Hi,

The purpose of the coil is the following:

1) to shunt electrostatic buildup to ground, thus protecting your
receiver.
2) to provide an impedance match from 50 ohms to the very high impedance
of an electrically short whip.
3) to make the whip appear to be electrically longer than it really is.

The coil you have is pretty robust, and looks pretty good to me. I
would clean out the cobwebs, and try it out.

Oh, receivers don't much care what you use for an antenna. A long wire
strung through the air works just fine. Directivity is useful in
extreme conditions.

-Chuck Harris

Bob wrote:
Hi,
Thanks for helping,

The coil I am concerned about is the coil that is in the attached photo. It
is the coil that is at the very bottom of the 19ft aluminum whip antenna. It
is a coil that shorts out the center to the ground right at the female
coaxial connection. (sorry, forget the part number of that). Please see
attached photo of the inner workings of the base of this antenna. My
question is do I need to rebuild this coil and what does the coil do and is
it necessary. I want to use the antenna for an all band use and get up as
high as possible as I have a good tuner.

Thank you Chuck for your comments.

I will do exactly as you suggested and clean up the existing coil and re-use
it. I suspect that coil is there from the original engineering of the omni
that included those three traps.

What would you do about those three traps? I suspect should I put them in
the air, a good wind storm would blow them down as they are very heavy. The
previous owner had replaced those three traps with a straight whip and
suggested good results. I plan to use the same whip (no traps) and tune it.
Any pros or cons in this strategy? Is this the best I can do with what I
have? Preferably I would prefer to do this as I know it is windy where I am
and do not want to keep climbing but would also like to maximize my
transmission performance and receive performance.
Thanks again for any thoughts...








"Chuck Harris" wrote in message
...
Hi,

The purpose of the coil is the following:

1) to shunt electrostatic buildup to ground, thus protecting your
receiver.
2) to provide an impedance match from 50 ohms to the very high impedance
of an electrically short whip.
3) to make the whip appear to be electrically longer than it really is.

The coil you have is pretty robust, and looks pretty good to me. I
would clean out the cobwebs, and try it out.

Oh, receivers don't much care what you use for an antenna. A long wire
strung through the air works just fine. Directivity is useful in
extreme conditions.

-Chuck Harris

Bob wrote:
Hi,
Thanks for helping,

The coil I am concerned about is the coil that is in the attached photo.
It
is the coil that is at the very bottom of the 19ft aluminum whip
antenna. It
is a coil that shorts out the center to the ground right at the female
coaxial connection. (sorry, forget the part number of that). Please see
attached photo of the inner workings of the base of this antenna. My
question is do I need to rebuild this coil and what does the coil do and
is
it necessary. I want to use the antenna for an all band use and get up
as
high as possible as I have a good tuner.

Hi Bob,

You really need to put the antenna back the way it was originally.

If you remove the traps, you will have a very short vertical whip
antenna, and your tuner will have to do alot to match it. Your tuner's
only job is to make an ugly load look nice to your transmitter. It
does nothing to improve the way the antenna looks to the transmission
line. The traps and tuning coil, on the otherhand, fix the ugly load
problem right at the antenna. They give your tuner and coax a break.

Coax, and connectors get really unhappy when you run high VSWR loads
at any kind of power. At the voltage peaks, the voltage can reach
thousands of volts in a bad mismatch condition.... BUZZZAP!...

Get yourself a copy of ARRL's Antenna book. It will better explain
what is going on with your vertical. Once you understand how the
antenna is supposed to work you can start to think about modifications.

-Chuck Harris

Bob wrote:
Thank you Chuck for your comments.

I will do exactly as you suggested and clean up the existing coil and re-use
it. I suspect that coil is there from the original engineering of the omni
that included those three traps.

What would you do about those three traps? I suspect should I put them in
the air, a good wind storm would blow them down as they are very heavy. The
previous owner had replaced those three traps with a straight whip and
suggested good results. I plan to use the same whip (no traps) and tune it.
Any pros or cons in this strategy? Is this the best I can do with what I
have? Preferably I would prefer to do this as I know it is windy where I am
and do not want to keep climbing but would also like to maximize my
transmission performance and receive performance.
Thanks again for any thoughts...








"Chuck Harris" wrote in message
...

Hi,

The purpose of the coil is the following:

1) to shunt electrostatic buildup to ground, thus protecting your
receiver.
2) to provide an impedance match from 50 ohms to the very high impedance
of an electrically short whip.
3) to make the whip appear to be electrically longer than it really is.

The coil you have is pretty robust, and looks pretty good to me. I
would clean out the cobwebs, and try it out.

Oh, receivers don't much care what you use for an antenna. A long wire
strung through the air works just fine. Directivity is useful in
extreme conditions.

-Chuck Harris

Bob wrote:

Hi,
Thanks for helping,

The coil I am concerned about is the coil that is in the attached photo.

It

is the coil that is at the very bottom of the 19ft aluminum whip

antenna. It

is a coil that shorts out the center to the ground right at the female
coaxial connection. (sorry, forget the part number of that). Please see
attached photo of the inner workings of the base of this antenna. My
question is do I need to rebuild this coil and what does the coil do and

is

it necessary. I want to use the antenna for an all band use and get up

as

high as possible as I have a good tuner.