The Mighty Rhombic, the King of Antennas (AD

[@jrpefx]

Hello David, John here with some old field notes from my father a Major in the U.S.Army during WW II. He informed me that during the war he was stationed in North Africa. And his job was to transmit via short wave to parts of Europe and back to New York. He told me that he would use Rhombic Antennas to do the job. One funny aside was that the local inhabitants would climb the poles and steal the copper wire that made the antenna. So he went into the town and spoke with the local leader, and made a deal, once a month the locals would get one spool of wire and they in turn would protect and leave the antennas alone. He too said that this type of antenna worked very well. Take care 73 de KM6LBW

[@tangoseal1]

Now that is an interesting story. Sometimes you just have to barter to get stability in your relationships. We still do this stuff today in military areas.

[@izzzzzz6]

Great story. Thanks for sharing. Hope Dave sees it one day. Would be great to see Dave get a few people to interview. Stories like this would be great to have on video. Do you have any other similar stories?

[@ricpla6930]

You are an excellent presenter and speaker. Clear and concise, packed full of information with no filler bs. A true teacher.

[@tom_olofsson]

You are a great commenter. Clear, concise, no butt kissing. In short, could you please comment on some of my videos. Nobody seems to get my jokes. I would appreciate a smart comment or two. 😇

[@johncliff5417]

Great video Dave. I was a "Boy Soldier" in the Brit army from 15 years old. On leaving Boys service I went to 224 Signal Sqn. to train as a "Spec Op" I had to learn all about the good old Rhombic before being allowed to use one for listening to our friends overseas on my Racal RA17 and Eddystone receivers. Years later I was experimenting with a low band VHF vertical half Rhombic. I had to make up AMU's and my version of the "Monimatch" VSWR meters to feed into mil "C45" transceivers that we used there. With a remote station up on the Danish coast and the base in Hildesheim. N. W. Germany. The vertical half Rhombics worked a treat . The normal range for a pair of C45's using elevated ground-plain antennas was 15 to 30 miles tops. The next big test for the vertical half Rhombic was out in Malaya. I was with a light Infantry Battalion out in the jungle and our communication with Brigade HQ was via a Re-Broadcast station stuck out on a mountain range miles away. The Re-bro station broke down and no coms. Luckily I had the vertical half Rombic and matching unit stached away in my vehicle bins. I asked the units signal officer for permission to get the Assault Pioneer section involved to cut me a 30 ft bamboo pole down and clear a couple of hundred feet of jungle growth down in a straight line on the correct magnetic heading. We got the antenna up and fed into a Man pack A41 radio (1 watt o/p). This was setup on the Brigade frequency direct. I sent a "Slidex" encoded message requesting to use the frequency and explained what I was using. Got the answer back that the Brigade signals officer was on his way out to me in a chopper. I got a rollicking from him because I had not put a red light on the top. My excuse was we did not have the necessary girls there for that purpose. That was the vertical half Rhombic working to a elevated ground-plain antenna over a long distance. Not bad to say I was getting payed for my hobby.

[@davecasler]

Good war story!

[@grs6262]

As a Morse intercept op, USASA, 1966-1970 we employed rhombics to listen to 'everyone' from our listening posts (small dets to large field stations) worldwide.. Our unofficial motto was; In God we trust. All others we monitor.. The rhombic tended to business.. you could hear a gnat sneeze in western china from a monitoring station in okinawa..

[@thomthumbe]

I was manager of a large antenna field that included 13 rombic’s. About half were “nested”, or a low frequency outer antenna, with a high frequency, smaller antenna nested inside the low freq antenna. Several had both a balun and a terminating resistor at both ends. Of course only one balun and terminating resistor was used at any one given time. The dual feature allowed us to use the antenna in the opposite direction. All fed with 3”, pressurized Andrew coax. Fun times! Thanks!

[@handy335]

Thanks, Dave. As another "dated" ham operator, I always enjoy your presentations. Keep up the good work. It is greatly appreciated!

[@wramsey2656]

A conductor at that height reminded me of the transmission lines i would design as a utility engineer. We would install single or double conductors as static wires on davit arms as lightning protection (not as neutral carrying conductors). At that height needless to say in the Midwest and in Georgia (i moved around in my career), lightning would take its toll on those conductors; moreover, periodically burning the conductors in two falling on the phase conductors below. We used copperweld and even ACSR which are very strong conductors. So if you plan to put one of these up in the air and live in lightning prone areas don't go cheap on the conductors, grounds, arresters, and fittings, unless you like climbing poles or towers. Great video !!!!

