Others Hams with the Rhombic ARRAY
- skylarkcolo
- Sep 2, 2021
- 7 min read
Updated: 1 day ago
Historic Preservation: The K0UO station actively preserves and utilizes parts and insulators from legendary, historic radio arrays, including those from W6AM (Don Wallace), W7YRV Roy, BBC, Voice of America (VOA) and many others.
In the 1950s to 1970s W6AM had many 1000 footers, and one was 1500ft. In fact K0UO is still using some of W6AM's hardware on his antennas, a living memory to W6AM, On the Air Daily.
Roy W7YRV/SK had nine at one time, and he developed the X Rhombic, which he had built one for every 20 degrees, (18 total). That was a truly remarkable accomplishment for an amateur station (You must see his page, great info w7yrv.blogspot.com/2013/). It was an extreme pleasure for K0UO to meet Roy, even in his 90's, he was still an encyclopedia of knowledge when it comes to very high gain antennas. K0UO is very privileged that W7YRV has entrusted him with the parts, schematics, drawing, and photos of these fabulous antennas. https://w7yrv.blogspot.com/2013/10/other-antennas-stuff.html
W1VDE Roger in OR has six and is on the air daily, also VK3MO, and in Texas N5APR and W5BY Jeff, had a few at their ranch's, W2DGU Rich in NJ, KL7KK in AK has one along with a few VK's, and V55V (V55W) in Namibia had 2 but they are now down, and TF4M also put up a large HF one at one time.
The Old V55W station in Namibia was about the same size as my Rhombics but not as high.
Martin Walter, V51W, near Omaruru, Namibia, has spent the past 2 decades improving his station, which likely accounts for his V55V station’s increasingly better signal.
After trying all possible antenna systems, he is convinced that his wire rhombic antennas are the best choice. He uses three of them; two that are 160 meters on each leg to the US and Europe, and one with 80-meter legs, also aimed at Europe. Their gain depends on the band and can top 10 dB.
V55V was used for countless contest and DXpedition activities during the past years, but now, Walter has shut down the station and move back to Germany.
W0TEC Jack Herndon had one up in Kansas for VHF and over the air TV, in the 1950-1980s, K0UO is still using parts from that site also.
VK3MO Ian sent K0UO this overview in Aug. of 2025, "My single rhombic is still in the air and functional. My rhombic is supported on 4 X 132ft steel towers guyed with non metallic guys. The rhombics are stacked with one at 70ft and the other at 132ft. There is 550ft per leg giving a total radiating wire length of 4400ft. My original objective was to build an antenna for 20M with gain. It obviously works well on the other bands. I run open wire feeders from each end of the rhombic back to the centre where I have a large TCI balun and a tuner. I then have a 600ft run of LDF-450 Heliax back to the shack. (it is a shame to lose a dB on the feedline).
I use 2.84mm diameter hard drawn copper wire for the antenna and feedline. It has survived thirty years without breakages. I started out using stranded copperweld wire and it failed after two years. It developed rust bubbles and started breaking regularly. I pulled it down and started again with the hard drawn copper and not a single problem in thirty years. (I suspect the stranded copperweld wire may have been poor quality. I purchased it from the wireman and the results were disappointing. My rhombic is aimed at New York". 73
VK3MO His rhombic has a gain of 23dBi at a take off angle of 5 degrees on 20M and is directed at New York. The rhombic was modeled using EZNEC and it has 3dB more gain than the 5/5/5/5 yagis Both the yagis and the rhombic have a take off angle of 5 degrees which allows a comparison between the two antennas in the direction of New York. Ian sees see the 3 dB advantage which validates the accuracy on NEC antenna modelling software.
ZL6QH, the Quartz Hill User Group station based near Wellington, New Zealand, is no longer in active operation. The station ceased its original HF DX/contesting activities in 2007, and the Quartz Hill User Group was formally disestablished in 2016, K0UO has a few parts in use for that site also. The QHUG committee had been planning a new remote HF DX/contesting site to replace Quartz Hill, but after 11 years of inactivity, they decided to wind down the original station. Resources were redirected toward the RemoteDX Inc. project, which focuses on establishing and operating remote HF DX and contesting sites across the Wellington region, but not Quartz Hill.
