----- Original Message ----- From: G0MRF@aol.com To: pe1rah@yahoo.com; amsat-bb@amsat.org Sent: Saturday, December 19, 2009 9:01 PM Subject: [amsat-bb] Re: Question about vacuum and power module for lineartransponder
Hi William.
A better solution would be to build a class AB linear from 2 suitable FETs. An even better solution but one requiring a lot of development would be to separate the modulation into phase and amplitude and then modulate the gate with phase and drain with amplitude. Efficiency >80%
David
Hi David, G0MRF
What you suggest is the HELAPS principle of Envelope Elimination and Restoration that was used in all linear transponders from OSCAR-6 ,OSCAR-7 OSCAR-10 and OSCAR-13 with an efficiency of about 85 %
http://www.amsat-dl.org/dl/HELAPS_en.pdf
The above is a complete description of the HELAPS principle written by Dr. Karl Meinzer DJ4ZC with all functional schematic diagrams of the linear transponder Mode-B on board of OSCAR-7
I hope it helps William PE1RAH
73" de
i8CVS Domenico