[@sphexes]

Dave, it was great to see the joy in your face imparting this great information. I loved the historical back story. Thank you. 73 W8XDX

[@jonthebru]

The Maui Amateur Radio Club built a rhombic at Ho'okipa every field day for decades. Everything you spoke of; the size, the gain, it was beamed straight towards North America. Sorry, no pictures I know of.

[@boulder89984]

A few years ago I could have built one. Have many friends in the utility trade and putting up poles was not a problem. Now the trucks have GPS and side trips for pet projects are now frowned upon. Your presentation was fascinating. THANKS!

[@techguy9023]

The old AT&T long lines site in the Northeast had about 16 of them . I have a drawing showing them pointed to cities around the globe. Some were 700 feet long. This was over swampy ground. Can’t imagine the gain.

[@ke4uyp]

A couple of things to consider when talking about rhombics. Even though they do produce beautiful unidirectional patterns with very high gain figures compared to say a dipole. Unfortunately compared to a multi-element cubicle quad or Yagi they actually are not that efficient. The reason is first you have the terminating resistor and in most cases that resistor consumes approximately 50% of your transmitting power and converts it into heat. Also because of the extreme length of the antenna the omnic loss through the wire are measurable and it also contributes at least a few percent of loss to heat. When you add these two losses together a typical four element yagi mono bander can actually outperform a large rhombo operating at the same height above ground that he mentions in the video that this rhombic was at.

[@wa9kzy326]

Excellent presentation, David. Somebody used to have a website that featured the history of the Chopmist Hill rhombic farm, up in the northeastern US, that was active during WWII. It was used for SIGINT work, of course. For some reason, that piece of real estate appeared to be an "RF magnet" for signals from the Nazi warriors. Most interesting was the fact that the listening post's operators called out the local utility trucks throughout the day to reposition the antenna poles to better hear signals of choice; rotatable rhombics ! Looks like the website is no longer posted, but Wiki does have a page of basic info. Thought you might find this of interest. 73.

[@moglitoashoe9265]

hello Dave i am also an avid fan of History and i enjoyed the History part of your presentation on Rhombic antennas, back in the early 1960s each time we made a trip to Manila the Bus used to travel on the Old Mac Arthur Hi-Way, the bus's route happens to drive by the Radio Veritas Shortwave broadcast Station in the town of Bulacan, incidentally the road is flanked on both sides by the Radio Veritas enormously wide acarage Antenna Farms populated with huge inverted discone HF antennas, vertically polarized wire Log Periodic antennas, Phased Vertical Towers and i believe in the distance a Rhombic antenna for the Higher SW Frequencies. Of course back then in 1964 i didnt know yet what those Several "Wire" and Tower structures were after all i was only three or four years Old but as i got Older and in my High School days up to my college years i finally realized those acres upon acres of "Wire" and several dozen Tower structures is an enormous Antenna Farm. I first got interested in amateur radio at the age of 10 years and that also helped a lot to enlighten my young mind at that time about many different HF Antenna Configurations particularly the Log periodic antennas one for each azimuth of the compass and those Huge Discone antennas along with their open Line Feeders. I just wonder if you could also give a crash course video presentation about vertical Log periodic antennas and discone antennas as well. 73s n6mmq.

[@jimjordan9173]

I remember reading a magazine article a long time ago. The author recalled that in his early years as a radio operator in the late 30s he heard a very strong signal coming from Europe. He called the station which came right back to him. He had established a QSO with Hermann in Berlin. He mentioned that he had a friend named Hermann who he went to functions at a German club in New York, and Hermann asked for more details about this. At the end of the QSO he asked for Hermann's name again to which he replied Hermann Goring. He believed that Hermann had been texting a rhombic elevated above the streets of Berlin. And that it was intended to be used to communicate with U-Boats in the Atlantic.

[@onewolf3750]

I have to call BS on that one. Goering was head of the Luftwaffe and thought he was above everyone else. Can't see why he'd have anything to do with submarines. For that matter I can't imagine his being a Ham. Can't imagine why they'd have a rhombic in the streets of Berlin before the war. whole story is just unbelievable.

[@ericdee6802]

Oustanding presentation Dave. You need air time on PBS, your own show nightly at 8:00 pm👍 just a suggestion !!!

