Complete module WORKING RF PA Output removed from an FM828 - classic OLD communications equipment.
Get yourself a low level exciter or sig gen source signal in the intended VHF frequency range, pump it into this PA Module (within the design frequency range) and you have 25W RF output into 50 Ohm.
Perfect to repurpose for that nice little FM transmitter (or single channel/repeater transceiver) project on 2 metres.
Many many forums, discussion groups talk about using these highly reliable FM828's on Amateur Radio 2m bands
I have some other FM828 series components, boards etc HERE - time to do some experimentation with this nice old analog communications technology!
PHILIPS - RF PA Output Module
Type: FM828 A Band (Mk2)
146Mhz ~ 175Mhz design frequency range
Dimensions: 179mm length x 50mm height x 79mm deep
Complete PA Board, mounting on the generous diecast heatsink which allows full output in environments up to 60C
Antenna mismatch protection circuits are not required or needed with this design
BNC input/output female socket
TX/RX relay switching incorporated on the PCB
All signals, power and control signals accessible via the side mounted feed-through pins
TESTING:
Checked prior to removing from a working transceiver which had other issues making it a "organ donor" for other purposes.
I had one suitable crystal for the A band exciter and sent the exciter RF off to this module (dummy load on the PA output) and had a nice solid 25W RF on 173.525Mhz at the output.
PA Module can use 10.8 to 13.8V DC supply
TX/RX relay (98927) is designed to be switched with 9.7V
PA input requires 30mW (50 Ohm) from the supplied exciter or signal generator source
Runs three Class C stages, finally ending up with 25W RF output into 50 Ohms
RF power transistors used BLY89A, BLY87A
Plenty of online schematics etc for this equipment (FM828)
SPECIAL NOTE: The topside "lid" of the diecast case is not showing, it went M.I.A !!! Now this may or may not be a problem. If you are using this module within a shielded enclosure (project transceiver for example) then no problems but if the new owner intends to fit this onto an existing FM828 you will need to have that lid already.
To make sure everything is kept clear of airborne dust, this module is now sealed in plastic.
