This RFI kit is specifically designed to suppress interference triggered by today's smart appliances used in the kitchen and household that act as "transmitters" and affect other appliances or radio/TV/Cable audio systems OR these appliances may act as "receiver" of energy from other devices such as ham radio, CB, AM broadcast and other electronic devices in the home. The problem is generally the AC power cable acting as an "antenna" picking up or transmitting signals.
The RFI kit has ferrite filters are selected to eliminate RFI from 1 to 300 MHz and are typically used on the AC power lie of your Washer, Dryer, Microwave, Refrigerator and AC powered Clocks and Lamps. The filters are easy to install, don’t require modification of the protected equipment and work in almost all cases.
What is included in the kit?
The RFI kit contains 3 ring filters (1.4" ID), 1 large snap on (1" ID) and 2 smaller (1/2" ID) snap on filters for clock or lamps. Installation examples are shown in the included manual. Simple, easy to install and effective in almost all conditions.
AM broadcast transmits on a low frequency with large antennas. Consequently it takes a large antenna to receive the signals. Typical “antennas” are AC house wiring, phone lines, long satellite or cable TV cables, DSL/CAT5 lines running between rooms, etc. The device wires that connect to these “antennas” need to be choked with as many turns through the ferrite as possible. Some installation examples are shown below on this page.
For AC/ DC power cords and coax cables the F240-77 (2.4″ OD, 1.4″ ID) “Donut” toroid is the most popular. Also available are smaller toroid donuts and Mix 77 beads. Shown below is a graph with 8, 10, and 12 turns through the toroid – obviously more turns has higher choking impedance. Mix 77 toroid products are HERE and Mix 77 small beads (for small wires) are HERE
F240-77 Turns Comparison from .1 – 8.1 Mhz
Shown below is a graph of frequency response verses choking magnitude for a F240-77 in the AM Broadcast band for a 12 turn coil around the toroid. (Same info as above but different frequency range).
F240-77 Choking Impedance in AM Broadcast Band
Typical Installations for Donut/Ring Toroids
 AC Cable on F-240 Toroid – 6 turns |
 Ethernet Cable on F-240 Toroid – 7 turns |
 Audio or Mic cable on F240- 12 turns |
Extra Mix 75 Snap On Beads HERE – VERY effective for AM Broadcast RFI