On Thu, 04 Nov 2004 21:59:02 GMT, sideband wrote:

tnom:

Explain this, then... CB radio in my Peterbilt, with a mirror mounted
Hustler HQ-27 on the driver's side.. 6 feet of coax shows a 1:1 on 19,
1.1:1 on 1, and 1.1:1 on 40... 12 feet of coax shows the same
readings... 18 feet of coax shows.. guess what? the SAME RESULTS.

IT IS possible to get near "perfect world" results with a little work,
and attention to detail.

By the way, I've gotten similar results on two meters with a magnet
mount 5/8 2M Lakeview whip on my old Ford LTLA9000. Had to shorten the
coax because I was sick of the bundle of it in the cab... no change in
SWR over a four MHz bandwidth...

There goes the "magmount theory" as well..

If changing the length of the coax changes the SWR, then there is
something wrong with the antenna.

-SSB

SSB;
I know this was addressed to Tnom, hope you don't mind my 2-cents
worth.

Very few mag mounts have an adequate "RF" ground, at least on 11
meters or lower. There isn't enough capacitive coupling to the
vehicle body. In some cases the length of the coax can matter, not
from a matching point of view, but as a counterpoise for the antenna.
I have seen mag mount installations where you could see the SWR change
just by moving the coax around.