[@fnordhorn]

Ft. Monmouth NJ (Now Closed) MARS station had one and it was set for communication with Vetnam

[@fredderf3207]

The Germans, at Stalingrad constructed a large Rhombic Antenna to establish a direct radio link with Berlin. It worked.

[@davecasler]

Do you have any more detail on that, or articles?

[@timothystockman7533]

The VOA Bethany station had a bunch of rhombics. They used a feedlne at the far end of the antenna to feed the power back in phase to the feed point so they didn't have the loss of a termnation resistor. They called these re-entrant rhombics. They were being fed initially by 200 kW rigs, so if they'd have used termination resistors they would have been huge. Another famous rhombic was erected on a hilltop and used to received TV channel 4 New York off-air at Schenectady for retransmission,

[@jimpainter9935]

I was stationed at a remote USAF receiver site in greenland. We had a field full of these pointed at Thule and Goose bay.

[@MrMmaretic]

I'm retired from FEMA we had a comm site in MI with 9 Rhombics the towers were 60' tall about an 1/8 of a mile apart with two 10 gauge steel wire on each hey were fed by no loss coax. I think five were for transmit four were for receiving, there was also two 100' tall spiral cone antennas. There was 100k Harris radios. Site on 210 acres.

[@nontimebomala2267]

Terminated Vertical Half-Rhombic ;) is also worth a look. Ah yes, the military. There was a field of HF antennas on the Naval communications station at Wai'Anae. It was a really big field of antennas. I imagine it would have been measured in square miles ;). There were some HF antennas there that were hundreds of yards long. My work had me stationed on a number of field stations back in the days of long haul HF. I always loved hiking around (yes I did say hiking) the antenna fields looking at the finest examples of the wire antenna builder's art. Brings back great memories.

[@kaysimpson]

Old Dog interesting, thanks

[@robertfallin9733]

My duty station required communication with Navy P3s and I'm wondering if our antenna field did not have a population of vertical rombics. Half wave would have fit the height and the shape fit also. Fifty year is a long time but I think we had three or four rombic appearing antennas to cover a four, eight and fifteen meg requirement. AND Brunswick was the location.

[@deandeann1541]

I used to watch p-3's flying out of Brunswick, well before the naval air station closed. Cold War anti sub duty iirc.

[@ricpla6930]

Robert Fallin hey I’m from Brunswick!

[@richardowens9061]

Thanks, for the awesome video and analysis of this classic antenna! It occurs to me that you can modify the design, somewhat, and still enjoy substantial performance by erecting a V beam antenna, instead. For 20M, you would simply arrange a 1/2 wave dipole for 160m (or, 80m long, with 40m of wire on each leg) at an angle of about 30 degrees) using three supports at 1/2 wavelength above the ground (or, about 35 feet). Terminate each leg of the antenna at the far end with a 600 ohm resistor to ground to eliminate the rear radiation lobes and feed with 450 ohm ladder line and a tuner in the shack. Of course, you still have the inherent limitation of not being able to rotate the antenna. But, in the desired direction, you can easily achieve over 10dB gain over a standard 20m dipole at the same height, along with excellent front to back ratio that could exceed 30dB! Not bad for a simple wire antenna! 73 AI4IJ

[@dStruct619]

This video popped up on my YT feed some years after you made it here in 2021, but I found it informative and really enjoy the dive back in history. Enjoying the content, thank you and 73’s.

[@dougtaylor7724]

A good friend of mine trained at a similar facility in the 50’s. He told me he still recalls the first day when the team was taken out to have a look at the horizontal antenna field. He was even more impressed when they used the antennas.

[@watthairston1483]

Great video on Rhombic antennas Dave… These are still in use on some shortwave broadcast stations. The ones near here at WWCR use a taper section at the output of the 300-ohm adjustable balun to get up to about 600 ohms (un-terminated). Switchable stubs were used to get them down to the lower frequencies. Very effective on multiple frequencies for targeted reception zones. The biggest problem is the poor birds that land on the transmission lines, burst into flames and fall to the ground setting the grass on fire. A mentor and friend of mine from long ago was John H. (Jack) Dewitt Jr (N4CBC sk). He described series arrays of end-to-end Rhomboid’s used on Long Island, NY when he worked for Bell back in the 30’s. I am told a Crosley engineer developed the idea of feeding the termination point back to the input in-phase to recover the 3 db power loss but the critical circuitry needed to accomplish this was cumbersome and complex exactly as you noted. Thanks for the post and most interesting topic. 73, de K4WRF

[@watthairston1483]

In a bit of irony, the engineer that modified the Rhombic to replace the terminating resistor with an in-phase feedback system (Clyde Haehnle) passed away the day after this video. www.radioworld.com/news-and-business/engineering-legend-clyde-haehnle-dies-at-95

[@jonyzhu6531]

Excellent explanation! You have the best antenna series!

