Author Topic: All Band Single Wire Antenna,The Zeppelin  (Read 46515 times)

Offline Alan Georges

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Re: All Band Single Wire Antenna,The Zeppelin
« Reply #90 on: November 11, 2018, 09:01:34 AM »
I have one question - what is the final verdict?
I've been having good luck with the 42' version while camping.  It's kind of a hassle getting it up over a limb high enough to stretch it out vertically, but with some kind of launcher it's not too bad.  Tunes and works well down to 80m, particularly well on 60m.  And of course, it just eats up the higher bands very easily in that configuration.

I've also stretched it horizontally at about 10' height and worked 80m NVIS with it.  Signal reports from ~100 miles away were that it worked, but was 10 dB down from my low NVIS dipole.  Good for a backup, so long as you're not on a QRP radio.

My favorite however is the mini 21' version.  It's much easier to hang, no launcher needed, just a good throwing arm.  It only works down to 40m, which is fine if I'm just out for an afternoon hike.

In the field, they both tune more easily and on more bands if you drape on the dirt a 17' wire off the tuner's ground lug.  If I'm in the shack testing things out, I just tie into the shack's ground.

I imagine a full 67' version is about the easiest way to get onto 160m.  Ought to give it a try this winter.

Once you've got a tuner, the actual antennas are priced in the free-to-really-cheap range.  It comes down to how much room you have, what antenna supports are there, and if you want to work vertical for low prop angles or horizontal for NVIS.  Good luck and keep us posted on how you go with this.

Offline Pabrides

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Re: All Band Single Wire Antenna,The Zeppelin
« Reply #91 on: November 12, 2018, 08:35:47 AM »
Well if no one talks me out of it I will probably go with the 67 ant + 17 ladder-line.  I will have to do a bit of research though....  everyone everywhere seems so occupied with matching elements that I cant help but wonder how one could consider a 4:1 balun adequate when matching 50 ohm coax to 450 ohm ladder-line; which equates to about 450:200 mismatch (about 113:50).  Is this considered reasonable?  in that case 75 ohm cable might be better with a 50 ohm matching section at the transmitter; 450:300 (or 113:75).  However a 9:1 balun would match the ladder-line to 50 ohm almost perfectly (BTW - doesnt 9:1 sound strangely inefficient??).  So indeed I have some reading to do about this...  One of the thread contributors stated that changing the position of his coax feeder drastically  changed the tune-ability of his trans-match - that means there was some rf on the feeder.... thats a leak which hardly contributes to radiation efficiency.  It means the trans-match or auto-tuner must be working pretty hard to keep the transmitter happy....  besides, I thought baluns were to match unbalanced feeders to balanced antennas...  How is a Zepp a balanced antenna?  Maybe this is where the 17 feet comes in...  Im open to some comments here.

Offline Alan Georges

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Re: All Band Single Wire Antenna,The Zeppelin
« Reply #92 on: November 12, 2018, 05:31:22 PM »
The original design started as a random wire with a short counterpoise, a sort of off-center fed dipole, then the counterpoise got folded along the length of the random wire, then it got turned into window line, which makes it a variant of the Zepp.  That 17' (~5 meters) piece of window line doesn't work as a transmission line here, it's more akin to a matching stub because it's so much shorter than any of the HF wavelengths.  It's going to have all kinds of crazy common mode currents running up and down the window line, but the total antenna does load up properly and radiate.  The balun connecting it to a short feed coax will keep most of that common mode junk off the coax and out of your tuner & radio, and a 17' wire on the tuner's ground lug will bleed off the rest.

This article has some measured SWR data: https://thewakesileave.wordpress.com/2016/08/15/a-42-portable-multiband-hf-antenna-with-no-wire-on-the-ground-the-w3edp-jr/ both without a 4:1 balun/unun (1st column) and with (3rd column).  The SWR numbers in the 3rd column are all within the range of most autotuners.  Without taking a deep dive into modeling the boundary conditions and radiation pattern, it's just easier to point to the SWR data and say "don't overthink this one, because it works."  And yeah, that's a total cop-out voodoo answer, but if it works and it's easy to hang up in a tree, I'll take it.  :)

It's a weird antenna, really a one-armed version of the G5RV, but that one-armed-ness is what makes it to easy to hang.  You should go for it, if it fits in your yard and the the spouse doesn't complain.

Offline Pabrides

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Re: All Band Single Wire Antenna,The Zeppelin
« Reply #93 on: November 12, 2018, 09:33:33 PM »



I looked at the link you sent and smiled at the last row...  but you just mentioned another 17 foot counterpoise at the tuner (I suppose that just gets snaked around the shack... Yesterday I bought 20 ft of ladder-line (450 ohm) at almost a dollar a foot. Ill use the extra to make a VHF J-pole or slim jim.  Ill be making my own balun for the Zepp  which will be another first.  Thanks for your time and the information.  Im just getting too old to do a lot of climbing and tinkering around... These days I want something that works the first time and every time.  I mostly had dipoles before but our new place makes one almost impossible.  I could go vertical and have considered an H-pole, however they have their own problems.  I also detest the idea of radials so an elevated H-pole, which doesnt use them, seems to be a good bet..  The Zepp seems to be very portable, which is bonus.  Ya know the worst thing about getting old is that one just cant afford the things one used to.  The price of ladder-line surprised me, but I want to try this Zepp so bad I cant see straight... Dont tell my wife... HIHI     thanks again.