[amsat-bb] Re: HF satellite?

George Henry ka3hsw at att.net
Sun Jun 7 10:35:28 PDT 2009

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" <vk5dg at amsat.org>
To: <bruninga at usna.edu>; "Amsat-Bb at Amsat. Org" <amsat-bb at amsat.org>
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

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