[Motorola] Motorola Transceivers As Linear Amplifiers

[N0KQY]

"WB6BLV (DM06)" wrote:
> 
>   Has anybody here ever changed the
> bias and drive on solid state Moto power amp boards and successfully used
> one as an SSB linear?  

      

 Any information on how to go
> from Class C to linear with such power amp boards will be greatly
> appreciated!
> 
> John,  WB6BLV at inreach.com



John,

Yes, I have changed several of the Motorola PA boards over to class AB.
Low band, Hi band, and UHF Mitreks. Removed the RX/TX circuit board and
used the chassis for a transverter housing. You will find excellent info
on doing this on G3SEK's web pages under transistor bias circuits.


http://www.ifwtech.co.uk/g3sek/ 


However, this project is not an easy one without the proper test
equipment and a very good understanding of transistor principals.
Motorola's transistors are characterized for class C and not all of the
PA boards are good choices. One out of three power amps ended up in the
junk pile because they would not meet IMD requirements with a 2-tone
test. Each and every board that I have re-classed to AB did not use
identical values so there is no easy schematic to follow. 

Gary

N0KQY