I've been using a GAP Titan for the past two years while planning my new
"hidden" antenna farm. It's an OK antenna, particularly for a temporary
solution or when you've got space restrictions or need a "view friendly"
multiband HF antenna (other multiband verticals are probably more
attractive, however.) On the other hand, the antenna has some definite
shortcomings.
Advantages: 1) covers 8 bands pretty well, 40M-10M; 2) good SWR bandwidth
40M-10M (always under 2:1, typically about 1.5:1); 3) handles legal limit
power 40M-10M; 4) no radials; 5) fairly easy to assemble; 6) pretty rugged
when properly guyed.
I've worked 15 all-time new countries on this antenna. That may not sound
like a lot, but it was from #285 to #300, many of which were rare like Heard
Island (and the sunspots have been on vacation for the past two years.) I've
done OK in contests, but only when running 1500 watts. I chalked up 600 QSOs
in 10 hours on the GAP during CQ WPX and was able to hold a frequency for
some extended runs at 120+ per hour (it helps to have a semi-rare prefix.)
The GAP has lasted through three NH winters, which says a lot.
Disadvantages: 1) poor performance on 80M; 2) can't run more than 800 watts
on 80M or 75M (less if continuous carrier); 3) counterpoise for 40M must be
free of snow and ice; 4) poor coax connection design; 5) poor standoff
insulator design; 6) self-tapping metal screws used to secure joints; 7)
difficult to install alone; 8) a guy kit is not included.
1) As others have pointed out, it's basically a dummy load on 80M. It's just
a bunch of coax coiled up inside the upper tubing, connected to a
transmitting capacitor (factory selected to match your desired center
frequency.) Bandwidth on 80M is rather narrow and an antenna tuner is not
recommended.
2) When I bought my GAP, the ads and manual did not say that you can't run
1500 watts on 80M. The manual does say you can't run legal limit in a
continuous carrier mode like RTTY, but it says nothing about intermittent
modes like CW or SSB. After I burned a hole in the internal coax, the
factory told me that you really shouldn't run over 1000 watts. However, they
were very helpful in tracking down the cause of the problem and replaced the
entire center section and coax for free (which was a bear to install.)
3) It's best to get the 40M counterpoise well off the ground. Mine was only
about two feet off the surface and used to get covered with snow or ice in
the winter, driving the SWR batty. In the summer, wet weeds touching the
counterpoise will cause SWR shifts and arcing.
4) The internal coax (thin stuff) is brought out the bottom of the tube and
just snakes across the ground to your main feed. Every year the critters
chewed through this tasty yellow coax just far enough so the antenna would
work on low power -- until I cranked up the amp and melted the last few
strands of shield braid. I finally got sick of repairing it on the fly
during contests (I used a crimp-on 'F' connector and F-to-UHF adaptor in the
dark and snow once.) I fabricated a plasict box with a female UHF connector
at the bottom of the antenna which eliminated the dangling coax.
5) The tuning element standoff insulators could use some redesign. I had
problems the first year with SWR suddenly varying wildly. It turned out that
there had been some arcing between the antenna and one of the tuning
elements. It started via a stainless steel hose clamp that held the standoff
insulator. I had positioned the clamp's tightening screw inside the standoff
insulator (instructions were unclear on this), and that made it stick out
just enough to occasionally arc to the tuning element. Eventually, a
permanent carbon path was burned through the insulator, allowing the arc to
jump from the antenna to the tuning element. GAP tracked that one down very
quickly, too, and provided me with a free replacement insulator. All I had
to do was reposition all the hose clamps to get the screws out of the
insulators.
6) As someone else mentioned, the cheap screws used to connect the elements
are for the birds. Once you use one, the hole is permanently reamed out. If
you have to unscrew the elements or the screw works loose, you have to put
in a bigger self-tapping screw.
7) The antenna is heavy and unwieldy enough that it takes two people to
mount it (it's dangeous otherwise.)
8) It's easy to guy, but no kit is provided -- even though it's an absolute
necessity.
All in all, it's what it is -- a good temporary solution, backup, emergency
antenna, WARC band antenna, restricted space antenna, etc. If you don't
expect too much from it, it will please you.
73, Dick, WC1M
-----Original Message-----
From: Martin.Gary. <n3hrt@eagle1.eaglenet.com>
To: towertalk@contesting.com <towertalk@contesting.com>
Subject: [TowerTalk] Gap Vertical
>Hi all,
>
>I'm afraid that I'm going to start a big thread with this one... I'm
>sure this has been talked to death, and in my defense I DID look in the
>archives before posting this.
>
>Here's the deal. I have about $300.00 to spend and I want to buy an
>antenna that will cover 40-10 meters. I considered a tri-band beam, but
>then I would still be looking for something for the WARC bands. Besides,
>getting a beam is just the tip of the iceberg. You still have to buy a
>rotor, and everyone knows how expensive they are. So, after looking thru
>all of my catalogs, I decided that one of the Gap verticals might be a
>good choice. I think the Titan DX is the one that would work best for
>my needs. I have a 40ft. telephone pole that I could mount it on.
>
>So, after making that decision, I starting asking around about them,
>trying to find someone who actually had one to see how they perform,
>Everyone I talked to either hates them or loves them..(none of these
>poeple have actually owned one)
>I KNOW that they fall way short of the performance of a beam, but how do
>they compare with other verticals, dipoles, etc.... Whats the real story
>with them? Are they worth messing with or what???
>
>Any comments, suggestions, or alternative ideas would be greatly
>appreciated.
>
>Martin, N3HRT.
>
>--
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