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
Available as a Unun for 50 ohm coax to 75 ohm coax or 75 unbalanced load or as a Balun for 50 ohm coax to balanced load such as a low (less than a wavelength high) dipole with either side eye bolts and halyard hoist or as post mountable top studs output.
This is an impedance transformer for 50 to 75 ohms and may require a additional feed line choke to keep common mode current off the coax braid.
CB-1.5-1500EB is useful for a dipole center feedpoint for low dipoles with 75 ohm antenna impedance.
Top stud version also useful for 75 ohm ladder line to coax interface
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).