I have no experience in building one either, but I would think that the 10.7 MHz IF of a typical FM receiver, designed to feed a 455 KHz 2nd IF, would give ample bandwidth. Follow it with a 100KHz filter, mix with a 14.2xxx LO, into your 24 MHz PA, and you've got a transponder.
I think... George, KA3HSW ----- Original Message ----- From: "David Giles" <[email protected]> To: <[email protected]>; "amsat...@amsat. Org" <[email protected]> Sent: Saturday, June 06, 2009 5:50 PM Subject: [amsat-bb] Re: HF satellite? > Hello Bob and others, > > Just to get the ball rolling on what you require for the 10m/12m > transponder. I have no experience in building anything like this, just > a lot of questions buzzing around. > > What are the maximum physical sizes? > What is the power supply voltage and maximum current? > Does it need a beacon, be it a keyed input or even a continuous carrier? > Can it use any sections of the #2 transponder? e.g. an IF output from > the 29MHz section. Or will they just share an antenna? > How much bandwidth should it be? Can it be based on a ceramic filter > e.g. 50kHz at 4.5MHz from a TV or 25kHz at 45MHz used in FM radios. > What is the expected 12m power output? > Are there any link budget calculations? > Is there any segment of the 12m band that will be better suited? In VK > SSB is recommended from 24.930-24.990MHz > > 73 de David VK5DG > _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
