.io/cebik/content/ao/ao11.html Does NEC5 model buried conductors The NEC5 model does not explicitly mention the burial of conductors. A Beginner’s Guide to Modeling with NEC Part 1 WA7ARK recommends NEC5 (newer MOM algorithm) from Lawerence Livermore Labs greatly adds to modeling capability (adds buried conductors) and makes it much easier to write models (many less restrictions compared to NEC2d) Models vs. Prototypes: Why Field Adjustment Will Always be Necessary L. B. Cebik, W4RNL https://www.antenna2.net/cebik/content/amod/amod130.html TO SEE the complete Blog list check @ https://www.k0uo.com/k0uo My Corporation has checked 1000s of RF site https://en.wikipedia.org/wiki/RSI_Corporation https://www.rsicorp.com/ View of Steve Walz's of other businesses , Borderline Electric and Borderline Two-way Radio service part of RSI Corp Kiowa, KS I have founded many groups over the years My team at RSI Corp. - Radiofrequency Safety International has a proven, a successful track record in providing certified EME/RFR compliant surveys, safety training, and solutions to thousands of industry and RF Telecom workers. RSI courses also meets the certification requirements for AT&T, Verizon, Bechtel, DOD, Motorola, Black & Veatch and most other major carriers and contracting organizations. Our authorized OSHA outreach trainers have decades of real world experience to deliver the safety solutions to organizations to comply with OSHA, FCC, EPA, and FAA regulations, while also ensuring employee safety. https://www.rsicorp.com/safetytraining View of General Steven "Steve" Walz, K0UO a photo at NWOSU Alva, OK, General Steven Walz, Overview: now Retired: Civil Air Patrol (CAP), 35 year member of MARS Military Auxiliary Radio System serving in both U.S. ARMY and later the U.S. Air Force program, Security Clearance, Founder of RSI Corp, Borderline Economic Development, RSI Wind, RSI Two-way radio (Kenwood & Icom), Borderline Electric, KPAK FM, Walz Farms, proudly serves on a number of Boards over the years, Technical advisor for Concrete Walz Fencing, Published in various trade journals and author of a number of white papers. FCC Commercial License Examiner from ETA, Life ARRL member, ARRL Volunteer Consulting Engineer If you or your group has a project, just let me know, Steven Walz The K0UO antenna test range site serves as an invaluable learning environment specifically designed for a variety of Scientific, Technical, Engineering, & Mathematics (STEM) antennas projects, in an outdoor real world location. Known as"The K0UO & RSI Corp Antenna University". This unique facility provides students, researchers, and professionals with the opportunity to engage in hands-on experiences that are crucial for understanding the complexities of antenna design, testing, and implementation. Purpose and Importance of the K0UO Antenna Test Range: The primary purpose of the K0UO antenna test range is to facilitate practical learning experiences that complement theoretical knowledge. By offering a real-world setting, the site allows participants to observe and interact with antenna systems in various conditions, which is essential for grasping the principles of radio frequency (RF) communications and signal propagation. The site can be used for RDT&E antenna characterization. Features of the Test Range: The test range is equipped with state-of-the-art technology and resources that enable a wide array of experimental setups. Participants can utilize various types of antennas, including directional, omnidirectional, and specialized antennas, to conduct experiments that test their performance under different scenarios. The outdoor location is particularly advantageous as it mimics the actual environments where antennas will be deployed, allowing for more accurate data collection and analysis. ## Educational Programs and Workshops In addition to individual projects, the K0UO antenna test range hosts a series of educational programs and workshops aimed at fostering interest in STEM fields. These programs are tailored for students of all ages, from elementary school to university level, and are designed to inspire the next generation of engineers and scientists. Through collaborative projects, participants can work in teams, enhancing their problem-solving skills and encouraging innovative thinking. Research Opportunities: The site also serves as a hub for research activities, where academic and industry professionals can conduct advanced studies related to antenna technology. This includes exploring new materials, designs, and applications for antennas in various fields such as telecommunications, aerospace, and environmental monitoring. The collaborative nature of the test range encourages the sharing of knowledge and resources, leading to advancements in technology and methodology. Community Engagement: Furthermore, the K0UO antenna test range actively engages with the local community, offering outreach programs that promote STEM education. By partnering with schools and community organizations, the site provides resources and support to inspire young minds to explore careers in science and technology. This engagement not only enriches the educational landscape but also helps to bridge the gap between academia and the community. In summary, the K0UO antenna test range is more than just a testing facility; it is a comprehensive educational platform that plays a vital role in advancing knowledge and skills in