"Bob" wrote in message ...
Hi

I was given a Omni antenna from a ham who claims the best thing since sliced
cheese. I want to use it for receive at first and when licenses come in for
transmit. I would like to transmit on as many frequencies as practical and
possible as I have a good tuner.
This is an omni, aluminum, telescopic and it 19 feet long. It has 4 ground
planes about 8 feet long.

Thats a 10-11 meter 5/8 ground plane...It can be used for casual
receiving, but how well it works will depend on the bands you use it
on. Naturally, it would be good for CB or the 10m ham band, and
probably receive ok on the higher HF ham bands, but for VHF/UHF , it
will be fairly lame. It's too long...You can try it though...

As I was cleaning it up, I noticed a coil at the base of the antenna
connecting ground to center. Right at the female connector within the base
of the antenna. There is a coil that has approx 20 windings and connects to
ground. The center also feeds to the piping that stretches the full 19 feet.
The coil is pretty rough shape.



My question is in regards to this coil. Is it necessary? What function will
it serve?

Thats the loading coil to tune the 5/8's radiator to a 3/4 wave
resonance. That gives a good match to coax.. On the band it's designed
for, that is...

I can rebuild it if need be but is that necessary?

No. Not unless it's broke..

And is 19 feet
a good length for utilizing as many useable frequencies as possible?

19 ft is appx a 5/8 wave on 10/11 meters..That antenna is designed for
a single band. It's usable for casual listening on the HF bands. You
don't really need too good a match there in order to have a decent s/n
ratio. MK