Removing Radio Frequency Interference (RFI) can be quite a challenging issue, but it can be solved. There's a number of things that should be done to minimize the effect of this noise. A basis for this can be found from the American Radio Relay League (ARRL), but some of it is just from experience.
- All of your sensitive equipment should be in a Faraday cage, or at least a metal box.
- Try to use a simple radio scanner to find the source of your frequency. Those items should also be in a metal box or Faraday cage.
- Isolate power lines using high end filtering devices.
- Use proper grounding and keep wire lengths short.
- Keep anything in the radio pathway clean, with solid connections.
- Pay attention to where your antennas are pointed when you see the RFI issues, what time of day, etc. This can be useful information in pinpointing the exact location, which makes the problem easier to solve.
Bottom line is that you have to find out where the RFI is coming from, and fix it. In most cases, it is technically illegal to produce RF without a license, so vendors, neighbors, and power companies should be willing to help you remove it if you can track down what device is causing the issues. Good luck!