the fields of science, technology, engineering, and mathematics. Through its hands-on approach, state-of-the-art resources, and community involvement, it significantly contributes to the development of future innovators and leaders in the STEM disciplines. an actual photo view of a field training class, RSI was originally a University based organization located at Northwestern Oklahoma State University, operating under a public-private partnership (RSI Educational Foundation, in 1997 Steve wrote the book, "Superior Survey Techniques". Mobile Radio Technology (MRT) magazine featured RSI Corp and Steve Walz's in an RF Survey article, which outlined the requirements on how to conduct non-ionizing radiation Radiofrequency Safety Maximum Permissible Exposure (MPE) analysis, using scientific best management practices. This document set the standard for legally documenting and substantiating compliance. Steven Walz Teaching at NWOSU 2004 at the Radiofrequency Safety International's class room located in Vinson Hall RSI and Steve Walz is training a student in RF Surveys, the student is holding the text book "Superior Survey Techniques" written by Steve Walz Gold Standard RF Surveyor Certification Class The RSI Superior Survey Techniques™ training course, by Steven Walz is a University based program developed over a quarter of a century ago by RSI. RSI is the original RF safety expert and wrote the book on RF surveys which is now an industry standard and best practice. This course is the advanced application of scientific sampling techniques necessary for professional health and safety hygiene reports. Participants must be highly qualified and it is strongly recommended attendees have ongoing compliance programs and hold certification such as RSI’s Train the Trainer or Advanced Train the Trainer or an equivalent. RSI Corp: Superior Survey Techniques This tried and true scientifically based class, consists of two days of intensive training focused on industry standards for safe and technically sound RF survey data collection. RSI’s original proven training is the only hands on course available and is designed to build a solid foundation for RF data survey collection. Upon completion of this course, participants will be trained in procedures that are uniform throughout the industry, used nationally and have withstood scrutiny from a variety of governmental entities including the FCC. They will be certified RF safety surveyors. SEE https://www.k0uo.com/post/mastering-antenna-gain-testing-techniques-for-testing-high-frequency-antennas OVERVIEW: My group, RSI Corp. - Radiofrequency Safety International was originally a University based organization located at Northwestern Oklahoma State University, operating under a public-private partnership (RSI Educational Foundation, in 1997 Steve wrote the book, "Superior Survey Techniques". Mobile Radio Technology (MRT) magazine featured RSI Corp and Steve Walz in an RF Survey article, which outlined the requirements on how to conduct non-ionizing radiation Radiofrequency Safety Maximum Permissible Exposure (MPE) analysis, using scientific best management practices. This document set the standard for legally documenting and substantiating compliance. The procedures has since become the standard for documenting radio frequency radiation both nationally and worldwide. Published in various trade journals and author of a number of white papers, over the years I have been honored to serve on numerous committees, boards and advisory groups ranging from technical, safety, environmental and economic development. Retired from Electrophysics Science work, which specialized in RF/EMI/EMC fields. I have also taught many types of Telecom Safety, Antenna Theory and Technical classes since the late 1990's, (over 35,000 students) live or online through RSI Corp. Other career activities and businesses ranged from Farming, Broadcasting, Oil & Gas services, Concrete Walz Brand of concrete fencing and Wind/Oil & Gas radio tower services. https://www.rsicorp.com/technical-inspections https://maps.app.goo.gl/Nm6zCyGzFTn2bfDN9 RSI Corp is a Environment, Health and Safety Firm, a comprehensive discipline and framework of regulations and best practices for protecting people and the planet by minimizing workplace hazards, preventing injuries and illnesses, ensuring environmental compliance, and managing risks like pollution and waste. It involves creating a safe workplace, adhering to laws from agencies like OSHA and EPA, training employees, and fostering a strong safety culture, for Hyperscale AI data centers and MOC. Since the 1990s, RSI Corp, located in Barber County, Kiowa, KS, has provided expert Environmental Health and Safety (EH&S) services to some of the largest AI data centers and NOCs. Their clients include Verizon, AT&T, T-Mobile, the Department of Defense, Google, UPS, and FedEx. Virtual University logo My team at RSI Corp has a proven, successful track record in providing certified EME/RFR compliant surveys, safety training and solutions to thousands of industry and RF Telecom workers. RSI courses also meet the certification requirements for AT&T, Verizon, Bechtel, DOD, Motorola, Black & Veatch and most other major carriers and contracting organizations. Our authorized OSHA outreach trainers have decades of real world experience to deliver the safety solutions to organizations to comply with OSHA, FCC, EPA and FAA regulations, while also ensuring