[@davidfrantz7173]

We operate 8 Rhombic antennas at WWRB shortwave. our antennas are no less than 160 feet above ground level. You can view our antennas at www.wwrb.org, Our transmitters run at 100 kw.

[@djp2770]

This was all new to me. Great information. Thank you!

[@noncounterproductive4596]

I made a rhombic for uhf television reception long ago. Almost everybody has the space for that. I had the idea of stacking rhombics for even more gain, but did not try it.

[@TheCrunchbird]

Great video, I have the land (57 acres) in rural NE Florida. All I need now are four 100 foot towers to hold the antenna up so as to get that low angle of radiation. Maybe one day but for now its going to have to be two switched phased half wave verticals. N2SN

[@livingadamman7994]

Congrats on over 100k subscribers, well done !

[@edrodrigues3939]

During the late 1960's I ran 24/7 HF Circuits for the USAF between England and Turkey utilizing Rhombics working from 3 MHz to 35 MHz. As powerful as the Rhombic Antenna is, there were times when even the Rhombic with a 30 KW Collins transmitter tied to it had difficulty maintaining signal quality. We always found a workable frequency but it wasn't always pretty. I guess this is more of a comment on propagation than the Rhombic Antenna.

[@robertl.fallin7062]

ed Rodriguez . .. USN RADIOMAN HERE. The Mediterranean in 66 and 67 was a challenge to maintaining fleet broadcast reception. I remember one TS FLASH message that i ended up on morse thru San Francisco Nave com center in order to clear up the garbled tty message. My ship was supposed to have twelve rated radiomen, we had five! Vietnam suck manpiwer to the point of a clear danger to operations and tge US Liberty tragedy was in part due to the conditions and a shortage of radioman. Eighteen hour days were typical .

[@robertbatchelor908]

RCA had a very large antenna farm in Rocky Point, NY. There they had a number of rhombic antennas.

[@EI6DP]

Hello Dave - great video and information. I run a T2FD (squashed Rhombic) which I find great. I had difficulty finding an inexpensive 800Ω Resistor so opted for an 800Ω Non Inductive Wire Wound (Ayrton Perry) one which a company in the UK manufactured for me at the horrendous price of £50 😊. Great antenna. Photos of my T2FD are on QRZ.

[@rickgilbrt]

Very cool. Enjoyed the history lesson as well.

[@brianphillips8317]

Thank you for a considerable effort that you put into amateur radio it must take a lot of effort to make. These videos.

[@anthonycosta1776]

Hi there dave, you are a true elmer and explain things in laymans terms. I understand everything you teach. thank you and keep em coming my friend. tony k2vi

[@davidsradioroom9678]

Thanks for the video. There are four rhombics at RAF Croughton in England. I was there in the late 1970s. There were two for frequencies above 10 MHz and two for below 10 MHz. They used to receive a four-channel HR shot from Lajes Base in the Azores. Seeing your video brought back a lot of memories.

[@adelarsen9776]

This is a great video. Nice history and well done all round. Thanks Dave. Right up my street. Cheers.

[@marklowe7431]

A friend of mine worked on the Antarctic for our weather bureau. They had a massive rhombic up to comm back to Melbourne Australia. They had a storm and from all the ice the antenna collapsed. He said even coiled on the ground and a little matching it still worked the target.

[@davecasler]

When the soil is very poor and rocky, the "apparent depth" of ground is lower and so an antenna laying on the ground can act like it's several (or even several dozen) feet in the air.

[@bassdowg]

Outstanding video shipmate , yes i Love it when U include some History about Antennas and HF Radio as a whole. Bravo Zulu

[@TheBubbaMan]

Thank you for expanding my knowledge base.

[@KX4UL]

Wow! Really good video. And what an antenna!! Good info Dave. Thanks!

[@bobcrunch]

Long-time DX king W6AM had an antenna farm of rhombics high in the Palos Verdes Estates hills overlooking the Pacific Ocean. His only rival was a W1 (don't recall full call) on the East Coast. W6AM was a retired ship's captain who died in the early 1960s.

