You have a lossy matching unit.
Before everyone gets all cranked up about the QST x-ray expose (and the
fact that the ARRL had a stolen piece of equipment ... another story)
lets look at what that thing is.
The Maxcom matching unit gives a fairly low VSWR from around 1 MHz to
well over 50 MHz, and is more efficient with a longer antenna (35' works
pretty well though).
I did some extensive testing with a Maxcom, including VSWR sweeps, actual
performance (compared to a comprimised antenna installation) and did some
near-field voltage measurements.
My purposes were to expose the true culprit in an extensive RFI problem
on a new class of Coast Guard Cutters. Seems the operators (boat
drivers) were blaming some computer software for their autopilot and
depth-sounder problems! Sounds crazy, but they "knew" where the problem
was.
The Maxcom is part of a comprimise antenna system. If you can't install a
resonant antenna system, you try to install a base loaded whip. If you
can't install the autotuner where it needs to be (outside the aluminum
hull, NOT inside with the radio and computer gear) then you need another
comprimise.
How did it work? The Maxcom mounted outside (remember, it's epoxy filled
... pretty well anyone-proof) performed much better than the autocoupler
(on an identical 23' fiberglas whip antenna) on every frequency tested.
Suprisingly (well, to some, not to me), the computer and flourescent lamp
noise was much lower on the Maxcom as well.
Since my intent was to get the autocouplers outside, I pulled a quick one
on those fighting me, and proposed scrapping all the autocouplers, and
instead installing Maxcoms outside. Came up with about a $2.3 million
dollar savings over a 10 year period ... and I was due a chunk of that!
Long story short, they "decided" to correctly install the autotuners
outside, where they performed much better than the Maxcom (again, no
suprise to me).
If you don't want the Maxcom, let me know what you want for it ... I'll
put it to good use in a comprimise antenna situation that will let me put
RF where it needs to be ... outside the shack!
73,
Rick, WB3EXR
On Tue, 26 Aug 1997 07:32:16 -0500 Ed Jensen <k5ed@dzn.com> writes:
>Hi Gang,
>
>I picked up a Maxcom High Speed Antenna Matcher (per label) at a local
>auction.
>I can't get it open and I can't find any ads for it in old QSTs.
>
>It has 2 terminals for the antenna and one SO239 connector for the
>coax. No
>power connection.
>
>Anybody know anything about this unit?
>
>Tnx, Ed
>Ed Jensen, K5ED, El Paso, TX <k5ed@dzn.com>
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