The Gap uses a coax trick to simulate a center loading inductor. It has been
reported that off-resonance, high power has done some arcing and melting. It has
nothing to do with the tuner, except that with the tuner, the matching allows
you to pump that high power without the transmitter complaining to you,
enhancing the chance of meltdown. In my mind this is a limitation of 80 m on the
Gap, more than anything else.
Some have started complaining about why the ARRL allows Gap to advertise, etc.
IT'S A COMPROMISE ANTENNA. IT COVERS EIGHT BANDS. IT'S INEXPENSIVE. IT TAKES A
SQUARE YARD OF REAL ESTATE TO PUT UP. IT MOUNTS ON A $1.50 WATER PIPE. WHAT
WOULD ONE EXPECT IT TO PERFORM LIKE?
But it does work, even if it won't beat out tribanders. And you CAN use it
without a tuner.
And, if one pays attention to the true nature of the compromises (instead of
complaining about them), one can actually get somewhat better service out of it
with some tricks. Note some of the other posts in this thread.
When I was K3FKJ, living in a row house apartment in Washington DC, years ago,
and budget strapped if ever anyone was, I had a multiband (10-40, no WARC bands)
vertical (14AVQ?) up on the roof. It was a tarred-over tin roof, and I laid
radials for each band right on the tar. Nobody knew what it was, and I worked
all kinds of DX on 20 and 40, running 50 watts. It was the right antenna at the
time. Those circumstances now and I'd put up a Gap Titan. It would have the tin
roof as a ground screen, and I would get a piece of 80 meters to boot.
But I don't expect it to perform like the C31XR's, Magnum 340N, and 4 square
going up here this fall. Why should I?
Another thing, I hear stuff about people running 1000mp's at 200 watts to get 3
dB. Heavens. Talking about smoking a 2Kbux investment. But you can get 3,4,5
almost 6 dB improvement out of a vertical dipole on lowbands by putting a ground
screen under it, depending on how much copper you use. Don't buy the wire from
Radio Shack. Go to a scrap metal dealer.
- - . . . . . . - - . . . . - - . . - . .
73, Guy
k2av@contesting.com
Apex, NC, USA
----- Original Message -----
From: Jim Reid <jreid@aloha.net>
To: <amps@contesting.com>; 'Tower Reflector' <towertalk@contesting.com>; Guy
Olinger, K2AV <k2av@contesting.com>
Sent: Monday, October 11, 1999 5:00 PM
Subject: Re: [TowerTalk] GAP Titan and vswr
> On 80 using the Gap, you have to pick your 50 kHz
>window, or use a tuner (low power only).
Why low power only, or is the Gap not able to withstand
higher voltages, say up to 800 volts or so? From what has
been written about the Gap, it sounds as if it uses some
sort of "linear loading" wires.
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