[ICOM] AH-2B price and what I decided to do.

[D C *Mac* Macdonald]

The suitability of your choice may likely depend
upon the framing of your travel trailer.  If your
RV is of wooden frame construction you probably
won't have too much of a problem.  However,
more and more RVs (of all types) are using framing
of aluminum tubing.  In this case, I suspect that
you would be in a situation similar to that of hams
who have screwdriver or center loaded whips
that are very close to the bodies of the vehicles.
There is almost certainly a definite interaction and
and directivity that will result, plus the theoretical
(at least) blocking of signal from the portion of
the antenna where maximum radiation is supposed
to occur.

I tried a base fed, insulated 20-25 feet of aluminum
military sectional tubing mast from the tongue of a
previous aluminum framed travel trailer and could
not get successful tuning with an SGC-230 tuner.
I don't know if that "antenna" was too close to
the trailer framing or what.  Perhaps I needed to
run some wire along the ground for a counter-poise.

So far, on my newest aluminum-framed travel trailer,
I have tried the ham-stick type helically wound fiber-
glass antennas mounted to a "luggage" rail on the
top rear of my trailer.  Results on 75 meters have not
been particularly encouraging.  At Ham-Com hamfest
near Dallas in June, a local club was using a screwdriver
type antenna mounted at the top of their trailer on
a tubular mast that was bolted to the bumper.  Since
this would get the radiation above the roof of the
trailer, I suspect that I will try that method at such
time as I retire and have more time to spend using
my travel trailer.

YRMV (Your Results May Vary)!

73 - Mac, K2GKK/5
Oklaoma City, OK



----Original Message Follows----
From: "Ken Kinyon" <w7ts at comcast.net>
Reply-To: ICOM Reflector <icom at mailman.qth.net>
To: "ICOM Reflector" <icom at mailman.qth.net>
Subject: RE: RE: [ICOM] AH-2B price and what I decided to do.
Date: Sun, 5 Aug 2007 18:22:07 -0600

After looking at all the options, I decided on a 20 foot telescoping 
aluminum
flag pole that I will mount to and insulate from the substantial rear bumper 
of
my travel trailer.  I will feed it with a 3 foot wire and have the magic 23 
feet
that the AH-4 likes.  When in motion I will collapse it to give a total 
length
of 102 inches, apparently also an AH-4 Magic number.  At that length it will 
be
well below the roof of the trailer , and since the trailer is a fiberglass 
egg
for all purposes, it will think it is sitting out in the open.  When I am
stopped I can operate and be patriotic at the same time.  When the trailer 
is
not involved I will use a simple 8 foot or so whip, mounted on the tonneau 
cover
of the bed of the truck.
73 and thanks for all the advice.
Ken W7TS