I have my RigPi working just fine for SSB HF operation using the RigPi Audio Board 3.5 jacks with homemade cables. The problem I'm having is with WSJT-X in FT8 mode. When I compare decoded signals from the RigPi setup to those I get on my ham shack computer running WSJT-X, I see 0-2 messages per cycle on RigPi but 1 to 2 dozen on the ham shack computer. Also, the contacts decoded on RigPi are almost exclusively CQ messages, which could be an important clue. The waterfall display shows lots of signals on both the RigPi and ham shack computer setups. In fact they look very similar. The RigPi radio control function from WSJT-X using Hamlib seems to work fine.

Here is what I have tried on my own so far.

Made sure the "CQ only" box in WSJT-X not checked
Made sure that Mumble was not running on RigPi.
Made sure RSS browser was shut down on RigPi desktop once the radio was successfully connected
Checked the clock timing. (compared displayed dt for CQ-ing stations on both setups)
Checked incoming RX audio level and tried lowering and raising.
Checked and compared the WSJT-X settings on both setups. 
Made sure AGC, Noise Blanker, Notch filter etc turned off on HF radio
Checked LSB selected and wide SSB filter selected on HF radio.
Tried interchanging HF radios and cables (to confirm problem is within the RigPi)
Set the Alsamixer settings per the Manual. 

Despite the limited decoding. I have completed a couple of FT8 contacts using the RigPi setup, so Tx Audio is passing through to the radio.

From what I've read, there could be a problem with the audio sampling rate not set to 48 KHz, 16 bits, but I don't know how to check or set this on RigPi. Also, I've read about resource constraints causing poor decoding, but the indicator at the top right of the RigPi desktop never show more than 20%.

Any help would be greatly appreciated.

Dave VE3RTL