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Re: [TowerTalk] Stacking Beams

To: "'Tower and HF antenna construction topics.'" <>
Subject: Re: [TowerTalk] Stacking Beams
From: "Chet" <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Thu, 15 Apr 2010 08:56:50 -0400
List-post: <">>
Don that is a fantastic 40 m beam.   I love mine.  I have had mine up 5
years with no problems what so ever but......some one posted some simple
mods that I would have made if I knew about them at the time I had it on the
ground.  You can probably google  xm-240 mods and find them or ask here on
the reflector.  I have a C31 at 90 feet and my xm-240 mounted under it at 75
on a gate that turns around the tower.   I am a contester and after running
HFTA I found that for me into Europe the best height for the 40m beam is
between 70 and 80 feet so I put it at 75 feet.  A number of people have
converted the xm-240 to a moxon style antenna.  This is a major mod. Someone
mentioned their their capacity hats had come loose.  No problem with that
here. I a about 7 miles of the atlantic and this antenna has now been
through 5 or so hurricanes Unlike the TH-7 has traps which the c31 does not
have.  F12 said I could stack  the xm-240 as close as 7 feet.

I turn the C-31 with a ham iv  and I also turn the gate with the xm-40 with
another one. This has worked out well for me.  You will absolutely love the
xm-240 when you get it in the air. Everyone I have spoken with has said
forget using the cushcraft balun and to go with a more heavy duty balun.
Unlike your TH-7, you can not reach the balun on the xm-240 from the tower.
Spend a little extra and get the 2K baluns. I don't  know if you get on 160
but the xm-240 seems to rx on 160 pretty well. 


Chet  N4FX 

-----Original Message-----
[] On Behalf Of Don Tucker
Sent: Wednesday, April 14, 2010 7:58 PM
Subject: [TowerTalk] Stacking Beams

Looking for feasibility advice.

Have one tower, a HyGain HG-70HD.

Currently have a 7 el TH7DX tribander right at the tower top with a  3 el 
A3WS duobander 8 feet above it. No noticable interactions.

Have acquired a Cushcraft XM240 2 el shorty forty. Would like to put in on 
the same mast as the latter two.

What is the best placement of the these (bottom, middle and top) and what is

the minimum separation I can get away with between them? E.G., 40 on the 
bottom, the TH7 middle and  12/17 top, or????  Or will this all be too much 
for a single HD mast/TX2 rotator?

Don W7WLL 


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