"J. Reed" ) writes:
The most practical FM detector, for both fidelity and cost would be a
phase-locked-loop chip...

Well there was an article in QST by Bob Heil about converting a CB set
to FM, I'm pretty sure it was in 1981.

As I said here back in 1998:
Converting a CB set to FM, once the conversion to the appropriate
section of the 10M band has been accomplished, would consist of FM'ing
the transmitter (I can't remember, but I assume the articles disable the
AM modulation of the final amplifier, and feed some of the audio to
the VCO), and adding an FM detector to the receiver. The two articles
I can remember used IC detectors, which would add some IF
amplification and limiting before the detector. One thing worth
considering is that you can easily scrounge up a 455KHz FM IF strip from
a cordless phone, or a 49MHz superhet walkie talkie.

I wouldn't say fidelity is an issue here, given that it's narrow deviation
we are talking about and that's not a problem to get a linear discrimator.
YOu probably will get a better results with a full FM IF strip, and those
are really easy to pull from various things, either just the IC (any old
TV set will have one for the sound demodulator, at least in North America),
or for that matter any FM "stereo receiver", or as a full IF strip. The
advantage of the latter is that the discrimator is already aligned, and
you get not only the demodulator IC but the needed IF transformers and
FM-bandwidth filter(s).

You can find such strips in cordless phones (I found some a few weeks ago
that were for 2.4GHz, and they still had defineable IF strips with 10.7MHz
and then 455KHz conversions), or those 49MHz walkie talkies, or older
cellphones (which have the advantage of being cheap and don't have high
integration in the ICs). I've never found a scanner in the garbage, but they
too would have such IF strips. Even commercial 2-way equipment had such
IF strips, and even recent ones may (though since I'm not familiar with
recent equipment I don't know if they are still going down to 455KHz.)

Michael VE2BVW


wrote in message
oups.com...
Hi All,

Anyone recall or have a copy of the articles in Ham Radio, QST, or 73's
which has the 455KHz FM detector and the other information for Cb
conversion to 10m FM?

I recall that Melco did some kits, I recall the article but can not
locate it in my library.

I believe I saw a FM demodulator either HR or HR Horzion.

thanks de KJ4UO.