Just some other data points as we have done quite a bit of testing in the
last year on ground planes.

Conductive paint ground plane with external com antenna  VSWR 1.15:1-1.3:1
at mid freq.

Copper mesh or aluminum tape ground plane on inside
VSWR 1.7:1-2.0:1 at mid freq.

No ground plane only using carbon
VSWR 1:8:1-2.4:1 at mid freq.

These were actual tests conducted on multiple airframes using a digital VSWR
meter.

This is for com.  We have had excellent results with com, nav, transponder,
and TCAD antennas using the conductive paint.  I have heard that the paint
can breakdown overtime.  I'm not sure how this can happen under a coat of
WLS primer, but I'm sure someone will educate me :)  So far we have a couple
of airplanes now that are 2+ years old with no appreciable degradation.

Regards,

Timothy Ong