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Author Topic: efhw plus a vertical at the apex?  (Read 277 times)

KD0VE

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efhw plus a vertical at the apex?
« on: March 26, 2023, 06:11:40 AM »

When portable I usually use an EFHW in an inv L or inv V with the apex about 30.

I've been experimenting with elevated verticals with 2 radials and have been surprised at how well they work.  Physically it would be relatively easy for me to add a 10M vertical to the top of the telescoping fiberglass mast I use to get the high point for the EFHW.  I would attempt to arrange the elevated radials at right angles to the horizonal component of the EFHW.  This would require a separate feedline for the 10M.

Just wondering if there are any obvious reasons why this wouldn't work.  One question is if the 10M feedline running parallel to the vertical section of an Inv L config for the EFHW would create problems.  (This could be avoided by doing an Inv V for the EFHW)  I would never be using both at once.

Thx in advance to anyone that has insight or suggestions.
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W1VT

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Re: efhw plus a vertical at the apex?
« Reply #1 on: March 26, 2023, 06:18:35 AM »

EZNEC 7 is a great program for modeling potential interactions.  It is now free since the developer has retired and offers no support.
It can model feedline shields as a thick copper conductor.   As well as ununs and choke isolators.
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W4HRL

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Re: efhw plus a vertical at the apex?
« Reply #2 on: March 26, 2023, 06:36:32 AM »

I have a couple of thoughts for you.

While I have never used an Inverted L topped by a vertical, I have used each one separately. 

I also found the vertical with elevated radials to be a good antenna (as well as liking my Inverted L).  I ran the vertical with the feed point at about 10 feet (a longer painter's pole setup) and four elevated radials drooping down from the feed point to the top of four-foot electric fence poles.

Have you considered setting up the vertical as a separate, second antenna? You do not need the height of your telescoping mast. Getting the feed point of the vertical six to ten feet off the ground with elevated radials should give you a good 10 Meter setup.

W4HRL
Mike in Poquoson VA
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KD0VE

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Re: efhw plus a vertical at the apex?
« Reply #3 on: March 26, 2023, 08:36:54 AM »

Mike; good thought on separate antennas. I actually used a 10M elevated vertical at about 8' yesterday for a club POTA activation and was pleased with the performance.  That's what got me thinking about adding it to my usual EFHW.  I think it probably would be easier set up with them separate.
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ZL3OF

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Re: efhw plus a vertical at the apex?
« Reply #4 on: March 27, 2023, 02:36:27 AM »

If tying off radials is an issue, a homebrew 10m slimjim might be an option for you. With 1/4 wave matching section it's a little less than 7.5m long. Mounted on a 10 metre telescopic pole puts the base 2.5 metres above ground level.
Ten metres is wide open at the moment and I just worked New Zealand to Sweden with one.

Ian
ZL3OF
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