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 1.4″ OD/.9″ ID ring toroids as follows:
Mix 77 effective from .1-50 MHz including AM Broadcast band – quantity: 2
Mix 43 effective from 25-250 MHz for general purpose – quantity: 2
Mix 61 effective from 200-2000 MHz for cell phone, WIFI, HDTV, Cable TV interference – quantity: 2
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). For over 30 MHz, 1-3 turns is usually sufficient due the to capacitive effect of multiple turns reducing choking effect.
The rings are also useful for making impedance transformers like 4;1, 9:1, etc.
4:1 impedance transformers (Baluns and Unun configurations) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call CUBE Baluns™ and CUBE Ununs™. All 4:1 impedance transformers use ferrite cores and the kit forms can be configured as a balun with balanced output of 200 ohms or as ununs with one side grounded.
4:1 baluns are designed for 50 ohm unbalanced (coax) input to 200 ohm output (either balanced or with one side grounded).
4:1 Baluns are useful between balanced lines for center fed Zepps, Off-center fed (OCF) dipoles with coax, G5RV antennas, full wave loops, NVIS dipoles that are close to ground and have impedance levels near 200 ohms or high impedance feeds for log periodic beams.
4:1 ununs are useful between coax and vertical antennas, monopole verticals or long wires with load impedances near 200 ohms.