[@davecasler]

I wish I'd have met him. He died in 1985. I worked in nearby Torrance for Northrop 1980 to 1983, and we had mutual acquaintences.

[@bobcrunch]

@@davecasler -> Some EME operators use rhombics. At VHF, a reasonable size rhombic will fit on a city lot (just be careful not to fry your neighbor). When pointed at a rising or setting moon, they provide around a 20 db gain using ground reflection. The only downside is that it's only horizontally polarized. I was off on W6AM. I was out of ham radio for a couple of decades, and was re-licensed in 1980. When he died, his property must have been worth a bundle!

[@thevacuumtubejunky9774]

Great video Sir. Thank you , very interesting antenna physics covered in your show. Thanks for sharing Kind regards Eric Dee.

[@russbellew6378]

In the 1980s I was a vendor to AT&T of test equipment. I visited the Fort Lauderdale receiving site of their WOM high seas HF radiotelephone service several times. (The remotely controlled 10kW transmitter site was about 30 miles south of the receiving site.) Both sites used switchable multiple rhombic antennas and steerable log periodic arrays. The antenna farms occupied many acres that were littered with poles and towers. WOM was the most impressive full duplex HF station that I've seen. Soon afterward satellites made it redundant - but what will we do if the satellite infrastructure fails??

[@thirtycrows]

Terrific video on antennas and history. Thanks and 73.

[@pandjnixon]

Hi David, just wondering if you could use two adjacent parallel low hills, and suspend the rhombic horizontally, out over the valley between the two hills, using copper wire for the rhombic, attached at the corners, the resistor, and the feed point via egg insulators, where the other side of the egg insulators are attached to say 3 or 4mm galvanized wire guy ropes, where a total of 6 guy wire ropes would be employed, all on the same horizontal plane as the rhombic, so that two opposing guy wires from opposite hills, would be used to tension either end of the rhombic, whilst two pairs of guy ropes; one pair each respective to either side of the rhombic; each end from opposite hills, would converge in Vee formation; where the apex of each Vee would attach onto either side of the apex of the rhombic corners (via an egg insulator, and then tensioned, to implement the sideways spread of the rhombic ? Also would the presence of the wire rope guys, be detrimental to the antenna's performance, as well as possibly needing additional egg insulators to divide the guys into non resonant lengths ? A ZL2TQA suggestion and inquiry.

[@sethlavinder]

Just watched a phenomenal 1984 interview of W6AM , man that switching system is beautiful! I would really like more information on how that worked! I only want to switch a couple open ladder line feeds but want to over build it to tolerate double the possible high voltage on the lines

[@TheCritter001]

I think the relay setup is illustrated in the Jan Perkins book.

[@DaveJohnsonad5nm]

What a fantastic idea for 2200m and 630m. Real estate is not an issue here as my backyard is a tad over 15 sq miles, yes, I said miles. However, at 8000' asl wind is a credible issue with 50-70 mph sometimes 90 mph I would want to keep things at or below 50' agl. Our soil here is saline rich so there are some blessings to be had. I think I'll give the idea some serious thought. I met Don a couple times at Dayton and was privileged to be invited to the wire ranch while stationed at Camp Pendleton. Any suggestions or thoughts on this prospect is of course welcome.

[@MrBanzoid]

Hi Dave. Another informative video - thanks. Like you I watched the first public broadcast via Telstar. Round about that time a new pub was built near where I live. I don't know how it happened but my late father in law was asked to name it. He was an astronomer so he called it the Telstar. Another local pub is called the Astronaut, no connection though. 73 de Malc 2E0EZP

[@wa9kzy326]

Was that first Telstar video of President Eisenhower. I saw that one, when I was in grade school. It excited me to the core. Still does.

[@ke4uyp]

I doubt very seriously that in 1930 4x5 view cameras had telephoto lenses. 35 mm film was not even considered in that time. Most cameras were 8x10 in 5x7 or 4x5 in. Because of that telephoto lenses were extremely rare because the focal length has to be extremely long to get even modest magnification. For example a speed graphic 4x5 press camera,, you seen them in a million movies with the great big flash bulb reflector a telephoto lens in those days for that camera would be about times two magnification an would not produce enough spatial compression in the picture to even be noticed.

[@GreyGhost-r4z]

I so want to set one up so I can hit Indonesia from WI. Which has been pretty much impossible for the last 20 years.

