Provide us with a few more details.
#0. Receive? The Shari receiving or your HT? (by that- the shari is transmitting you (HT) are receiving.*
#1. any new light bulbs or appliances nearby. In your home.
#2. home or apartment? if apartment how many feet to the next neighbor...
#3. Have you tried:
???? a. another power supply?
???? b. another branch circuit in your home...
???? c. Another HT or mobile rig.
*? If you go into the Simple USB Setup by SSHing into the RPI, you can force the Shari to transmit with no data streaming, which would give you what they call a dead carrier..?
My experience with SHARI's and I've had 6 through my hands, built and set up a number for Blind hams. They are excellent in design (albeit the money) extremely well documented and extremely reliable. I have some running 3-4 years without a single problem.
Merry Christmas,
Larry W8LM
Mulvane, Kansas
Larry Macionski