"Dloyd Lavies" wrote in message
ups.com...
On Nov 4, 4:00 am, Ian Jackson
wrote:
In message om, Dloyd
Lavies writes

On Nov 3, 5:54 pm, "John Doe" wrote:
If you can't contribute anything positive to this question, then stay
out of
it, with your trash!

I have a 10m base loaded mag mount antenna, that I had to put a piece
of
felt over the magnet as not to scratch a new vehicle.

You are wasting your time trying to protect the paint when using a
magnetic mount. Grit will find its way under your magnet, and within
a year of normal driving, you will have scratched paint.

I used a 7" magmount for a 5/8 WL on 2m.
It had a rubber boot.
I used it most days to and from work, which involved putting it on and
taking it off twice each day. And then there was other use.
Each time, before I put it on, I wiped the mounting spot (in the centre
of the roof) with a soft rag (with maybe a bit of spit if nobody was
looking).
Four years later, when I got rid of the car, the mounting spot was
extremely highly polished, which (being a company car) is more than you
could say for the rest it.



--
Ian

Interesting Ian,

I suppose the fact that you removed the antenna twice a day and wiped
the spot made a substantial difference. In my experience, I did not
remove the antenna daily, but as a lot of amateurs, I used the magnet
mount in lieu of punching a hole. After a year, the paint had
terrible scratches where the magnet had been placed. Nevertheless,
this still does not solve John's problem with the detuning he is
experincing when using a rubber boot or other protective device. What
John does not say, and I would like to know, is why he is unable to
retune the antenna to compensate for the change in capacitance. Will
the antenna not resonate? or is there some physical limitation, such
as the radiating element being too short, ect.

73 Dloyd

Dloyd - The radiating element will be too short if it is cut, and there is a
problem with it resonating.