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Re: [TowerTalk] Any 75/40M solutions?

To: "Transpacific" <transpacific@comcast.net>,<towertalk@contesting.com>
Subject: Re: [TowerTalk] Any 75/40M solutions?
From: ersmar@comcast.net
Date: Fri, 30 Dec 2005 00:55:25 +0000
List-post: <mailto:towertalk@contesting.com>
Tom:

     You didn't say how much property you have or whether you have trees.  
Nevertheless, here are some ideas for antennas for 80/40M:

1.   Inverted L type of wire antenna.  Requires a tree or similar to support 
the vertical portion.  Total wire length would be around 67 feet for 80M, 40 
feet or so should be vertical.  Forty would look like a half-WL wire requiring 
matching element (variable cap maybe) at feedpoint.  QST and/or Antenna 
Compendium describes two-band Inv L with switchable matching network at 
feedpoint.  Needs radial wires on the ground around the base.

2.   What is supporting your Hex Beam?  If a tower, you can possibly shunt-feed 
it with a variable cap and shunt wire up the side of the structure.    Also 
requires radials.  

3.   Two crossed, inverted Vs fed with common coax.  I've modeled this for 
RACES and Field Day type operation and you can get fairly decent NVIS patterns 
on both bands and some gain on 40M.  The center support pole can be as low as 
20 feet so maybe you can mount a pole on your roof along one edge.  Definitely 
not a DX skywire, though.  Horizontal distance away from center is reduced a 
bit due to the angle of wires off the pole.  (V vs dipole.) 

4.   If trees are available, you can consider a fullwave (67 feet +/- per side) 
loop wire.  I had one in the trees around my house for nine years and it worked 
great on 80 and 40 as a cloudwarmer; got some gain on higher bands out of it.  
Fed it through a tuner with coax.  

     Except for the crossed V, I've had antennas similar to these installed at 
my QTH and all worked well for me.  And I have the wire, fiberglass poles and 
insulators for the V, so I'll have first-hand experience with that this spring.

     Good luck and let us know what you decide.

73 de
Gene Smar  AD3F


 -------------- Original message ----------------------
From: "Transpacific" <transpacific@comcast.net>
> Fellow antenna users: I just ordered a Hex Beam for 20-10. I do need to find 
> a 
> very good solution for 75/40M .I'm replacing a 75-10 vertical and I want a  
> short (not full length) wire solution. Or, if any one knows of a 75/40 
> vertical, 
> that too is an option. I'm on a city lot and my roof is very visible.
> Any suggestions?
> 
> Tom KE7BYC
> transpacific@comcast.net
> _______________________________________________
> 
> 
> 
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