Hello,
I sent off my observations months ago to the DSDplus and got a response back that there are no problems. I was able to test the different RSP models. I think the DSDplus development team wrote FMPP to support the RSP2 and just left it. It seems FMPP is only updated to the latest API without really considering the other API changes. FMPP seems to only know about the RSP2 gain settings.
There is no squelch logic control (-q) and scanner mode (-s) does not seem to work.
No bias tee support for the RSPduo, RSP1A, and RSPdx.
On the RSP1A, the Antenna Select and Notch Filters controls seems to disconnect the antenna. I get a spectrum with no signals.
On the RSPduo, both antenna inputs are active. The Antenna Select and Notch Filters cause a freeze and restart of the input stream.
On the RSPdx, both antenna inputs are active with Antenna A being more sensitive. The notch filters seems to work. The Antenna Select seems to disconnect the antenna. I get a spectrum with no signals.
73 Eric