[@investigatorsf]

Awesome video as always great job sir 73

[@davecasler]

Thank you.

[@mikesawyer1336]

Dave your a master - Love the way you explain things

[@henryjones8849]

Thank you for answering my question so fast I am quite excited about doing this but never having picked up one before it does look a little intimidating but willing to try anyway I think it'll be quite fun once I get my license

[@davecasler]

I suggest you start your antenna experience with a 40 meter dipole and go on from there.

[@TheStevieoo]

I agree wholeheartedly! I have built a lot of antennas but wouldn't tackle the Rhombic even if I had enough space.

[@fionaohanlon2805]

Brilliant, as usual! When and if we pass through and exit the predicted economic downturn, i will gratefully support your magnificent efforts to aid we noobs in our quests for Ham licensure to the furthest extent of my ability. Thank you again sir.

[@ehayes5217]

Great presentation & very, VERY interesting, not just re the antenna but the historical info, too! 73 de WA4ELW

[@russellhueners8499]

Hugh antenna farm akrotiri Cyprus, they had rhombics and other hugh long haul HF antennas, I used them during phase three rehome tests for the USAF while in Japan in 1976

[@davecasler]

I'd love to try rhombic someday!

[@hedgerowpete]

That was an amazing idea and a great video, loved it, i liked the way you explained its plus points as well as its negative, but i will still need a lorry win to set one up

[@TheVeloking]

Dave, you should have discussed the v beam. Half a rhombic, almost as much gain. Because of the shape you can set up multiple long wires into a switching system to turn directions.

[@acestudioscouk-Ace-G0ACE]

Interesting stuff! My land plot has the length but nowhere near the width to achieve the rhombic shape. Perhaps a loop of some kind?

[@Old_Foxy_Grandpa]

Never heard or it? It's my favorite antenna. When I was a kid, I visited the AT&T ship to shore facility north of SF. A forest of rhombics. When I went in the building in the center, it was full of Collins S-Line gear. I damn near peed in my pants.

[@robertl.fallin7062]

Love the history . .

[@kenirwin276]

I've always been fascinated by the rhombic. Living in Cincinnati where the Voice of America Bethany Station was. They used what was called a recumbent rhombic. How is that different?

[@davecasler]

I'm guessing one end lower than the other???

[@johnpeterson7264]

Great video. I love the history !

[@victoryfirst2878]

This is a great video with some history to boot. Must be nice to have money too.

[@bhupendrajoshi5446]

Very precious information from history.

[@linallenm0tcf144]

Nice video Dave, many thanks for an interesting take on what is now a rather obscure antenna - I'm very tempted to try and set one up for a JOTA station :) 73 de M0TCF

[@PatAutrey]

Do you know if a 2 m half Rhombic antenna would require the 12 to 1 Balun / transformer Like the HF frequencies do?

[@Alfa011]

Great video! Thanks!

[@lyingcat9022]

You could probably build a large circular track with a circumference >= the longest dimension of the antenna. Then rotate the circle with some electric motor.

[@SuperAWaC]

i should pick up that antenna handbook

[@kaysimpson]

SuperAWaC I'm thinking the same thing

[@thormusique]

Took the words right out of my mouth!

[@bradenglettkd8zm69]

I have the antenna book, but most of it is indecipherable to me.

[@danialphaomega]

I have 30 acres in Mexico and this just grabbed my attention.

[@hobbified]

If you were feeling really clever you could probably do a 4:1 at the antenna, use cheap 300 ohm feeder, and another 4:1 at the shack, and get a respectable match to 50 ohms. I remember hearing that the Z0 of most "300 ohm" stuff on the market is actually 250 ohms or less (which would be ideal) but even if it's really 300 that's not much mismatch. Still probably not as efficient as the DIY ladder line approach, but it has a nice off-the-shelfness to it.

[@dang25272549]

Thank you sir.

[@sblamjo]

Question - Great video! Always been fascinated by these antennas but have wondered given the length of wire whether a rhombic can be driven at low power (5w) assuming your using the shortest possible fed line.

[@dougmatthew9987]

Good video Dave. I grew up just down the street from Don's land, it was really big.

[@russellhueners8499]

Radio Relay Akrotiri Cyprus, largest in the world, good job on this one. How about the AN FL/9, elephant cage used by the security service, I was at Misawa in 1976, just as they were getting ready to decommission.

