RadioBanter - View Single Post

July 10th 03, 06:42 PM

In article ,
says...
Motorola did a number of one chip FM TX ICs, - they are cheap and widely
available

that must be why i have a hard time finding the MC3361 or maybe it was
the 3362 used in RC aircraft receivers. Motorola sold the Mosaic line
and it's hell trying to find 'em. yeah, i know. they're receivers. but
it's still from the Mosaic line.

what suppliers do you suggest? i used some parts search engines and the
number in stock varies from day to day.

mike

and produce about 50mW output which can be use to drive something
like a 2N3866 output stage (I only give that device number as I have one in
the junk box!)

73 Marcus M3ChB

"R C" wrote in message
m...
Hi, I'm looking for a small, 2m FM fixed frequency TX design for a
backup telemetry link on a model craft. I've seen designs based on
discontinued Motorolla baby-monitor ICs, but simple varactor/tripler
designs seem less common. Weight/size are important, and I'd like
output around 1-2W. Duty cycle will be fairly low. There is 4.8V or
12V available already; 4.8V is likely to be noisier, as it drives the
servos. 12V is prefered.

What I was thinking was ~48 Mhz crystal oscillator with varactor, fed
into a tripler, then a bandpass, then into an amplifier (RF
transistor?)?

I've seen a number oscillator designs floating around (handbook and
otherwise), but I don't know how to find out what's most appropriate.
Any suggestions, designs I've missed, books to read, etc? Something
like the Ramsey FM6 (preraid)?

Plan B is to find another HTX-200 or similar, pull out the guts, and
use that. But I'd rather have something I can lay out myself.

Thanks,
R C
KG4MVB