VHF Antenna

I need a better antenna for the handheld radio in our homebuilt. Fisher
Horizon 2 wood and fabric construction. I thought I had found a
construction article for one that could be mounted internally in the
fuselage behind the pilots seat. It may of been Jim Weirs' design but I
can't find it. As I recall it used copper tape and some aluminum plates.
The biggest problem I have is getting a big enough ground plane. I think
this was all built into one unit that I could mount vertically to the inside
of the fuselage. Something like the one that Advanced Aircraft sells.
Anyone built anything like this or something similar.
Thanks,
Dave
N203ED