The Mighty Rhombic, the King of Antennas (AD

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6 жыл бұрын

There was a time, back in the 1930s and 1940s, when the rhombic antenna was the king. A remarkable antenna that had phenomenal directivity and an extraordinarily low elevation angle made it the antenna of choice for point-to-point HF links. Here's a little history, plus an exploration using EZNEC+. Phenomenal antenna! Subscribe: / davidcasler . Ask Dave Playlist: goo.gl/inaQeB. Tip Jar: ke0og.net/tip-jar
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Пікірлер: 224

@grs6262 2 жыл бұрын

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..

@ricpla6930 4 жыл бұрын

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

@tom_olofsson 4 жыл бұрын

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. 😇

@jrpefx 5 жыл бұрын

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 2 жыл бұрын

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 Жыл бұрын

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?

@fredderf3207 4 жыл бұрын

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

@davecasler 4 жыл бұрын

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

@johncliff5417 5 жыл бұрын

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 5 жыл бұрын

Good war story!

@ke4uyp 2 жыл бұрын

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.

@handy335 5 жыл бұрын

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

@MrMmaretic 2 жыл бұрын

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.

@thomthumbe 4 жыл бұрын

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!

@jonyzhu6531 6 жыл бұрын

Excellent explanation! You have the best antenna series!

@N4KRX 6 жыл бұрын

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

@wramsey2656 2 жыл бұрын

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 !!!!

@dStruct619 3 жыл бұрын

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.

@thirtycrows 5 жыл бұрын

Terrific video on antennas and history. Thanks and 73.

@jonthebru 2 жыл бұрын

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 3 жыл бұрын

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!

@sphexes 2 жыл бұрын

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

@techguy9023 3 жыл бұрын

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.

@djp2770 2 жыл бұрын

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

@craigszwed 4 жыл бұрын

This year I put up, in my oak trees, a vertically mounted horizontally polarized quad that is about 102ft long and 50ft high, with the bottom element averaging 25ft over ground. That works out to about a 5/8 wave on 160m. I feed that with 40ft of 450 ohm ladderline from a 4:1 current balun at my outside junction/lightning/ground box. I used 65ft of RG8X between there and my TenTec 229 in the garage. I have tuned and worked 6 through 160, with 6m being under swr of 2 without the tuner. I'd send you a photo but it's hard to see in the oak trees. It's easier to watch my video about the system. Thanks for all your great videos!

@davecasler 4 жыл бұрын

Sounds like a successful antenna. Go ahead and provide the video link. I'll approve it.

@johnpeterson7264 6 жыл бұрын

Great video. I love the history !

@adelarsen9776 6 жыл бұрын

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

@thevacuumtubejunky9774 5 жыл бұрын

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

@TheBubbaMan Жыл бұрын

Thank you for expanding my knowledge base.

@bassdowg 5 жыл бұрын

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

@moglitoashoe9265 4 жыл бұрын

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.

@livingadamman7994 2 жыл бұрын

Congrats on over 100k subscribers, well done !

@Alfa011 6 жыл бұрын

Great video! Thanks!

@dougtaylor7724 2 жыл бұрын

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.

@davidsradioroom9678 5 жыл бұрын

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.

@bhupendrajoshi5446 5 жыл бұрын

Very precious information from history.

@zsradioham 6 жыл бұрын

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

@hedgerowpete 6 жыл бұрын

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

@dougmatthew9987 6 жыл бұрын

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

@kc5lvz 4 жыл бұрын

Great video Dave

@mikesawyer1336 4 жыл бұрын

Dave your a master - Love the way you explain things

@robertl.fallin7062 5 жыл бұрын

Love the history . .

@fnordhorn 5 жыл бұрын

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

@timothystockman7533 4 жыл бұрын

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,

@kengilcrest8670 6 жыл бұрын

Really good stuff. I enjoyed it.

@jimpainter9935 5 жыл бұрын

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

@watthairston1483 6 жыл бұрын

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 6 жыл бұрын

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

@investigatorsf 4 жыл бұрын

Awesome video as always great job sir 73

@davecasler 4 жыл бұрын

Thank you.

@richardowens9061 3 жыл бұрын

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

@wa9kzy326 5 жыл бұрын

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.

@ericdee6802 2 жыл бұрын

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

@dang25272549 3 жыл бұрын

Thank you sir.

@glenngoodale1709 6 жыл бұрын

very nice job

@nontimebomala2267 6 жыл бұрын

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 6 жыл бұрын

Old Dog interesting, thanks

@robertfallin9733 6 жыл бұрын

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 5 жыл бұрын

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 4 жыл бұрын

Robert Fallin hey I’m from Brunswick!

