The Amateur Amateur: Caution: Low Clearance
By Gary Ross Hoffman, KB0H
Hiding the wires behind the door gasket
Easy to understand controls: Up, Down
Now, what to do with the ka-toinger (left)?
Antennas. It's always about
antennas. As much as I gawk and drool over the latest million-mode
billion-function transceiver when it comes out, I eventually have to give
myself a hard shake and come back to reality. It's not just astronomical price
tag on the transceiver, it's that I know that even if I managed to get my hands
on one it wouldn't work without a really righteous antenna.
It's always the antenna.
I've written a lot about antennas
in the past, both fixed and mobile. If you haven't seen it yet, you might read Ka-Toing!
which is about putting antennas on my Toyota RAV4 SUV. If you'd rather not,
then here's a quick summary.
My wife Nancy and I do not use our
two-car garage as a workshop, knitting room, spare guest room, or even as a
radio shack. We use it as, well, a garage. That worked well so long as
we both owned compact cars, but when I bought a Toyota RAV4 there was some
question as to whether or not it would fit. It did (pull in very slowly, check
mirrors often), but it was obvious that I couldn't put just any old mobile
antenna on it.
My first solution was to install a
Comet 5/8 wave dual band antenna with a fold-down mount. That worked, but I
eventually got tired of getting out of the SUV and manually raising the antenna
every time I pulled out of the garage, and reversing the process every time I
returned. Moreover sometimes I had to make a quick stop to lower it before
entering a parking garage, much to the chagrin of everyone behind me.
I solved that by purchasing a
fairly short mag mount antenna at a hamfest and placing it on the RAV4. It almost
cleared the garage door (hence the "ka-toing!") but I could live with the
sound, and there didn't seem to be any damage to the door or antenna.
Right, so now we're up to date. Here's what has happened since then.
Everything seemed to go well, at
least for a while. What changed everything was that our ARES group held a Simulated Emergency Test.
I was assigned to a fire station in the St. Louis suburb of Florissant, which,
incidentally means "valley of the flowers". Well, it turns out the "valley"
part is pretty much true, but it should be "valleys" plural. And the fire
station was definitely in one of them. I was able to partially work around the
low-lying terrain by erecting a mast, but I was sorely disappointed with the
performance of the mag mount on my SUV. That wasn't crucial during the S.E.T.
but I decided that I would have to look at the matter more carefully at a later
A little bit of background here. I
had picked up the mag mount antenna at a hamfest, and it was almost certainly
from an unmarked police car. I figured that it was probably mono band, VHF-HI,
but it had seemed to work okay on UHF during my initial quick-and-dirty test.
After the S.E.T. concluded, all of the post-exercise fervor had died down and
the paperwork had been filed, I did some more extensive testing of the mag
mount antenna. The first thing that became evident was that it was undeniably
a mono bander and not a dual
bander. I'm not sure where I'd been located when I ran my initial experiment on
UHF, nor which repeater I had accessed, but the fact that I could hit it had
clearly been an aberration. Maybe I'd been parked right under the tower. But
from my driveway I could hit just about zero percent of the local UHF repeaters
using that antenna. That, too, was probably an aberration, but a much more
Then I had a second thought. Okay,
this is a mono-band VHF-HI antenna, but it's not an Amateur Radio
antenna. It's tuned to the public service portion of the VHF-HI band.
Followed by, Doh! (imagine
Homer Simpson saying it). If I was going to get any meaningful service out of
the mobile transceiver mounted in my RAV4 I was going to have to revert back to
raising and lowering the Comet 5/8 wave antenna. (It was still mounted on the
luggage rack. You've already figured out that I'm lazy.)
And being lazy, I started going
through catalogs and Web sites looking for a motorized mount for my
Comet 5/8 wave antenna. I was pretty sure that Comet Antennas made one.
I was wrong. It was Diamond
Antennas that made the motorized mount. (Reprise Doh!) Well, gosh darn,
was I going to have to buy a completely new antenna as well?
Time to read the fine print on both
the Comet and Diamond Web sites.
Hmmmm. It wasn't just a matter of
an antenna and a raising/lowering gizmo, the actual mount was a separate
item altogether. The mount included the SO-238 connector onto which the antenna
would be screwed, the feed line, and the PL-239 connector to plug into the
transceiver. Now I was looking at buying a motorized almost-a-mount, an
actual mount, and a new antenna.
More reading. Lots of it. And after
examining the diagrams with a magnifying glass, I determined (hoped, really)
that it would be possible to transfer my Comet antenna and mount to a Diamond
So I asked Mrs Santa Claus to get
me one for Christmas.
And she did. (Bless her heart.)
When the weather warmed up a bit
and the winds died down enough for me to spend more than twenty seconds
outside, I backed by RAV4 into the driveway and began the task of installing
the Diamond motorized mount on it and then moving the Comet antenna and
It took hours.
No single part of the project was
overly difficult, it's just that it was cold, my fingers were numb, and my nose
was running. I dropped tiny screws and washers on a regular basis and spent a
lot of time searching for them in cracks and crevices in the driveway or under
leaves and gumballs on the lawn.
That's the part I hate most about any
project, searching for critical parts that I've dropped.
Anyway, the Comet mounting hardware
did fit into the Diamond motorized mount, though I had to remove a nut
to get it in there. (That poor nut got a lot of workout during the adjustment
phase of the project.) The Diamond gizmo fit nicely onto the RAV4's luggage
rack. It would've been easier if I'd had four hands and six eyes, but I was
eventually able to get it snugged into place.
What really took a long time was
routing the feed line and motor switch cable into the door frame. Both the feed
line and switch cable were very thin, and what I wanted to do was to tuck them
behind the door frame's rubber gasket. I didn't want to scratch the paint on
the car or damage the gasket or wires, so I tried pressing the latter behind
the gasket with Popsicle sticks.
I broke a lot of sticks.
It did work, but I figured out way
late in the game that it was relatively easy to pull the gasket loose, tuck the
wiring behind it, and then snap it back into place. Live and learn.
Antenna mounted, wiring all done,
everything connected, it was time for the ultimate test.
Yes! The Diamond gizmo raised and
lowered the antenna on command (a button sitting near the gear shift lever).
And yes, the antenna still worked. VHF and UHF signals came booming in.
The only question remaining is
whether or not to remove the old police band mag mount. Removing it will mean
doing a lot of uncomfortable crawling around in the cargo space of the SUV, so
I think I'll leave it there. Maybe it'll come in handy some day.
You never know.