"Mike" wrote in message
m...
I have a couple of GP-9s and can tell you the gain figures are a bit
inflated and not referenced to anything. A dipole array with optimum
spacing between dipoles is about the most gain for size that I have
encountered in VHF/UHF antennas. For VHF, a four bay dipole array at 20ft
in length has 6dBD gain omni and the GP-9 claims 8.5dB(?) from three 5/8
elements. On UHF, a 16 element dipole array has about 9.8dBD gain and the
GP-9 claims 11.9dB(?) for eight 5/8 elements. Something looks fishy to me.
Mike


Nothing can distpute your math - something's up.

I've changed plans a bit, though - the Boeing ARC 2 meter
repeater is only 4,000 feet away and I'm worried about
intermod. So, instead of a high gain antenna at 20', I'm going
to go with a moderate gain antenna 10' higher. The idea is
to get good gain with a farther horizon rather than high gain
with a closer horizon.

Plus, it's cheaper, too!

Instead of the GP-9 @ 20', I'm going to add a 10' mast
and go with a GP-3. Installation sould be a lot easier, too.
Now, though, my gain figures are 2.913 db improvement
on VHF and 3.056 db improvement on UHF.

I'm seriously starting to wonder if I should just leave well
enough alone - the MFJ-1729 is performing well. I was
talking to N0IDW on the 145.19 Winfield, KS machine
(a distance of 32 miles) and I could hit the reverse button
and hear him on the input. He, however, could not hear me
on the input.


Ken KG0WX