R9DS Range Problem

Radiolink R9DS Range Problem.
Used on APM 2.6 board, with Radiolink AT9 and PRM-02 module.
The range was so poor, even in short range the R9DS would lose signal and triggered RSSI Alarm on AT9.
The other thing was, the telemetry data never showed up on AT9's screen.
This never happen before when I still use stock R9D. The range pretty OK and telemetry data showed on AT9' s screen normally.
Uploaded for evidence.
(sorry for poor censorship of my swearing)