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
Linear Amplifier RFI Kits
LINEAR AMPLIFIER RFI KITS
Palomar Engineers has RFI kits for many brand specific linear amplifiers as well as generic RFI kits for both AC powered and DC powered linear amplifiers.
Purpose. These kits are designed to choke common mode currents going into or exiting from your rig. Chokes are supplied for the RF In, RF Out, Relay Cable, and AC/DC power line. Use of the chokes often helps cure high SWR problems between exciter and power rig or between power rig and antenna tuner or direct to antenna. The AC/DC power line choke helps keep common mode current out of the power line which could cause interference to other devices connected to the same power line if not suppressed.
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).