The Ferrite Ring Combo Pack is a convenient solution for troubleshooting RFI/EMI from unknown frequencies or multiple frequencies that require multiple suppression mixes. Included in this combo pack are ten 2.4″ OD/1.4″ ID ring toroids as follows:
Mix 75 effective from .15-10 MHz including AM Broadcast band – quantity: 3
Mix 31 effective from 1-300 MHz for general purpose – quantity: 4
Mix 61 effective from 200-2000 MHz for cell phone, WIFI, HDTV, Cable TV interference – quantity: 3
Individually wrapped and labeled with effective RFI frequency range for easy identification
The ring toroids are useful for AC/DC common mode choking with multiple turns as shown below
AC Cable on F-240 Toroid – 7 turns |
DC Cable on F240 – 4 turns |
The ring toroids can also be used on coax or signal lines as shown below:
RG58 12 turns on FT240 |
Ethernet Cable on F-240 Toroid – 7 turns |
For RFI/EMI wrap as many turns as possible (usually 6-12) for higher choking (under 30 MHz). For over 25-100 MHz, 1-3 turns om Mix 61 is usually sufficient. Chokes can also be cascaded in series to offer a broader frequency range.
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.