Simple DC Power Cord Noise Filter Choke with Power Pole Plugs
The simplest, most cost effective DC power cord noise filter is a ferrite ring installed as shown in the picture (at the radio/device DC input) to stop DC feedback radiation back into the DC power line or into the radio/appliance to suppress common mode power line noise current on the DC power cord or to suppress common mode noise present on the power lines from degrading the performance of the attached device.
These chokes are cheap, easy solution for RFI issues. Just replace your existing power cord with these prewound cables and enjoy interference free operation.
Also make sure you connect a good RF ground to the transceiver ground post.
Note to Flex Radio users: Use snap on ferrites for firewire cable, speaker cable and mic cable, Ring ferrites for Antenna output and DC power.
For additional RFI suppression, use a feed line choke at the antenna to suppress common current on the coax feed line – see our store for feed line choke alternatives for use at the antenna.
If you use a linear amplifier we have RFI kits for linear amplifiers that help suppress RFI in your shack or in your neighbor’s house.