Certainly that's true. But I would say "for a given size" is a quite valid means of comparison. How many of us are truly unencumbered on antenna size? It all boils down to what you can squeeze out of your "given size".
At 21:25 2006-09-09, Gary "Joe" Mayfield wrote:
At some point (not that high in frequency) the beamwidths get so narrow the antennas are hard to point. Both on the satellite and on the ground. I don't think a spot beam would be popular with those living outside the spot. *for a given size* is a biased measurement.
73, Joe
----- Original Message ----- From: "Scott Townley" nx7u@arrl.net To: "Amsat BB" amsat-bb@amsat.org Sent: Saturday, September 09, 2006 2:04 PM Subject: [amsat-bb] Re: Eagle efficiencies
Clarification, or more fuel to the fire... For a *fixed overall physical size (aperture)*, antenna gain is proportional to f^2 Pathloss is proportional to 1/f^2 So then the total link budget actually *increases* with increasing frequency (f^2*f^2/f^2=f^2), since you have an antenna at both ends, subject to the assumption stated initially. There are several 2nd-order terms to consider overall, such as decreasing transmitter power as frequency increases, thermal/galactic noise variations with freq, etc., but *for a given size* higher is better.
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