RF interference from RV50/LS300?? 900 mhz

I am experiencing a technical hurdle I cannot figure out. I am using a LS300 as a internet gateway for collecting data from 9 GPS geodetic stations. The stations use radio (900 mhz) telemetry to send data to the gateway. I get excellent radio shots with 100% ping returns UNTIL I plug in the LS300 to the master radio. At that point the connections get very intermittent. ~(1% ping returns) The LS300 is routed through a VPN. I can remotely access the LS300 and the local master radio. Everything points to some kind of RF interference but the radio antenna (yagi) is 4 meters from the modem. Any suggestions?