Jay in the Mojave wrote:
Hello Jim:

Yeah 18 feet seems top work well in a mobile installation. Why is that?

Is it because the antenna puts RF Energy on the coax outer shield due to
a lack of ground surface. In all my antennas installs it seems that way.

So 18 feet of coax is roughly 3/4 of a wavelength, ( with a velocity
factory of .66) and any RF Energy coming back will have to come back
thru another 3/4 wavelength of coax.

Maybe that length vs wavelength is the best to use. Your comments....

Jay in the Mojave


jim wrote:
Feed length 'does' make a difference

when calculating swr

Hey Jay, I was taking the **** when I posted that. We've seen many posts
on this subject in the past and was fishing for someone to start an on
topic post. It was an SWR vs feed length thing. I don't believe so with
the limited length in a mobile installation (though you quote 18' which
is particularly long IMHO). In your opinion why does it matter?
Regards, Jim.