"KE5MBX" wrote in message
ups.com...
On Feb 2, 9:35 pm, "Stefan Wolfe" wrote:
"KE5MBX" wrote in message

oups.com...

I have been advised by some hams that the best way I can hope to do 10-
meters on my jeep is to mount my antenna ON THE WINDSHIELD to get a
good ground plane. I read somewhere since then that the primary
reason for cophasing CB antennas on trucks is NOT to direct the gain
front and back, but to even the ground plane as though the antenna
were in the center of the truck. Could I achieve the same effect with
my Jeep by cophasing antennas on either side of the jeep by the
doors? Even better- could I do this diagonally across from one corner
of my jeep to the other? I heard the further apart the antennas are,
the better, and I'm not really trying to get front/back gain for DXing.

What I did was purchase a 1/2 wave 11 meter whip from Radio shack and
trimmed it for 10m. Of course, for 1/2 wave you need not have a ground
plane, only a good ground point. I mounted it on the back bumper. It
worked
very well on my Warngler.

Wow, that is some excellent information I didn't know.. that a 1/2
wave antenna doesn't need a ground plane. I looked it up and sure
enough, you're right! However, I'm sad to say that I really doubt
Radio Shack sells a 1/2 wavelength antenna for either 10 or 11
meters. The classic 102" whip, as I understand, is a 1/4 wavelength.
For a second I even considered putting a 2.5-meter (16.4 ft) whip on
my jeep, but I finally decided that really isn't practical. So, any
opinions on the cophasing of two 1/4 waves?

You are right of course...sorry...I didn't caculate the wavelength and was
merely making statements comparing the shorter "loaded" whip (forgetting it
was loaded), concluding the longer whip was 1/2 wave . However, I knew it
was 1/4 wave GP at the time and sometimes I just get afflicted with
oldtimers didease, complicated to exposure of high EM fields. :-)) The
unloaded 1/4 whip still worked well using the frame as a ground plane.