The Amateur Amateur: Caution: Low Clearance

By Gary Ross Hoffman, KB0H
February 2016

Motorized mount wires

Hiding the wires behind the door gasket

Motorized mount buttons

Easy to understand controls: Up, Down

Antenna in up position


Antenna in down position


mag mount antennas

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 date.

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 revealing one.

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. Duh!

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 motorized raiser/lowerer.

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 mounting hardware.

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.

E-mail Gary Ross Hoffman

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