Hi Michael,
I finished the prototype this morning, and it does work
pretty well on low to medium level signals. On very strong signals, there is
a little bit of edginess on the modulation peaks.
As far as the NE602, you can feed the limited I.F. signal into pin 6, and
this works out pretty well.
My next iteration of this circuit will be one that uses a Philips SA637.

Pete

Michael Black wrote in message
om...
"Pete KE9OA" wrote in message
...
I know...........it seems that the more you learn, the more you realize
how
much you just don't know.
On another note..................I am working on a quasi-sync detector,
so I
should be able to build the prototype unit up this Monday. Basically, it
consists of a limiting amplifier (MC1350) feeding the squared up I.F.
signal
into the LO input of an NE602. The unconditioned I.F. signal it fed both
to
the input of the limiting amplifier and to the RF input of the NE602. It
should be interesting.
I've been meaning to get around to these things for the past couple of
years..........I'm glad that this radio project came along.

Pete

Do you actually need two ICs? The MC1496 datasheet talks of using
it as a "synchronous detector" but even mentions that an external
limiter is not needed so long as the signal level is sufficient.
I don't suppose that can work out with the 602?

For that matter, the variable gain stage in the MC1350 is
a "Gilbert cell" and it can be used as a mixer, albeit one
with a gain stage between it and the output pins. Could it
be better suited for a self-limiting "synchronous detector"?

I don't suppose the MC1330 which is the same scheme intended
for detector use in TV sets, is still available and suitable?

Michael