K0UO overview of all antennas in use
Over the past 30 years, my focus has been on exploring the limits of high-gain traveling-wave arrays. On my Blog and QRZ profile, I’ve documented the complete modeling, far-field test data, and construction history of the antenna farm for anyone interested in the technical implementation." Steven Walz , K0UO
K0UO antennas are supported by three decades of thorough testing, modeling, and transparent documentation by RSI Corp. The past physics and engineering speak to how much gain the rhombics have.
K0UO with the RSI Corp antenna Far Field Test Range uses advanced RF measurement to confirm.
ANTENNA OVERVIEW for the primary site 1
Note: The Rhombic and V-Beam are usable on every band 160 to 6, however as showed below they are most used from 40 to 10/6 meters. K0UO with the RSI Corp antenna Far Field Test Range uses advanced RF measurements to confirm all the antenna performance, with RF surveys in the Far Field
carried out by RSI Corp
Full-sized 1/4 wave 4 Square verticals, for both 160 and 80 meters, (ON4UN/type, hanging off of the 195' tower, using elevated four 1/4 wave radials, on each vertical) with 200 tons of spent iron under the 4 Square verticals arrays.
40 - 6 meters, 40-meter resonant Rhombic traveling wave antennas have been designed, offering up to +14dB gain on 40 meters and even more on higher bands. These antennas are supported by 80 to 100-foot wooden poles. The Rhombics now incorporate a Re-entrant RF power re-circulating system, which significantly enhances efficiency to approximately 90%. This is achieved through proper impedance matching and phasing to recombine the RF power, as well as replacing the termination resistor, usable on 160, 80 and 60 meters
40- 6 meter vertical polarized Rhombic firing to Central & S America @ 160' on the main 195 foot tower, usable on 160, 80 and 60 meters
40 - 6 meters, Three 1200 foot V Beams (Vee-beam) on 75 to 100 foot wood poles
With the four rhombic arrays and three V-beams, the K0UO antennas effectively cover 14 directions, every 25°, the beam width of each array, usable on 160, 80 and 60 meters
The Rhombic has a reputation of "waking up earlier" and "going to bed later" than a yagi of the same gain.
Also High-gain directional beams & LPDA arrays
4 element full size 40 meter vertical wire beam at 100 foot, fixed on Africa
2 element 40 meter full size wire beam @ 180 foot firing west (new 2023)
40-10 meters, Distributed-fed Curtain Array (Billboard) @ 190 feet, which is the highest gain antenna at K0UO. This is the only known ham station using an electrical beam steering curtain, firing from N Europe to the Middle East (0 to 60 degrees)
HF 8 element Log-periodic Beam LPDA, yagi-style log periodic for 20-6 meters @ 195 foot
In 2022 a 100 foot hinge-over Rohn 55 was added, with a fixed wire 4 element 40 meter Delta Loop beam firing east to Africa (using a WA7ARK's model design), along with phasing of the various antennas together. Mote It started out as a six element, but the 4 element had better current in the wire elements.
The 2023 The Big project was adding a beam to the above tower project, a HF Log-periodic Beam, LPDA yagi-style log periodic 20-6 meters @ 100' on the above tower, that can be used with other LPDA as stacked and or phased.
A 160 meter loop was also added in 2023, using the support cables for the delta loop, and the 4 element 40 meter wire vertical beam, this bonus antenna is at a average height of over 100 feet, and is just a great "tool" to have at the station.
Half-wave dipoles on every band, from 160 to 10 meters which can also be SMART Controlled phased stacked, are selected as needed based on the contest and band conditions
These antennas can be Lifesavers for certain conditions
160 meters at 190 & 100 feet
80 meters at 180, 90 & 45 feet
60 meters at 160 & 60 feet
40 meters at 140 & 70 feet
30 meters at 120 & 60 feet
20 meters at 170, 130, 90, & 50 feet
17 meters at 90 & 45 feet
12 & 10 meters at 80 & 45 feet
8 Beverage receive antennas each 800' to 1500 foot long, and each are 2 wire bidirectional providing 16 directions. In the winter of 2022-23 new RX beverage antennas were added that are 1500 feet and the antennas are across the U.S. 281 Highway, just east of the QTH on the creek, with feedlines under the bridge! The K0UO Rhombic Farm is so large it has antennas on both sides of a major U.S. Highway!
