[amsat-bb] LVB tracker noise

I am using and LVB tracker to control my GS5400B AZ/EL system. I mainly use it on EME and WSJT controlling it with NOVA. There has always been excessive noise shown on the waterfall when I am on certain 144mhz frequencies. I can cut power to the 5400 and it goes away so I am pretty sure it is either the box itself or the USB connection. I have put toroids on the cable ends. I have also tried different computers and it is the same. Any ideas on what I could do to remedy this. I can cut power to the rotor and all is fine. But the I have to restart NOVA each time. I could live with it if I could just switch the Rotor control off and on without restarted NOVA etc..

Thanks Joe KI4TZ