Thanks so much to all of you who responded to my concerns about the U.S.
Towers tubular crankups and the TH7DX vs KT-34XA/KT-34A debate.
I was greatly reassured by several of the replies on the U.S. Towers
tubular, both from an engineering perspective and practical real-life
experience. To top it off, I got a good long look at an 85' U.S. Towers
tubular sporting a TH7DX about 45 minutes from where I live, on top of a
much higher hill than mine. I was mighty impressed by the engineering and
quality of construction of this tower. Even with the smaller bottom section
diameter on the 72' model, I have no doubts that this tower will handle
either of the big beams (but I'm still going to leave it cranked down
between operating sessions and whenever wind levels get above about 30
MPH.) It looks like a go on the tower.
As for the beam, although I lean towards the KT-34XA, I am concerned with
several reports that SWR can change enough under snow and ice loading
conditions to make the antenna unusable. The possibility for that happening
varies quite a lot from year to year around here. For example, during the
first three years we had our 10-foot satellite dish (cleverly hidden from
my wife, of course), I had to sweep the snow out of it maybe once per
winter. Last year, it seemed like I was down there almost every week (we
had a lot of heavy wet snow.) I can probably fabricate something on a long
pole to dust the snow off the beam elements (they'll only be 22 feet up),
but it promises to be a pain. If it's ice, I'll have to wait for it to
melt.
I did check the SWR on the abovementioned TH7, and it seemed very
acceptable to me, even though the beam was adjusted for phone. The op has
the same amp as I do. I did get one report of noise on receive for the TH7
(and the KT-34)
Probably the biggest news is that I'm going to expand the beam sweepstakes
to include Force 12. I got some very favorable reports on this one, and it
appeals to me because of the reduced weight and windload (and absence of
traps and stubs.) I don't know much about this brand (Tom is sending new
lit and I've obtained a 1994 catalog to study in the meantime), but it
looks interesting.
So... any comments from Force 12 owners? Can anyone compare the C-3 or C-4
to the TH7DX or KT-34XA?
73, Dick, WC1M
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