The regular car antenna should do fine and save you a bunch of hassel.
I'm not familiar with the anetnna design you're referring too but
there is no such thing as "too big" for a ground plane. You're
approximating infinity (relative to the wavelength of the carrier)
with whatever you use, its just an issue of diminishing returns by
making the ground plane overly large. You're going to have to find an
adapter between the car antenna plug and the BNC or whatever your VHF
comm radio uses. But a linear on that sucker and make friends
everywhe "Breaker breaker, a big 10-4!, I'm at zero-zero AGL and
making 25kts in a school zone."

Regards



"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