"Bernard" wrote in message
news:5Wwie.9489$jj.5508@lakeread06...

1) It is homebrewed
2) There is room for a "powerful" microprocessor that will do other things
(APRS is one of them)

Nice goals, but your target market will be kind of limited. Whatever you
come up with is going to cost 2-4x commercial. I can't really see the point
of APRS. A nice, compact, inexpensive APRS box would be nice, but a
homebrew VHF rig isn't going to get there. Now, maybe a little box with a
TNC and GPS built in that would plug into an HT might come close, but that's
not what you are focusing on here.

2) RX band filters: I have decided to have a fixed capacitor and adjust
the
inductor.

That does make for harder parts selection. Why that choice?

5) 2nd mixer crystal. The 10.245 MHz crystals are easily available but not
the 21.4 +/- .455. This seems to remove the option of using a 21.4 MHz
IF..

10.7 is a pretty low first IF. You might consider using a higher IF and
winding the transformers on toroids.

8) PLL: I am currently leaning towards National (LMX2306 or similar).
They

Think about DDS. There are some really nice DDS choices from Analog Devices
and TI. TI has some really nice, cheap synthesizers. DDS is way less of a
pain than PLL. TI's 440 MHz part can easily work down to 2 meters. Yes,
they are pretty much all TSSOP but that is manageable to hand solder on a
PCB. Messy to prototype but then that will be a problem at VHF anyway.

...