employee safety. Virtual online training and classes since 2000 RSI Wind https://web.archive.org/web/20160219070059/http://rsiwind.com/, Walz Broadcasting, Border Line Electric, LMR Two-way radio services, and RSI "Defense Technical Information" Group which focuses on defense telecommunication command and control used by Federal Agencies and military see, https://www.rsicorp.com/dtic This class is part of the Motorola Co-op reimbursement (50%); Category 4 Education credits. Train-the-Trainer option meets RFSO. Certification curriculum, Telecom workers/supervisors needing recurrent training; companies wanting customizable plans. Widely used for carrier compliance (e.g., AT&T, Verizon). I have been very fortunate and honored to continue military and aviation experiences throughout the years, by occasionally working with a few Defense Contractors and Government Agencies. KDOT aviation education. Starting November, 2025 your local school districts can apply for high school aviation education courses that are outlined in the flyer. We have a video posted on our YouTube channel discussing these courses, that you can access here. If your school is interested in adopting an aviation education program, please feel free to either have them reach out to us or schedule a meeting and include us. With our academic partners, we can answer any questions and walk your school district through the process. We can also put them in touch with other school districts that currently have an aviation education program. These courses can be adopted anywhere, regardless of how rural or resource constrained your school district may be. There are strategies that can overcome many obstacles. Please help us spread the word. Ray Seif | Director of Aviation O: 785-296-6336 M: 785-496-8630 Kansas Department of Transportation Eisenhower State Office Building 700 SW Harrison St, 9th Floor Topeka, KS 66603-3745 https://mail.google.com/mail/u/0/#inbox/FMfcgzQcqbbRwMWhFLpslfVrhPrnRHxB?projector=1 The K0UO antenna test range site makes use of the 4KS Walz Public airport, known as "Antenna University", and its surrounding area as a practical learning environment for STEM (Scientific, Technical, Engineering, & Mathematics) antenna projects in a real-world outdoor setting. The site has a large outdoor area with a variety of terrain types for conducting user defined experiments. If your group has a University aerospace or antenna research STEM program, please let me know. The KØUO Rhombic Antenna Farm and Antenna Test Range: Home to the World's Largest amateur radio (ham), High Frequency (HF) Wire Arrays, miles of wire in the air and on the air daily. We are using AI which is now becoming an advanced tool in analyzing, developing, and expanding research in RF and antennas. 73 K0UO/V31KW Seve Walz A photo view of a press announcement from the Alva Review Courier, by Dr Dean Beran, President of Northwestern NWOSU Alva, Oklahoma on Dec 11, 2001 from page 2, about a joint effort with RSI Corp and NWOSU to do training at the NWOSU RSI offices and class rooms in Vinson Hall on campus RSI CORP conducted many Technical and Safety courses at NWOSU at their on campus classrooms in Vincent Hall SEE https://www.k0uo.com/post/mastering-antenna-gain-testing-techniques-for-testing-high-frequency-antennas https://en.wikipedia.org/wiki/RSI_Corporation
4KS Walz Airport in Kiowa, Kansas supports Antenna University’s ANTENNAS page as a real-world learning and testing environment for HF and broadband antenna systems. Located alongside the RSI Corp testing range and the renowned KØUO Rhombic site, the area showcases practical examples of long-wire arrays, LPDA/log-yagi designs, baluns, feed-lines, and receive antenna solutions. Learners and professionals can connect classroom STEM concepts to field-proven installations and operating practices. https://www.k0uo.com/post/4ks-walz-airportkiowaks
A New Higher Level Design Combination, used at K0UO HRS, USIA Arrays, and Rhombic "Multiple Unit Steerable Antenna" (MUSA) "A Stacked Curtain Rhombic HRS “Billboard” Array (a type of high-gain HF antenna combining stacked rhombic elements with curtain-style feed and a steerable HRS-like configuration) isn’t a single famous antenna by that name, but variants of this design are in use in high-performance shortwave (HF) communication and broadcasting installations — especially where long-distance skywave coverage with high directivity is needed." https://www.k0uo.com/post/current-distributed-feed-system-as-used-on-sterba-curtains-will-be-utilized-on-the-new-antenna This project is now "In the Air and On the Air". The antenna uses a distributed curtain type fed arrangement with a Traveling Wave Rhombic antenna. It utilizes a wire reflector instead of terminating resistors for direction, providing maximum front to back, and not wasting power in the terminating resistors, adding up to 3db to the antenna forward gain, and another 3db by utilizing reflectors, while also increasing the front the back ratio even higher (it is like a brick wall). This antenna is fixed at 30 degrees. but steerable, plus or minus 30° using electronic phasing. The upper Array is at about 190 feet, the lower Array is at 100 feet. This antenna is designed with steerable directivity and wave angle phasing. The main area of interest for this antenna is Northern to Southern Europe, over the north pole to Western Asia, south to the Mediterranean, Northern Africa and the Mideast.
