It's all about the Software

Ah yes - SDRC tuning is fixed. I think you said this works sometimes so having a sign inverted on a number entered into SDRC's setup won't be a problem. (And I am thinking out loud here.) Last I knew SDRC will not speak with a ProII directly or through a serial port adapter. So you must have somethi...

FWIW, srtb.msn.com seems to be a front door for Microsoft's Azure services.

{^_^}

That PSU sounds like it needs a careful strip down and rebuild or else a full disposal.
{O_O}

There is a chance that computer "horsepower" may be a limiting factor depending on how the other DSP apps involved are written. SDRC is pretty good by itself with up to and including 24 receivers. Keeping everything straight might become daunting, though.
{o.o}

Picture(s) of SDRC when working and, if it can be done, when stopped that show settings would help. That collection of parts all presumably interconnected seems to suggest to me there are likely loops in the control paths that invite problems. A simple sketch (labeled rectangles will do) of how you ...

I hope so, too. I prodded Simon on this. I was thinking of the ribbon menu settings, The one visible to the right, next to the one you showed dropped down, is a gain setting. It seems he may have renamed something. Making those all the same MIGHT have an effect. Also check that the if filters are se...

I note that you have different settings for the FFT. Your line rates and other settings (lower right of waterfall area) show the different settings. Fiddle with them to get them the same if possible and see what happens. It looks like with 3.3 you've picked up some problems. Let's try to make all th...

(Error analysis widget stuck in my head keyed in. I can't help it.) How accurate are you trying to get. In the world of the physics class SDR implementation with (near) infinite precision and resolution and one single oscillator in the front end you should be precisely on target if you pick a freque...

For calibration of what? For front end frequency calibration is this better than setting DSB on WWV and listening for the zero beat? And that is not a very good calibration; but, better than any other HF stations. For VHF and above your best calibration depends on the country you are in. This is usu...

Maybe open a new bug report for that last item. But, it might be a race condition among the various processes all talking to each other here. But, it might be within SDRC. And only Simon can add logging for this issue. Some radios are insanely sensitive to receiving too many commands too quickly. So...