[@zsradioham]

Thanks Dave, very interesting and enjoy you videos. Keep going

[@bassplayer3974]

Enjoyed that thanks, impressive for time

[@mikedelta37]

hi dave, can you post a multiband vertical antenna that has no radials and yet have a good gain? thanks...

[@rodneyjohnson4794]

maybe a vid on 'elephant cage' antennas, too. an uncle was based in thailand during vn as a radio op. they listened to chinese tx on vlf.

[@-Mark_F]

Very interesting video. A very good teacher. I can see now how the rhombic antenna is king! TYFP! So the ARRL logo is based off of the rhombic? If so that is very cool!

[@kc5lvz]

Great video Dave

[@watsok]

Dave, thanks for the info. 900 ohms seems to be very close to a tube output impedance. Add ladder line and who needs coax and all that loss ..just use the correct original components.

[@Snarky_Radio]

yes. I was hoping to see a more practical video with you constructing a Rhombic project on your property... lol. seriously.. Nice discussion and history of the Rhombic. Imagine the fun that Don, W6AM had when he fired those antennas up on AM! I have been looking at an article in the June, 2017 QST written by Wu0I who suggests a Rhombic/Loop convertible antenna for field day. By "shorting" out the far end corner opposite the feed-line, he converts the small Rhombic into a Loop and visa versa. with a switch. Keep the great videos coming David. been a ham many years and still learning a bunch from these videos. 73,

[@johnwalter4640]

Thanks Dave, what a great video. I was a bit confused with the feed in. If I make the ladder line, do I still need the 18:1 balun or can I connect it directly to my MFJ 993 atu

[@davecasler]

Connect ladder line directly to the balanced output on the 993.

[@hipal2271]

Dave, I have the land space. I am tempted to build this just to try it. I am in the country on many acres and no HOA or city codes.

[@davecasler]

Get it up as high as you can! Note that the input impedance is about 800 ohms, so you will likely have to build a balun. Have fun! Let me know how it turns out!

[@anupamkar8813]

What is the frequency of your Ham Radio.?

[@fnordist]

you can also turn the antenna, you just have to build a round track and distribute the antenna masts on four carriages, which are connected to each other with rods. That's not that expensive

[@davecasler]

Might be less expensive to install multiple rhombics.

[@kaysimpson]

Now that I'm parked I have too many questions.. Could this be considered a partial fractal antenna? How would the capacitive effect of the vertically parallel lines in the old photo affect transmission? What changes would happen to the field if the antenna were rotated 90°, to be tall instead of wide? Thank you

[@1337flite]

I wonder if a scaled down rhombic would work at say 2 meters? Or even 70cm?

[@godinhocosta9067]

73 magazine run an article mid 80’s about the use of rhombic in the vhf-uhf range.

[@kevincorrigan1116]

Dave have you every addressed the basics on SNR ? ...thank you for all your great work

[@davecasler]

Perhaps in the General videos. I'm not sure at the moment.

[@chichimusimus7612]

Nice video Dave. Always wanted a Rhombic but never had the real estate. As to feed line matching, could one use a tapered feedline (or matching section)? bring the 900 ohms down to say 200 ohms?

[@davecasler]

I have no experience with tapered matching sections, so can't say one way or the other. The standard way would be with a balun or a matching section.

[@luckydubeinrc5165]

a yagi on topband ...lols.. the Rhombic terminating resistor is also a problem if tou run QRO 800 ohm at (hallf the power in wattage at least) now try and create 800 ohm 800 watt resisitor these days hehehe. Anyway they work great , 2m band as well and its smaller manage'able and a 50 watt resistor (carbon type) can be made up somehow. Robin VK6LK (Robin) used to run a Rhombic from his farm (blockbuster on 80m and 160m )keep in m ind he used only 400 watts max from down under.

[@jamescstanley5018]

Interesting Dave. I wonder if a 2m rhombic would work, elements about4 wave lengths long, about 30foot or so which will fit in my garden, and I can easily get it to 30 foot up in the air. Being a UK foundation Ham, I am limited to only 10 watts, I manage 70m miles on a good day, with a Diamond white stick, I wonder if I could hit Scotland, about 400 miles with it! anyway i will give it a try, and let you know! Jim M7BXT

[@woopteedeewoopteedye]

Fascinating

[@VE3IPS]

Can you show this connected to your radio and do some comparisons?

[@davecasler]

I wish I had one! These are truly gigantic antennas spread over many acres. You need deep pockets to put one of these up. So everything in the video is theoretical.