What are you doing with the TH-7 feedline when you are running
the boom on 40 meters? That might be the culprit.
73 de Mike, W4EF..............
----- Original Message -----
From: <K4BEV@aol.com>
To: <towertalk@contesting.com>
Sent: Sunday, February 17, 2002 7:32 AM
Subject: [TowerTalk] Too much antenna?
>
> For 40 meters I now have a HF6V @ 10 feet with 4 elevated radials for 80
and
> 40, and my TH-7 boom @ 65 feet converted to 40 with an Omega match per
N4KG.
> Rig is an IC-765. Although both antennas are tuned to the CW segment of
the
> band there is enough difference between them that I have to retune the
radio
> when changing antennas. I find an "clear" freq near the center of the
> segment, cut the power to 5w and go to RTTY mode. The 765s internal tuner
> quickly matches either antenna. I then crank it back to 100w and away I
go.
> The problem I'm having is the TH-7 conversion makes my shack RF city at
100w
> on 40m.
>
> During the ARRL DX CW contest I was S&Pn JAs on the vertical quite
> successfully until the sun was above the horizon when even the KW JAs
became
> hard to copy and they couldn't hear me at all. Still S&P I thought I heard
a
> VK5 with a big pile up going.
> I switched to the TH-7 boom, tuned it as above and got distracted by the
XYL
> for a bit. When I got back to the radio (about 5 minutes later) I could
just
> copy the VK and he was just working US west coast stations, although there
> were many east coast guys calling too. I decided to give it a shot and
> dropped my call. He came right back to me (I'm in TN) through the pile!
> During my exchange I noticed no RF at all on the monitor. I was still at
5w
> !!!
> After bit of playing I found that the monitor went nuts at 10w, but was FB
at
> 5w. I was still having trouble copying the rapidly fading JAs but they
were
> coming right back to me at 5 - 7 Watts! I had NO copy at all on the
vertical.
>
> Anyone have any idea what's going on here?
>
> I've checked EVERTHING that I can think of and everything seems fine. I
put a
> coax choke at the antenna, but it didn't make any difference at all. The
> tower's about 40 feet from the radio, the TH-7 proper and the conversion
have
> seperate RG-213 feeds with the coax shield grounded at the antenna and the
> bottom of the tower, they then run a couple of inches below the ground to
the
> shack.
>
> This thing should ROCK at 100w, but the computers won't handle it --- They
> make a thumping sound on CW and just lock up on SSB. Running QRP there is
no
> indication of a problem.
>
> Maybe this thing is just toooooooo much antenna for LP? I'm suspecting the
40
> feet from the radio is the problem, but don't have a solution. Moving
either
> the tower or the shack is out of the question.
>
> Thanks in advance for any help,
> Don - K4BEV
>
> ________________________________________________________________________
> Where do you get ICE bandpass filters & beverage matching boxes? The
> same place that pays for the hosting of this list: The eHam Store.
> Order online at http://store.eham.net.
> -----------------------------------------------------------------------
>
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>
>
________________________________________________________________________
Where do you get ICE bandpass filters & beverage matching boxes? The
same place that pays for the hosting of this list: The eHam Store.
Order online at http://store.eham.net.
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