In article , says...
Dale Parfitt writes:

wrote:

I'm looking for a 70cm receiver schematics. Nothing fancy just
something simple that works.

Thanks.

Does mode matter?


Regular FM voice I guess for listening into 70cm repeaters/simplex freqs.

If there's not a whole lot of 70cm activity near you, you can build a
simple single-conversion NBFM receiver with any of several chips from
this product line
(http://www.semiconductors.philips.co...r/SA604AD.html
) in an afternoon. Just leave the front end untuned. You won't have
any image rejection with a 455 kHz IF, but chances are better than good
that you won't have any images to reject on that band.

DigiKey sells ceramic filters (TK2332-ND is a good choice for NBFM as
well as AM applications) and slug-tuned discriminator coils for 455 kHz
(e.g., TK2502-ND) for use with the Philips chips.

A Mini-Circuits POS-500W VCO (200-500 MHz, -100 dBc/Hz phase noise, +10
dBm out) would give you coverage of both 220 and 440 MHz. Tune it with
a 10-turn or 20-turn precision pot and a well-filtered power supply.
Not the greatest stability, but it'd work. It also wouldn't be too hard
to add a digital frequency display with a microcontroller (to subtract
the 455 kHz IF) and prescaler....

-- jm

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