I just got an RSP1A myself a few days ago and set it up with CAT control. SatPC32 orchestrates the Doppler corrections and provides QSY data to HDSDR via a virtual COM port pair provided by com0com. The instructions in http://www.dk1tb.de/FAQ_e.htm#SDR_Radios%C2%A0are intended for interfacing HDSDR with SatPC32, but the instructions for the SatPC32 side of the interface should also be applicable to other SDR programs. That FAQ provides the info you'd need to set up CAT control of the VFO through SatPC32. The downlink receiver in SatPC32 needs to be defined as Radio 1, emulating the Kenwood TS-2000. You'll also need a means to set up virtual COM port pairs, e.g., using either com0com or VSP Manager by K5FR, as explained in that FAQ.

By faithfully following the instructions in that FAQ I referenced above, I've gotten this setup to work for CAT control of Doppler in several satellite passes. I'm using a Yaesu FT-857D for the uplink, and it appears to be reverse-tracking properly.

Unfortunately, in my limited testing so far, I've found the RSP1A to be substantially less sensitive than the KX3 or even the FT-857D in hearing satellite downlinks. Subjectively, I seem to be at least 2 S-units down in S/N compared to the KX3, maybe 1 S-unit down compared to the FT-857D. I can hear the CW beacon just above the noise, but not well enough to copy it, much less make out voices in SSB or FM. I also seem to be picking up a lot more intermod or other interference with the RSP1A:  earsplitting birdies within the passband that are not audible on the other radios when switching back and forth. So far, my reception on the RSP1A isn't nearly good enough to work stations that I could work if I used the KX3 or even the FT-857D for the downlink. May have to try the FT-818 next; unlike the KX3, it should be controllable by SatPC32, at least after I acquire another CAT cable to connect the radio.

I've only had the RSP1A since Friday, and it's my first SDR, so I still have a lot to learn about the features that can be exploited with the SDR software. I haven't tried SDRUno or any other SDR applications yet, and will keep playing around with filters and other settings to see if I can improve my reception.

Hope that helps.

73, Ryan AI6DO

On Monday, January 14, 2019, 3:11:24 PM PST, James Brown [email protected] wrote:

Just bought a sdr1.what setting to I need on Sat32 for downlink receiver?