[amsat-bb] Question regarding gain of Dish Antennas with different feeds

[W1BFN@xxxxxxx]

I looked at the G3RUH Patch Feed last night and must have one!

Question: Will the Gain of the patch antenna increase the overall gain of the 
dish I put it in, either directly by virtue of its stated gain, or indirectly 
based upon better coverage of the dish surface? I understand that going 
circular will certainly help, and why.

It's probably too soon to make an intelligent decision about this, but given 
the S meter calibration of my receiver, I can copy SSB with difficulty down 
to about 3 dB above the noise level, and reasonably well at 10 dB above the 
noise. Given that I should hear no signal louder than 10 dB below the beacon 
in an ideal, Leila controlled world,  then I think I must be able to hear the 
MB at 13 to 20 dB above the noise. That level is approximately S7 to S9 on my 
receiver. Even with fairly favorable  squint angles (below 15 degrees), I can 
only maintain S7 out to 39,000 km, and that is where I can no longer use the 
transponder. Going circular with a good same-size dish won't help very much.

This begs the question: How much addition gain Might we expect from the S1 
dish when it is brought on-line? as much as 10 dB? that would be good, I 
think, but would it be good enough? Inquiring minds want to know.

Mike, W1BFN

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