Charles writes:

<<<<The only thing that a low VSWR guarantees is maximum power transfer from the source if its impedance is that of the VSWR measuring device. It absolutely does not guarantee radiation efficiency. >>>

True enough BUT a high VSWR will virtually guarantee poor performance relative to the same antenna with a low VSWR.

<<<<
Without doing antenna range type measurements, I am concerned with using carbon fiber as your ground plane.>>>

Yes, me too,  that is why you should install the 22" X . The point was (is) that to get most of the benefit you don't need a solid ground PLANE, just 4 wires spaced 90 degrees apart.   Builders have reported good and bad performance with just carbon but this fix is so easy, cheap, light and quick to install that there is no good reason NOT to do it.

It worked in the demo and it works in my plane and as I have said before, one test is worth a thousand expert opinions.

It may not be the absolute best solution but it gets you 98% of the way there with 10% of the effort. When was the last time THAT happened?

Regards
Brent Regan

For more on VSWR:  http://www.antennex.com/preview/vswr.htm