K0UO antenna site number 2
(which is much larger than the original site 1), the project involves re-engineering nine X-Rombic arrays with a modern design, and strategically positioning them on a hilltop where K0UO once had a 300-foot tower. The tower's top at this location is 500 feet AGL above the surrounding ranch land, allowing for an extremely low take-off angle that is highly advantageous for radio wave propagation. This elevated position enhances the transmission capabilities significantly, enabling clearer signals and reducing interference from obstructions in the surrounding terrain. The design of these nine X-Rombic arrays features legs that are each 1200 feet long, which translates to an impressive 18 wavelengths on each of the four legs specifically tuned for the 20-meter ham band. This meticulous planning results in nearly a mile of wire dedicated to each array, ensuring optimal performance and efficiency. These arrays are designed to provide comprehensive coverage, with one array dedicated to every 20 degrees of direction, facilitating global communication capabilities. This strategic arrangement allows for seamless operation across various frequencies and enhances the overall effectiveness of the transmission system. The new site, with its advanced design and elevated positioning, absolutely dwarfs the main "K0UO Rhombic Farm," setting a new standard for amateur radio operations and significantly expanding the reach and reliability of communications for enthusiasts and professionals alike. The scale of this project not only reflects a commitment to innovation in amateur radio technology but also underscores the importance of geographical positioning in achieving superior radio performance.
This site is intended for Commercial, DoD, along with remote DX and Contest ham radio applications, positioned hundreds of feet above the surrounding ranch land, ensuring an environment free of RFI noise.
K0UO aims for both sites is for exceptional signal strength, low noise, wide-angle coverage without constant rotation, and adaptive optimization for fast-changing conditions. It is well-suited for DXing, experimentation, remote operation potential, and long-path or difficult conditions where high gain +SMART control helps. It is less oriented toward pure high-rate multi-operator contesting.
The two sites now can work together for diversity and remote access, creating a more robust and flexible operational framework.
In short, the 2026 antenna site number 2 represents K0UO’s ambitious initiative aimed at achieving even higher performance standards through the implementation of extreme height configurations, significantly larger fixed high-gain wire arrays, and the integration of advanced real-time smart control systems. This site is strategically positioned to serve as a next-level experimental and operational facility, extending the capabilities of the already substantial main station. The enhanced features of site number 2 will allow for improved signal reception and transmission, providing a critical advantage in both research and practical applications.
Site 2 is emblematic of the 2026 “next level” expansion initiative—boasting higher elevation, larger individual arrays, denser directional coverage, and a suite of more advanced automated and smart control technologies. The geographical separation of the two sites is not merely a logistical detail; it is a strategic advantage that allows them to complement each other effectively. This diversity in location enhances operational resilience and facilitates remote operation capabilities, ensuring that even in challenging conditions, both sites can function optimally and support each other’s missions.
The station leverages the available land area by implementing large arrays equipped with SMART technology control systems, which significantly enhance operational efficiency and data accuracy. These systems are designed to adapt in real-time to changing environmental conditions and operational demands, thereby maximizing performance.
Electric beamforming (commonly referred to as phased-array beamforming) allows steering a radio signal in a specific direction without physically moving the hardware.
With the Electronic beam steering, along with Power Scaling elements, enables the selection of additional arrays and electronic phase shifting as required to achieve maximum noise or QRM elimination, optimal forward gain, adjustment of takeoff angle, determination of which arrays to combine for targeting the desired DX or closer stations, and to enhance gain based on conditions.
The synergy between the two sites not only fosters innovation but also ensures that K0UO remains at the forefront of technological advancements in the field. The collaboration between these two facilities represents a forward-thinking approach to research and development, paving the way for future breakthroughs that could redefine industry standards.
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