> Also, this project is designed to use in a mostly stationary
> situation, and I was thinking of incorporating a spring or
> something similar at the base of the antenna to minimize the
> shock to the antenna connector.
Using your idea, how about a small spring at the base, followed by a
solid-rod extension (machined brass or aluminum), with a female 1/4-32
thread at the top that you can screw a mid-band (74 MHz) duckie into? The
solid extension would "make up" the missing length of the mid-band duck to
result in a 1/4 wave at 6m - probably about 15" would be required. This
way, you'd have some flexibility at the base via the spring, and the top of
the antenna would be a duck making it a little less dangerous. You'd end up
with a more-efficient radiator by virtue of having less of it
helically-loaded. I don't have an off-the-cuff guess as far as how much
radiation efficiency you would gain. Of course, the real way to improve
performance would be to improve the "other side" (ground) of the radiator
via a counterpoise or similar.
Be careful with the spring though - you want to make sure it's shorted from
top to bottom internally with a piece of braid or something. Some cheap
antenna springs (CB-grade) have nothing shorting them.
I'd be a bit concerned about the stress on the antenna connector on the
radio though. As others have mentioned, that series of radios can have
problems at the antenna connector due to repeated flexing. Otherwise, the
MT1000/HT600/P200 series were great radios, very rugged except for the
antenna connector going intermittant and occasional problems with the flex
to the front panel/speaker/mic.
--- Jeff WN3A
