BUY THIS KIT NOW TO SOLVE YOUR RFI PROBLEMS! WORKS WITH MANY BRANDS OF HAM/COMMERCIAL HF RADIOS INCLUDING ICOM 7300.
This kit will help reduce or eliminate:
1. Radio Frequency Interference (RFI) to electronic devices including audio/video systems, computers, telephones, garage door openers, alarm systems, and home appliances, in your house or your neighbor’s house.
2. RFI from other electronic devices such as switching power supplies, LED and fluorescent lights, battery chargers, Ethernet cables, solar systems, kitchen appliances, and cable/satellite TV systems which generate common mode currents on your radio cables.
3. These filters help cure SWR problems between transceiver and a linear amp and between transceiver and antenna tuner or direct to antenna. The DC power line filter helps keep common mode current out of the power line which could cause interference to other devices connected to the same power source.
These chokes use a ferrite core material that is effective in suppressing RFI from transmitters and receivers experiencing a high noise floor in the 1-300 MHz range.
The ferrite split beads and ring filters are easy to use, don’t require modification of the protected equipment and work in almost all cases, even when plug-in filters fail.
Kit Includes 2 noise reduction ring filters for coax and AC/DC power and 3 snap on filters for I/O cables. Quick installation - immediate RFI/noise reduction. No radio mods required. Snap on ferrites may be either 4 or 6 sided depending on inventory - they have identical electrical properties..
For additional RFI suppression, use a feed line choke at the antenna feed point to suppress common current on the coax feed line during TRANSMIT and a CMNF-500-50 coax noise filter at the radio end of the coax to reduce common mode noise during RECEIVE.
If you use a linear amplifier use a Palomar Engineers amplifier RFI kit for additional RFI interference suppression.
We stock RFI/Noise Reduction kits for most brands of radio transceivers and generic kits for others
Visit our website for all your RFI/noise reduction needs!
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