W1AW used one single Rhombic firing west from Connecticut until the 1980s, when they replaced it with a stack of beams, however as stated in QST "They never have North Amerrican signal that had with the Rhombic". The W1AW Rhombic Bet the Beams, there are old maps showing the coverage field strength of the Rhombic, it was a short rhombic however even on 80 and 40 the U.S. signal was strong. The old ARRL W1AW Diamond Rrhombic antenna (As they called it) coverage map and signal pattern diagram originally appeared in QST Magazine around the time the historic West Hartford, Connecticut memorial station was established in the late 1930s (the station dedicated transmissions using the W1AW callsign in 1937, and the classic layout maps were featured in 1937–1938 QST articles).Map Details & Characteristics
The Concept: The sketch features a classic North American map overlay illustrating the reception and field strength patterns of the W1AW diamond rhombic antenna as it fired west from Connecticut.
The Data: It showcases indicated signal gains and relative line-of-sight losses across different states and U.S. regions, measured directly using a vintage National Company HRO receiver.
The Pattern: It provides a general overview of the antenna's directivity—demonstrating how transmission conditions and a station's precise geographic location relative to the major forward lobe or minor sidelobes affected the received signal strength on the 40 and 80-meter bands.
The K0UO site uses repurposed equipment from W6AM's old station, W7YRV, Voice of America, The BBC and other legendary stations.
From a technical and raw performance standpoint, it is the most powerful, unique, and highest-gain HF wire antenna farm still in existence anywhere in the world. While systems like RemoteHamRadio (RHR) rely on standard towers and stacked aluminum Yagi antennas, K0UO focuses on the "Lost Art" of massive, multi-acre wire arrays using the newest technology.
The Rhombic is the antenna that won WW2 for the west
"As most hams need some Game, get the Gain"
NOTE, "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 thousands of feet of wire in the air, which creates receive 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 K0UO site now employs the Re-entrant Rhombic, achieving 90% efficiency by re-phasing the power back into the antenna rather than dissipating it in termination resistors.
W6AM 1946 antenna layout below
TO SEE the complete Blog list check @ https://www.k0uo.com/k0uo
"The K0UO station is unlike any other ham station globally," making it truly unique as a Big Gun Mega Station. It is one of the few capable of constructing and utilizing very large Rhombic and V Beams, along with a variety of other antennas and AI. K0UO features the largest operational HF wire antenna in the world.
"I hope others will carry on the tradition, and art of building the large Rhombic Arrays in the future". It is truly the "PHD" of wire antennas.
Remote operation users
Note to contest operators, DXers, and remote users of the "K0UO RemoteHamRadio facility": You must sign a non-disclosure agreement and keep the "exact location" of the K0UO site confidential. The site hosts priority DOD/DOW projects using specific HF high-gain antennas. You will be notified if an antenna is unavailable, as per the original agreement, which states certain antennas are not guaranteed and may change without notice, following the Department of Defense utilization clause (30 days on most agreements).
The K0UO location owner receives many inquiries annually for remote station use for DX, casual amateur radio, or contests. Due to limited access, a protocol is required. If you have an agreement, you must comply with the non-disclosure terms. While contest location disclosure is often required, stating the station is in Grid Square EM07, Barber County, Kansas, is allowed; revealing the exact location or owner/call breaches the agreement. If approved, enjoy the station responsibly.
The facility includes valuable equipment like Flex 8000 transceivers, amplifiers, advanced control systems, and massive HF antennas, including Rhombic, V beams, Delta Loop quad-beams, and more.
The agreement is confidential, prohibiting disclosure to others. This ensures sensitive information remains protected. Each agreement is customized to meet specific needs, fostering trust and communication while safeguarding interests. Breaching confidentiality can result in legal consequences and loss of trust. Respect the agreement terms and maintain confidentiality at all times.
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