All packets corrupted when using SIK radio


I have a PXFmini running ArduPlane, and when configuring it to transmit telemetry using a SIK radio (using sudo ./ArduPlane.elf -A /dev/ttyUSB0) all packets appear corrupted on the receiving end. When I use a UDP link over wi-fi to transmit telemetry, the system appears to work fine, and MAVproxy and APM Planner receive valid telemetry data.

When using the SIK radio, MAVproxy shows a lot of noise: and no valid packets. My SIK radio parameters are here:

Additionally, testing using a serial terminal program seems to work, packets sent to one radio appear on the terminal screen for the other radio, and vice versa.

How can I get the SIK radio transmissions to work?