crossband linear ssb transponder project

[KC4UMO]

I am looking for any information on linear ssb transponders.
The types that are used on the "Oscar" satellites.
I prefer a analog type. Not computer driven.

This is for educational purpose. To learn how they work.
What we are looking into doing is building a transponder that receives UHF ssb and transmits VHF ssb. 50 to 100 khz wide.

After this is built we have a guy that will fly it over several counties in his hot air balloon.

I have already started to experiment with a single channel transponder.

If anyone hears of or see's articles of interest please post.