Do BlackGold's drivers require an exact frequency or base frequency?

For example, from Belmont Mux D is on CH57 which is 762MHz. However there is an adjacent analogue signal on CH56 so Mux D is offset by +167KHz, making the actual frequency of Mux D to be 762.167MHz.

There are two ways to handle this:
1) Scan every frequency including offsets (i.e. tell the card to check them all)
2) Scan just base frequencies and let the card find offset if required

There are additionally problems when tuning:
1) Some cards drivers will only accept base frequencies, so if you specify an exact one it will be ignored.
2) Some cards drivers will need to be given the exact frequency.

What it sounds like is happening in your case is (in my example):
1) You scan for channels, using the BlackGold card, and it finds Mux D on 762.167MHz - fine
2) When the Nova-t USB2 tries to tune into it it finds 762.167MHz as invalid - it wants 762MHz

Or it could be this:
1) You scan for channels, using the Nova-t USB2 card, and it finds Mux D on 762MHz since the driver will automatically go to 762.167MHz
2) The BlackGold card tries to tune to 762MHz and finds nothing since it can't find offsets in the driver

I know that the above reply is a bit waffly but I hope you understand it.