"karel adams" wrote in message
...
I want an airband receiver in my car (well, a van actually)
and wonder what antenna to use best.
just the normal car antenna perhaps?
i even wondered about jim weir's J-antenna
but am afraid the van's body will be too big a grond plane

TIA,
Karel Adams

As someone else pointed out, you can't have too much groundplane.
J-antennas are relatively insensitive to groundplane or lack thereof,
because they're half wave.
The "glider retrieve" crowd tends to like a 5/8 wave whip, which requires a
ground plane and an impedance match, have a narrower bandwidth, and are
taller so they run into more overhanging objects, but puts more of the
signal close to the horizon, so the range is better, ground to ground. (This
is a _retrieve_, remember).
If you can put one of Jim's antennas on your van so that it doesn't whack
too many overhanging things, it should work fine.
I have seen J-poles mounted on bumper hitches and van rear-door hinges, to
keep them a little lower. I doubt if the antenna pattern was precisely
omnidirectional, but the people using them thought they were "good enough".
A quarter-wave whip should also work, and might whack fewer things.

Jim might even agree with this: like airplanes, antenna design is about
compromises.

Tim Ward