RadioBanter - View Single Post

July 10th 03, 06:53 PM

In article , says...
Can anyone provide some part #'s for these one chip FM TX & RX IC's? I'm
interested too.

MC2831A, MC2833, MC13175, MC13176. i got samples of one of 'em a long
time ago, but as i said in another post, motorola sold the Mosaic line
to either Micro-Semi or On Semi. either way, it's hard to pick a chip
for an app without the data sheet. before you ask me to scan and e-mail
them to you, tell me how to get my HP scanjet 3c to run on w2k and XP.
HP doesn't even know how to make work on win9x. the website has software
for 9x, but they fail to mention that you have to install DOS software
first. That doesn't work with NT systems like 2k/XP.

mike c

Marcus Sleightholm wrote:
Motorola did a number of one chip FM TX ICs, - they are cheap and widely
available 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