When is a Dipole a Doublet? Let's Take A Serious Look!

For years and years I used coax and chokes and all that. The first time I put up a doublet, the difference was so amazing, that I've never used coax again. My overall radiator length is 102', fed with 14 ga. 450 Ohm window-line (aprox. 70') which i run through my outside wall, terminated into 2 female banana-jacks that are mounted to a piece of plexiglas screwed to the internal sheetrock plaster-board. I have a very-short window-line jumper with male banana-jacks going to the tuner. When the antenna is not in use, I have pair of ground wires with male banana jacks that plug into the antenna for and go to a very-heavy ground buss with ground-rods outside. The center-feed is on a 50' tower side-arm. Everyone yelps about taking window line through an outside wall! My wall is stucco on chicken-wire, which I cleared away where the window-line goes through. I then formed a drip loop with the window-line, and sealed the outside with a generous amount of silicon against the stucco and part of the interior of the inside part of the wall. I checked the performance on all bands both outside and after the installation and the was NO-DIFFERENCE period. This way my balun inside and I have only coax from the tuner to the radio. I run all bands 80-10M completely with exSWR. So, try this amazing antenna--you'll love it!

The definition of resonance is when all reactances have been adjusted to cancel each other out and is purely resistive With the tuner adjusting the capacitive and inductive reactances to cancel each other out and the system is purely resistive, the tuner has tuned the system to resonance! Remember Louis Varney explained how the ASTU, antenna system tuning unit that he liked to called it tuned his antenna system to resonance

Very well explained! There has always been confusion concerning the question of "dipole or doublet"? 73!

No doubt, you are a natural teacher! 73 AF5U

THANK YOU FOR LETTING US IN WITH YOUR THOUGHTS AND IDEAS PETER! I HAVE TO USE A 2 X 10M IE 1/2WAVE OM 40M BAND. I HAD A 80M LOOP BEFORE SOME YERKS SLAUGTHERED IT WHEN THEY REBUILT THE BLOODY ROOF! 160-6M WITH 450 OHM WINDOWLINE - ABSOLUTELY AMAZING LOOP ANTENNA (83,0m or 273feet WITH 23m 450 Ohm feeder! It was Marvelouse!

Thank you for extending this.

Would it be preferable to use a measured 67ft wire section and see if ATU can tune for 80, OR use as much wire as will fit in the yard space divided evenly and use tuner? I’ve got potential for 90-100 foot run depending on how cooperative a large gumtree is! Fed with ladder line into 1:1 balun. Vk5LTD

Great video. I've narrowed down my choices of my next wire antenna to two: ZS6BKW or a doublet, which of course the only difference being one is resonant and one isn't. Decisions decisions! I have a good LDG AT-1000ProII Auto Tuner so I am leaning toward the doublet. Plan on an inverted vee configuration with about 90' for each leg. Will report back when complete.

Thanks for this Peter, I've been thinking about a doublet for a while and this has helped clarify a few points. My new shack has 150ft on either side (300ft total) available for erecting a doublet. I would only be able to raise it to 25ft at the feed point and for most of it's length but one end could go to 40+ft. I suppose the best way to find out is to try it!

It might have been nice to show the voltage maxima in a dipole. There are two of them, at opposite ends. Hence the name, di-pole. There the impedance is high. In any case, if the total length is resonant (a half-wave), it's still a dipole even if it's end-fed. A doublet is just that. Two legs. Not much else to say about it in general. An endless supply of individual cases.

Thanks for this and all your other great videos. Definitely my favorite ham channel. I am on the other side of the pond, and wish your store had a branch in USA.

First 18 seconds hilarious😊🎉😂

Great description Peter I have had an argument with my friend who seems to have it in his mind that a doublet or g5rv needs to have a specific length of coax between the ladder line and the tuner. I can find nothing to support that however this video supports my argument that there is no set amount of coax needed. I am running a standard g5rv with a 4:1 balun and about 20 feet of rg-58 into a LDG it-100 and a IC-7300 with great results. My second antenna is a zs6bkw with a 1:1 balun and it loves 40-10m . Both antennas are inverted vee configuration at 40ft at apex and 10 to 12 feet at the ends. Now if only the bands would cooperate a little better. 73 Jim ve4jim

@watersstanton Peter I love the videos! I am considering a doublet for nvis on 80m and 40m. Have you experimented with this concept? Do you have results to share?

I don’t know what kinda ladder line you have in the UK but here In the States unless it was tv dual line from the 1960-70s it’s junk. Copper clad stainless steel and the coating is a mil thick if that. Best to look at Facebook The Toad Harbor page explains how to make home made open feed line. American farm works makes electric fence ribbed isolators and 13” uv resistant wire ties a roll of 12awg solid core THHN coated copper. 500’ spool should give you 130’ each leg of the diepole and 120’ feet left over for the feed line. Add in a balance tuner like dentron super tuner and you will have the best multi band antenna KC3ONO

Please keep these doublet videos coming, Really like them and the spy vids. Reminds me of the ghost story's from one of your fellow countrymen. Thanks from Merica.

Peter, I am planning on buying a metallic narrow boat and looking forward to putting together an all-band rig (IC-7300, IC-9700 combo) on it complete with two multi-band antennas. For the HF band, I was thinking about an HF loop. For the VHF/UHF bands, a tri-band vertical and a portable Yagi for the occasion QRP with the IC-705. My questions are: what effect a large metallic surface - that the boat is - will have on SWR and radiation patterns for the loop and the vertical? Should the rig and antennas be grounded to the metallic hull? Narrow boat manufacturers recommend against using the hull as a ground for electrolytic reasons. I am a big fan of your channel and thank you for all the useful information you contribute to the art. Warm salutations from grid EL97tf

Excellent! Thank you

Outstanding 73 stay safe 🙏

Mmm Current Shoes. In seriousness: I'm not sure that you've shown that Doublets are different to Dipoles: Are Doublets not just a 'subset' of all possible dipoles? In effect, a 'better fed' dipole?