[Antennas] QST Mobile Antenna Comparisons

DavidE Benedict iam at pmug.org
Thu Dec 20 14:55:26 EST 2007


QST Mobile Antenna Comparisons, by Rich Roznoy, k1of
November 2007 QST, PG 30, etc.

Overall, good stuff there I think. Thanks Rich.

My only negatives about the article are about the poor showing of the
screwdriver antenna used.

because, having tried & used a few mobile antennae myself, contary to k1of
findings about this one tested screwdriver antenna, my "H Stewart Designs"
Screwdriver Antenna (no longer available) out-performed the few mobiles I
have tried...but I did not thoroughly test them like k1of tested, either.

Some thoughts though...
With regard to the screwdriver type antenna (I have had 2), I notice that
the one with the larger diameter wire in the coil worked best (most other
things were equal). In fact, it was markedly better, even on the same
mount in the same place on my vehicle. I shed tears that I don't have that
antenna anymore.

With regard to the QST testing article...
I think the screwdriver antenna used was far from the best available, in
that it:
1) Doesn't have larger dia. coil wire.
2) Has a far-shorter-than-most base section. (I understand that most
radiation is from the base section of a screwdriver antenna, the whip
portion acting mostly as a "capacity hat").

Too, in Rich's testing the screwdriver's whole base section & coil was in
fairly close proximity to the body/cab of the truck. (perhaps a typical
installation, but far from ideal).
-- The best installation I have seen of a short-base Screwdriver Antenna
was a short-short one mounted to the top of a P/U cab.

I think that my screwdriver antenna is mounted closer to the ideal. It is
on a hood-high metal mount which is cantelevered out from under my sedan's
front bumper ...to keep almost all of the Screwdriver Antenna away from
body metal.

Final comment...
I would now like to see Rich test a few other Screwdriver Antennae in the
same manner as the others were tested.

What do you all think about my meanderings here...?

David B. 
W7DBH
Mobile only



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