Delta Loop beam antenna is essentially a type of quad (loop) antenna, specifically a triangular variant of a full-wave loop element. Polarization & Feed: Feeding point affects polarization (horizontal or vertical) and takeoff angle in both. Both are full-wave loop antennas (perimeter ≈ 1 wavelength) and belong to the broader family of parasitic loop arrays. Testing of both antennas in the air, shows the Delta with .2 dB to .4dB more gain. However modeling gives the Quad +.3 to .5 dB more, our tests in the far field show that this is do to the Deltas over all higher height above ground, the Quad has the lower part of its wire closer to the ground, so it has ground loss and a higher take of angle. The Real-World Difference: The difference is only about 0.3 dB. In the real world, human ears cannot detect a difference https://www.k0uo.com/post/delta-loop-beam-ham
The K0UO Remote station is unlike any other ham station globally," a statement that captures the essence of this extraordinary facility and its remarkable capabilities. This station stands out as a true gem in the realm of amateur radio, particularly as a Big Gun Mega Station, renowned for its impressive infrastructure and technological advancements and the use of AI. One of the defining features of K0UO is its ability to construct and effectively utilize the very large Rhombic and V Beams, which are specialized antenna designs known for their exceptional performance in long-distance communication. These antennas are not only complex in their construction but also require significant space and careful engineering to optimize their functionality, cost was never a factor "the goal is always max gain and F/B". K0UO Arrays and station uses FlexRadio 8600 along with the Flex 9300/ ML-9600 equipment, which can be used by "remote access" to the K0UO facility for DXing, casual amateur radio operation, or major contest participation, (including Multi-Operator, Multi-Transmitter or MM). In a standard 6-band contest (160m, 80m, 40m, 20m, 15m, 10m), a Multi-Multi station operates as using K0UO's Flex radio equipment and amplifiers, advanced AI control systems, for 6 independent stations running at the same time. Using K0UO's dedicated, massive directional antennas (like Rhombics, V beams, four squares, LPDA type Yagis, stacked or phased Delta loop beams quads) for each band, often placed hundreds of feet apart to prevent interference between the different transmitters In connection with this access. emote Operators can now effortlessly control this world-class "Big Gun" Mega station situated at a perfect, quiet ranch location. With the help of K0UO's AI advanced remote operation, hams can engage in Contesting, casual QSOs, or serious DXing from virtually anywhere, overcoming the limitations of local antenna restrictions, noise, or geographic disadvantages—all with AI control from your own QTH. This is the most sophisticated Remote Ham site available, featuring the very user-friendly Flex systems with full AI control, and offering numerous interactive tools, such as real-time spotting and real-time band propagation conditions, through a private proprietary program similar to those used by DOD and commercial groups. In fact at this time the K0UO site is being used for a DOD project with the Flex ML-9600 radios, and the proprietary program. https://www.k0uo.com/post/using-the-k0uo-site-remotely
K0UO using real time data with AI Integration for analyzing DX cluster and other data. K0UO is now using Predictive Modeling: Operators and researchers can use machine learning models trained on decades of solar cycles, sunspot data, and real-time ionospheric sounding data. AI is no longer just a futuristic concept; it’s here, and it’s transforming ham radio in ways we never imagined. Whether you’re planning your next contest, chasing DX, or designing antennas, AI can give you that extra edge. Dive in, experiment, and see how this technology can elevate your station and operating experience! Happy hamming and may your signals always be strong! 73 K0UO Steve Walz SEE https://www.k0uo.com/post/using-ai-for-ham-radio-contest-planning-dxing-and-station-design-automation
