PCR100 IF out -> HF receiver for SSB/CW?

[jonny290]

Any reason why this wouldn't work to receive SSB/CW and to use the superior filters of the Icom 735?

10.7 MHz IF out of PCR100 -> IC-735 tuned to 10.7 MHz

In theory I could tune the PCR entirely via computer and have the HF receiver demodulate CW/SSB.

Already have all the gear, it'd just take a quick mod to pull IF2 out of the PCR100, then a connecting cable and maybe an attenuator or something.

 

[steve_s]

Any reason why this wouldn't work to receive SSB/CW and to use the superior filters of the Icom 735?

10.7 MHz IF out of PCR100 -> IC-735 tuned to 10.7 MHz

In theory I could tune the PCR entirely via computer and have the HF receiver demodulate CW/SSB.

Already have all the gear, it'd just take a quick mod to pull IF2 out of the PCR100, then a connecting cable and maybe an attenuator or something.

I would think it should basically work. However, there will be three hurdles to overcome:
1. You will need a buffer / impedance matching device to convert the high impedance out of the PCR's mixer to the 50 Ohm imput impedance of the IC-735. This buffer should have a resistive input, so it does not introduce stray reactances iback into the mixer (the same applies when connecting a SDU).
2. You would still want to have computer control of the IC-735 (or manually fine-tune it), because the step size of the PCR100 is too large to tune a SSB signal.
3. I don't know off hand what the stability of the PCR100 synthesizer is, but I could imagine that you might have to re-tune the IC-735 quite frequently to compensate for the drifting synthesizer. Of course, locking the PCR100 reference oscillator to a lab standard would solve that problem.
It sure would be a nice setup.

 

[jonny290]

I don't need 100% computer control, I'm happy with 'fine tuning' the signals in the 735. As far as I can tell there should be sufficient passband for fine tuning via 735.

There is a reference oscillator but it's not temperature controlled. I may build a crystal oven for giggles if I need it.

Going to design the buffer amp /attenuator this week (am guessing I'll need to throw quite a bit of attenuation into the circuit at times).

 

[steve_s]

Going to design the buffer amp /attenuator this week (am guessing I'll need to throw quite a bit of attenuation into the circuit at times).

Yes, I would think so, too. Instead of a buffer you might even be able to use a VERY small series capacitor (maybe 1 pF or so) between the mixer and the IC-735 antenna. This might just give enough isolation and attenuation.
If you can tune the IC-735 from 5 to 20 MHz and not see ANY dip in the PCR's signal strength (as seen on the PCR's S-meter), especially as you tune the 735 through 10.7 MHz, you should be all right.