@anthonycosta1776 2 жыл бұрын

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

@brianphillips8317 Жыл бұрын

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

@woopteedeewoopteedye 2 жыл бұрын

Fascinating

@bassplayer3974 3 жыл бұрын

Enjoyed that thanks, impressive for time

@edrodrigues3939 6 жыл бұрын

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 5 жыл бұрын

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 .

@ehayes5217 4 жыл бұрын

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

@jimjordan9173 3 жыл бұрын

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 4 ай бұрын

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.

@K1QS_Radio 6 жыл бұрын

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,

@fionaohanlon2805 4 жыл бұрын

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.

@davidfrantz7173 6 жыл бұрын

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.

@TheCrunchbird 4 жыл бұрын

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

@marklowe7431 5 жыл бұрын

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 5 жыл бұрын

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.

@henryjones8849 6 жыл бұрын

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 6 жыл бұрын

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

@TheStevieoo 4 жыл бұрын

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

@jamessawyer4625 5 жыл бұрын

very nice talk. Thanks

@MrBanzoid 5 жыл бұрын

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 5 жыл бұрын

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.

@victoryfirst2878 2 жыл бұрын

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

@robertbatchelor908 10 ай бұрын

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

@chopperboi89 6 жыл бұрын

It makes me think of a lot of different antenna ideas... Also makes me wish I would win the lottery, although I'd have to play for that to happen! lol. Keep up the great work Dave. DE KD2CXU

@bobcrunch 5 жыл бұрын

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 5 жыл бұрын

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 5 жыл бұрын

@@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!

@linallenm0tcf144 3 жыл бұрын

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

@barrykery1175 6 жыл бұрын

Great informative video. I really enjoyed it. Barry, KU3X

@Old_Foxy_Grandpa Жыл бұрын

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.

@watsok 6 жыл бұрын

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.

@ahbushnell1 2 жыл бұрын

good video

@thestingyham1188 6 жыл бұрын

Dave, you' are wonderful.. you make ham more fun. What more can someone ask for?

@davecasler 6 жыл бұрын

Thank you!

@noncounterproductive4596 Жыл бұрын

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.

@TheVeloking 6 жыл бұрын

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.

@sethlavinder 3 жыл бұрын

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 7 ай бұрын

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

@danialphaomega 3 жыл бұрын

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

@russbellew6378 Жыл бұрын

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??

@russellhueners8499 4 жыл бұрын

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 4 жыл бұрын

I'd love to try rhombic someday!

@DaveJohnsonad5nm 6 жыл бұрын

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.

@SuperAWaC 6 жыл бұрын

i should pick up that antenna handbook

@kaysimpson 6 жыл бұрын

SuperAWaC I'm thinking the same thing

@thormusique 6 жыл бұрын

Took the words right out of my mouth!

@bradenglettkd8zm69 6 жыл бұрын

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

@kaysimpson 6 жыл бұрын

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

@sblamjo 3 жыл бұрын

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.

@user-ss6zt2mo1l 3 жыл бұрын

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.

@josephgomes8543 Жыл бұрын

Very cool video Dave. oh if we only had the space...and the money....and the time. HA HA Keep up the great work.

@rodneyjohnson4794 4 жыл бұрын

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.

@acestudioscouk-Ace-G0ACE 3 жыл бұрын

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

@pandjnixon 2 жыл бұрын

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.

@mikedelta37 4 жыл бұрын

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

@kevincorrigan1116 5 жыл бұрын

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

@davecasler 5 жыл бұрын

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

@russellhueners8499 3 жыл бұрын

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.

@PatAutrey 3 жыл бұрын

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

@emohruo7996 6 жыл бұрын

We were using rhombic antennas for OTC up until the 1980's down here in Australia OTC meant overseas tele communication .They were located on hundreds of acres of bushland in western Sydney on giant towers now turned into a housing estate .They certainly were the ants pants of directional antennas you mention them today and people think what the hell is he talking about .Cheers De VK2BDP Dave

@luckydubeinrc5165 2 жыл бұрын

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.

@johnwalter4640 4 жыл бұрын

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 4 жыл бұрын

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

@lyingcat9022 Жыл бұрын

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.

@hobbified 4 жыл бұрын

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.

@chichimusimus7612 6 жыл бұрын

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 6 жыл бұрын

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.

@edgardomaffia5356 5 жыл бұрын

You don't need a 16 to 1 balun. You need a 4 to 1 balun and then made 1 lambda lenght line diverging the separation, to made the adaptation from 200 to 900 ohms. I made this work for an antartic base and published it as "Balun Antartico" in my blog (In spanish. You can Googletraslate): lu1ar.blogspot.com/2016/12/balun-1-4-para-hf-de-alta-potencia.html?view=magazine