Rhombic antennas offer higher gain and wider bandwidth than many common HF antennas but require more space. Yagi antennas provide good gain with smaller size but cover a much narrower frequency ranges. Dipoles are simple and small but lack directionality and gain. • Front-to-Back Ratio (F/B) - This is the ratio of the response in the direction of maximum gain compared to the response directly behind the antenna (at 180⁰) • Front-to-Rear Ratio (F/R) - This is the ratio of the response in the direction of maximum gain compared to any response in the hemisphere behind the antenna (from 90⁰ to 270⁰) • Standing Wave Ratios (SWR) - An efficiency measure showing the relative size of reflections and their impact on the power of the antenna and gain, The pattern of a directive antenna changes over a frequency band The power in the diversity of the large size of the array, and what you can now hear with out QSB fading, is even more gain on RX. Happy hamming and may your signals always be strong! 73 K0UO Steve Walz SEE https://www.k0uo.com/post/rhombic-high-gain-bets-beams
K0UO is involved in the "Lost Art of Rhombics", utilizing four large wire antennas at the Kansas QTH to target the eight main DX areas, with phasing for enhanced steering. These are currently the largest HF wire-type amateur radio antennas in use worldwide. K0UO designed and constructed the entire station, including the massive Rhombic and beverage antennas, conducted far field measurements, and has access to over 1,200 acres of owned or leased land surrounding the antenna farm site for far field testing. With an extensive array of towers and antennas, it is a big antenna farm. The "KING of Wire Antennas" is a K0UO type Rhombic. Each large antenna is designed for 40 meters and above, with each leg measuring 600 to 800 feet, spanning over 1200 feet from end to end of the diamond array. They each cover about 7 acres, mounted on 80 to 100-foot tall wooden power-line poles. One is even mounted on a 160-foot tower. The front-to-back ratio is formidable, exceeding +40db. These are the largest 40-meter amateur radio Rhombic antennas currently in use. Additionally, the site has three V-Beams arrays (1200 foot on each side or 1/2 of a rhombic) for more directions. "I hope others will carry on the tradition, and art of the large Rhombic Arrays in the future". SEE https://www.k0uo.com/post/the-king-of-wire-antennas-is-a-rhombic
Since the 1990s, RSI Corp, located in Barber County, Kiowa, KS, has provided expert Environmental Health and Safety (EH&S) services to some of the largest hyperscale AI data centers and NOCs. Their clients include Verizon, AT&T, T-Mobile, the Department of Defense, Google, Black & Veatch, UPS, and FedEx. This post explores how RSI Corp supports these critical infrastructures through thorough EH&S surveys, tailored programs, inspections, and training, helping clients maintain compliance and safety in demanding environments. SEE https://www.k0uo.com/post/ensuring-safety-and-compliance-in-ai-data-centers-nocs-with-rsi-corp-s-eh-s-expertise
K0UO utilizes Ace HF Pro and IONSUM, computer programs that employ the output from the IONCAP prediction method to identify the most appropriate frequency band and necessary antenna gain under specific averaged conditions. IONSUM stands for IONCAP Summary. Propagation predictions are crucial tools for managing HF communications with DX Stations. These predictions provide data to specify the types and operating frequency ranges needed to communicate with DX by adjusting the antenna's take-off angle to maximize signal strength in the desired direction. This approach is employed to contact DX stations using either long path or short path on the F layer or to connect with North American stations during the daytime when high D Layer absorption occurs (160, 80, 60, and 40 meters). Some reflection can occur from the D region, but the strength of radio waves is diminished, leading to a significant reduction in the range of radio transmissions on lower bands during the daytime. K0UO, is integrating AI-driven real-time analysis with a commercial private network of ionosonde data to enable full-spectrum HF propagation monitoring from a single fixed transmitter location and multiple receive points Spectrum Coverage: By combining AI-driven MUF maps with the multi-point receive data, K0UO can now analyze the entire HF spectrum in near real time, identifying optimal paths and frequencies for any propagation scenario. https://www.k0uo.com/post/are-the-bands-open
At the K0UO rhombic farm and RSI Corp antenna test range site, which is the world’s largest facility dedicated to advanced antenna design and testing, engineers push the boundaries of what’s possible. Most all of the HF amateur radio Yagi beam antennas and a large portion of commercial HF beams have not been tested on antenna test ranges today. We don’t just guess antenna gain - we measure it meticulously, ensuring every antenna performs at its peak. K0UO emphasizes the scientific method: model → build → far-field test → refine https://www.k0uo.com/post/model-and-then-do-far-field-test
