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
Purpose. Simple, Effective RFI Kit consisting of 3 Solar Noise Filters (Mix 75) with 1/2" ID, for use on 3 Input/output ports such as Solar Panel Array input, Battery and Excess Load ports. Noise filters suppress noise and RFI at typical frequencies generated in solar charge controllers.
This kit is designed to choke common mode currents going into or exiting from your charge controller and they help keep common mode current out of the power line (or into your radio through the battery) which could cause interference to other devices connected to the same power line if not suppressed.
THE RFI KIT FILTERS ONLY SUPPRESS COMMON MODE CURRENT (SIGNALS) THAT ARE COMMON TO ALL WIRES IN THE CABLE, AND DOES NOT EFFECT INDIVIDUAL DIFFERENTIAL SIGNALS ON EACH WIRE. THE FILTERS HAVE NO EFFECT ON THE NORMAL SIGNALS CARRIED WITHIN THE CABLE.
If you use an inverter and experience RFI noise use additional mix 75 ferrite filters on the input and output of the inverter to help suppress this noise.Install both positive and negative wires through the same filter.
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 for higher choking (under 30 mHz).