Re: [amsat-bb] no patches for offset dishes!!

[Howie DeFelice <hdefelice@xxxxxxxxxxxxxx>]

......."If really needed, you can fix it with a small screw
directly at the center point to the ground reflector: as this point should
be somehow neutral due to symmetry, this might work, but to my knowledge
never been tested."........

I have tried this configuration and found that it changes the resonant
frequency of the patch from the ungrounded configuration predicted by the
patch16 program. I forget which way it moved, but it wasfar enough that the
SWR could not be tweaked by bending the patch. I used a 2-56 machine screw
as the ground post. After removing the ground post, I was able to get the
patch to work fine. I am using a 60cm prime focus center fed dish. I was
going to put the ground post back in, measure how far the resonant frequency
moved and try to re-scale the patch but never got around to it.

Regards,
Howie AB2S




----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org