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Old November 7th 06, 05:42 PM posted to rec.radio.amateur.antenna
John Smith John Smith is offline
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First recorded activity by RadioBanter: Nov 2006
Posts: 2,915
Default Whip Antenna Formula

"A. Pismo Clam" wrote in message
...
Hello All,

I have just found my old Hi-Gain mobile-mount whip antenna, circa
1980's, I'm guessing.

I have just looked at the antenna and it is made in 4 parts; the whip,
the chrome spring that the whip gets screwed into, a metal tube [with a
plastic sleeve covering it. could this be the loading coil?] and lastly,
the mag base. A small quantity of RG 58 is soldered to the underside of
the "loading coil", making a very compact antenna.

If I loosen the set screw in the base and pull out the whip, it is 28"
long; I'd like to cut it so that it will receive/resonate center of the
151-174 MHz band. where I do most of my summer monitoring, using my old
[but still working] BC 210.

How long should I cut the whip to accomplish this? Or is the whip too
short already!?

I wouldn't bother the group with such an easy question, but I don't know
where to look for the formula!

Many thanks for taking the time to respond!

Alain


Beg, borrow a swr meter! Extend/lower radiator between tests to find lowest
swr...

JS