Topband: Antenna Matching Question

[Bill Wichers]

Perhaps a goofy thought, but if you don't want to go the motorized route
you could try what the electric utilities like to do with their pole-top
switches: run a rod from the device down to a ground level actuator. You
could use 60' of 1/2 inch electrical conduit or maybe aluminum rod with
a section of fiberglass rod at the top as an insulator between the rod
and capacitor. This would let you adjust the cap from ground level. All
you'd need would be some simple standoffs and other easy-to-get
materials. If you go this route, I'd make sure the couplings between
rod/pipe sections were pretty secure so that they wouldn't loosen over
time.

Regarding the motorized vacuum variable, have you tried using a
well-sealed electrical enclosure? I've been using one of the plastic
electrical enclosures with a gasketed door and I haven't had any trouble
with it. This type of enclosure is used for things like car washes where
there is a need to deal with sprays of water so it's a lot more
watertight than a hardware store "drip tight" electrical box would be.
These boxes are usually around $150 or so from electrical supply houses
but they are easy to find.

  -Bill



[snip]
> There will soon come a day when I will not be able to climb to the 60
foot
> level to adjust the matching capacitor when needed. The question is:
Can I
> place the capacitor at ground level, connected to the original feed
point
> via coax or open-wire line? Will this 60 foot line radiate? I do not
want
> to
> upset the radiation pattern of the system. I tried a motorized vacuum
> variable several years ago, but it was a high maintenance item due to
> exposure to the elements.