[NLRS] Parts is parts

[Dan Larson]

Hello everyone.


I have recently come into possession of some cast away 2-way radio 
gear with some interesting parts, and I would like to ask the group
what I might be able to do with them.

The radios are E.F. Johnson Model #242-8615 800Mhz 2-way FM rigs. They were
apparently used with radio modems for digital purposes, since no microphones
came with them. They did have serial cables hanging out and were attached
to DataRadio modems. The speaker in the unit tells me it was capable of
2-way audio.

Inside the final PA transistor is an MRF847 45W out with 16W in. The 
PA transistor is driven by a MHW820-1 802-870MHz module spec'd at 
250mW in with 20W out.

I doubt that the module would be useful since 902-928 is way outside 
of its spec'd frequency range. But, perhaps at lower power might I get
anything at all out of them?.......

The MRF847 sounds like it could be put to good use in a 12V 900MHz amp.

Does anyone know if the radio itself could be modified for 900MHz by
replacing the driver module with one capable of 900-928 MHz? Of course,
that requires that the CPU / PLL and receive front ends could also be
made to operate at the higher frequencies. I *am* capable of building 
my own CPU to drive the MC145159 PLL IC. I have experience with AVR
and PIC microcontrollers.

Just wanted to know what anyone might be able to tell me about this
radio and / or its parts. Even if I can't make anything for 900MHz
out of it, those PA transistors might still make good final amps
for 432MHz or 222MHz. I've got a stash of MRF517's I could use to
drive them with. But what good is an amp with no radio to amplify?
I have not built a 900MHz transverter yet.

Dan KC0LUY