the K0UO station undertook a significant enhancement to its communication capabilities by installing a vertical polarized Half (1/2) Rhombic antenna, specifically designed to operate across the 40 to 6 meter frequency bands. This particular antenna configuration is known for its efficiency and effectiveness in both transmitting and receiving signals, making it an excellent choice for amateur radio operators and professionals alike. With a center height of 160 feet, the antenna of 18 wavelengths on 40 meters and is strategically positioned to maximize its range and performance, allowing for clearer communication over long distances. K0UO emphasizes the scientific method: model → build → far-field test → refine https://www.k0uo.com/post/vertical-polarized-1-2-rhombic
The Rhombic is the "PHD" of HF wire antennas With a variety of antennas available and you can use the antenna that is generally more optimum for the particular distance, direction, and time of day is better than using an amp. All the antennas at K0UO have been field measured in the Far field, so I know where the RF goes. The KØUO Rhombic Antenna Farm in Kansas, consisting of many acres, with "Miles of Wire in the Air & On the Air". Best known as an antenna Experimenter, Ragchewer 1st and DXer for fun! "It takes years of Passion, Hard work, and Commitment to build a great station". https://www.k0uo.com/post/rhombic-acres-antenna
True "Diversity Receive". It is a fantastic Improvement in reduction of QSB/fading. If one antenna is experiencing a deep fade, it is likely that another has a sufficient signal. Pattern diversity consists of two or more co-located antennas with different radiation patterns. This type of diversity makes use of directional antennas that are physically separated by some distance. Spatial diversity employs multiple antennas, usually with the same characteristics, that are physically separated from one another. Phase Synchronous Diversity Reception uses two widely spaced antennas (500 to 1500+ feet) feeding two identical high performance SDR receivers. Depending upon the expected incidence of the incoming signal, on the order of a many wavelengths. Collectively they are capable of discriminating a large portion of angle space and can provide a higher gain versus a single omni-directional radiator. This is absolutely a major Improvement, with Diversity Receive. My station uses over a mile of wire, listening to signals coming in at different angles. With the Icom 7610 and the new IC7760 using the new True Diversity Tracking Function, not just two receivers but built in Diversity, SmartDiversity™ is an improvement on basic antenna phase switching by using a microprocessor controlled algorithm to determine optimum timing for the switching activity. The algorithm analyzes both the incoming RF level and the rate of change in RF level to determine the optimum timing for phase switching, and the optimum antenna phase. SEE https://www.k0uo.com/post/diversity-receive-is-used-100-of-the-time-at-k0uo
The Beverage antenna, named after its inventor Harold Beverage, is a type of traveling wave antenna that exhibits unique characteristics, particularly when compared to other antenna designs such as the fast wave Rhombic antenna. This antenna design is particularly favored in the field of radio communications due to its ability to operate effectively over long distances, making it an essential tool for receiving weak signals, especially in the shortwave bands 160 to 20 meters. beverage antennas primarily emphasize the concept of signal to noise, closely related to the Relative Directivity Factor (RDF). The RDF is described as the antenna gain in the forward direction compared to the gain in all other directions. This metric is essential as it measures an antenna's ability to concentrate its reception in a particular direction while reducing interference from other directions. I have contacted 200 countries on 160 meters, and it wouldn't have been possible without the beverage antennas. They remain my preferred antennas for my diversity receive setup on 160-40 meters. I started DXing on 160 meters in the late 1970s, and on May 21, 1981 the power limits and other restrictions were removed by the FCC on the lower end of 160 meters. Then in March 1984 the full band was opened to full power, after LORAN-A was phased out. before that it was 50 to 200 watts, with regional restrictions, and even day time only in some areas. SEE https://www.k0uo.com/post/the-beverage-antenna-is-a-traveling-wave-antenna https://en.wikipedia.org/wiki/RSI_Corporation
