Re: Question about vacuum and power module for linear transponder
In a message dated 19/12/2009 15:36:41 GMT Standard Time, pe1rah@yahoo.com writes:
I also would like to know if anyone has experience in SSB mode with the new power modules types from Mitsubishi. Like the RA60H1317M, which can give 60W power on 2m with only 50mW input power. I am looking for some PA behind my LE005-R2 transponder design, to get a small sized high-power linear transponder. The transponder gives 200mW PEP, so the 50mW is no problem at all.I just wonder how linear these Mitsubishi modules are, when using in linear mode.
Hi William.
The RA60H1317M is hopelessly inefficient for use in space. It has reliability issues linked with the junction wires where they bond onto the substrate. 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%
Besides....where is your 60W going? Venus? Huge power....
David
----- 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
participants (2)
-
G0MRF@aol.com
-
i8cvs