Topband
[Top] [All Lists]

Re: Topband: Elementary Inverted L questions

To: topband@contesting.com
Subject: Re: Topband: Elementary Inverted L questions
From: Wes <wes_n7ws@triconet.org>
Date: Thu, 25 Mar 2021 08:54:10 -0700
List-post: <mailto:topband@contesting.com>
How long is the vertical section?  The insulation should have minimal effect.

Wes  N7WS


On 3/25/2021 8:07 AM, N4ZR wrote:
I have been trying to replace my inverted L, which broke a few weeks ago, and am having all sorts of puzzlements. Please be kind - I was a history major.

1.  The inverted L broke at the turn, so I went looking for sturdier wire.  I wound up with some #14 insulated recommended by our local RF maven, and put up 140 feet initially, figuring I would prune it *up* into the CW part of the band.  Imagine my surprise when it showed up resonating at 1977 KHz (on an AA-55 Zoom).  Does insulation have such a profound effect on velocity factor?

2.  My feedpoint arrangement has 17 turns of RG-400 as a common mode choke, with the radial field connected to the RG-400 shield at the antenna end.  Initially I tried measuring the resonance without the radial connection.  No resonance and infinite SWR.  I connected the radial field (8 X 70-foot radials on the ground) and that's when I saw the 1977 KHz resonance (X crossing zero).  SWR at minimum was above 2:1.  Does this make sense?  I know the radial field is inadequate for good performance, but...


_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
<Prev in Thread] Current Thread [Next in Thread>