[TowerTalk] Unique Inv L...Help!

[Mark Robinson]

This will show you your input impedance if you know your antenna input
impedance and transmission line length

http://www.vk1od.net/tl/tllc.php




----- Original Message ----- 
From: "Edward Sylvester" <navydude1962 at yahoo.com>
To: <TowerTalk at contesting.com>
Sent: Thursday, 01 January, 2009 2:55 PM
Subject: [TowerTalk] Unique Inv L...Help!


> What a great group!  I have one more antenna curiosity for my second
> QTH....I work up north during the week and stay in my RV...I have the good
> fortune of having access to the tall pine trees (>100' tall).  I installed
> two antennas....
>
> The first is a Cobra Ultralite Senior (140' linear loaded, fed with open
> wire line).  This rivals some of the best antennas I have ever had.  Tunes
> 6-160m.
>
> Because the span between trees is about 300', I decided to add a second
> antenna in series to take advantage of the set up.  This second antenna is
> a LW with a total length of 300' or so.
>
> I have compared the two and I prefer the dipole.  The LW couples into
> anything electronic and I hesitate to use it because it causes
> interference.  It's also noisier and is virtually the same as the dipole,
> in terms of signal output.
>
> Hence, it's somewhat of a disappointment.  Plus, my signal on 160m is
> anemic.  Thinking I can convert this into an Inverted L for a better DX
> antenna.
>
> This would not be a resonant antenna for any specific band, as I don't
> know the exact length and I don't have access to the horizontal portion
> for pruning.
>
> I had to hire a tree climber to install these!!  I just want to work with
> what I have...
>
> Here are my thoughts....Why not bring the vertical portion of the LW to
> ground level (about 100') and attach to non resonant radials?
>
> I can feed it with 450 ohm ladderline and terminate with 4:1 balun before
> feeding it to a wideband tuner.
>
> My question is, would I maintain the valuable characteristics of an Inv L
> and would this be killer on 160m?
>
> I currently feed this same LW into a remote balun, with an effective
> counterpoise on the other terminal lug.  Only thing is that it's not a
> ground level and I have no radials, per se.
>
> Thanks for the bandwidth.  As always, your thoughts are appreciated.
>
> 73 and Happy New Year!
>
> Ed NI6S
>
>
>
>
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