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Old January 24th 08, 01:50 PM posted to rec.radio.amateur.homebrew
Tim Shoppa Tim Shoppa is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 263
Default Good reading on radio modifications/building

On Jan 23, 11:10*pm, wrote:
I'm curious about how I might modify say my Aviation Radio (my hand
held spare I keep in case of lost electric in an aircraft). To pick up
amateur bands as well as the Aviation bands.

I'm not interested in the slightest as to whether or not this is
legal, I'm simply looking for educational purposes.
I wanted to get one and then I became curious ... as to how difficult
it would be or how it would be done, what kind of reading I would do
if I wanted to build/modify any radio etc.


Aviation radios are 117-138 MHz AM modulation. You can either cut some
diodes in the PLL to move them to 2M (144 MHz) or put in new crystals
to move them to 2M. But... there isn't much AM activity on 2M (no
insult intended for the AM diehards, I appreciate their efforts) it's
almost all FM and you won't be happy. AM demodulators kinda sorta will
demodulate some FM signals legibly but you won't have the fine-tuning
controls you'd need to do a good job.

All the HF bands will use predominately CW or SSB or other digital
modes that are not demodulated well by an AM receiver. While there is
some AM activity there too, your aviation receiver's front end would
never let you receive on the HF bands.

Tim N3QE