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TopBand: Inverted-L, feeding from top?

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Subject: TopBand: Inverted-L, feeding from top?
From: kiddi@marel.is (Kristinn Andersen)
Date: Wed, 29 Jan 1997 16:52:34 +0000
My short/low horizontal wire didn´t do a great job
during the CQ 160/CW last weekend.  My next plan was
to put up a half wave horizontal wire at 15m/50ft
for the upcoming topband/SSB and the ARRL DX contests.

Several of you guys have advised me against a
horizontal-only antenna for 160 and suggested an
inverted-L.  Now, the only practical way for me to
feed the inverted-L from my attic shack location
is into the horizontal part (the very end or
somewhere off the end).  I would appreciate any
comments on this, including the questions:

1. Has anyone you know done this?

2. What do I do with the bottom end of the vertical
   part?  I would think it should be connected
   directly to the radial wires I would bury in the
   ground.  An alternative is leaving the wire just
   suspended a little above the ground, but I suspect
   this will give me low current in the vertical
   section - and correspondingly low radiation there.

3. Any comments on how to feed the horizontal part?
   Tuning out reactances, etc.

4. Any comments on the desired length of each
   section?  I guess most would say "the longer the
   vertical part, the better".  I would be stuck with
   about 15m/50ft vertical and approx. 25m/82ft
   horizontal to my shack window.

5. I have space to add another top section of almost
   any length, resulting in a "T" rather than the
   inverted "L".  Both US/VE and EU would be broadside
   to this "T" (or the horizontal part of the "L").
   Any opinions on the performance of "T" vs. "L"?
   Again, any length suggestions for that one?

6. And finally there is one thing that concerns me a lot.
   Is there an RF hazard with the inverted-L?  I can´t
   see the vertical leg from my shack and there is no
   way to guarantee that kids won´t be curious and tug
   the wire.  I would assume that if I can guarantee that
   the part of the wire that is within reach is at
   maximum current, the voltage will be minimal and
   probably harmless.  I could also insulate the wire
   and hope it holds during wet weather conditions, etc.

Now, I hope I´m still within the purpose of the reflectors
with this (both words TOPBAND and CONTEST are used)!
I will summarize the answers to the lists if there is
interest.

Thanks and appreciations - 73 de Kristinn, TF3KX


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