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

[Ken Kinyon]

Hi Mac,
Our trailer is a Big Foot made in Canada.  The whole strength of the structure
comes from one fiberglass tub turned upside down on top of another and fastened
along the seam. the only framing is for the interior and it is all light wood or
particle board.
73,
Ken W7TS


-----Original Message-----
From: icom-bounces at mailman.qth.net
[mailto:icom-bounces at mailman.qth.net]On Behalf Of D C *Mac* Macdonald
Sent: Sunday, August 05, 2007 19:09
To: icom at mailman.qth.net
Subject: RE: RE: [ICOM] AH-2B price and what I decided to do.


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


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