The simplest, most cost effective feed line choke is a ferrite ring installed as shown in the picture (at the antenna feed point) to stop feed line radiation or at the radio end of the coax to suppress common mode coax noise current on the coax braid.
Great choke for log periodics, HF beams, Transceiver/Amp isolation
Improves antenna pattern by preventing your dipole from becoming a tripole
Suppresses pesky coax braid radiation and RFI
Reduces coax braid common mode current up to -40 dB ( 6 “S” units) on receive
Use one choke for each antenna feed line
Add a double female barrel connector to act as an “extension” of the existing coax.
HF Transceiver RFI/Noise Reduction Kit, RFI Range 1-300 MHz, 5 Filters
| Quantity | Price per item | Discount |
| 2 items | $36.95 | 8% off |
| 10 items | $32.95 | 18% off |
| 100 items | $29.95 | 25% off |
BUY THIS KIT NOW TO SOLVE YOUR RFI/EMI NEEDS! WORKS WITH MANY BRANDS OF HAM/COMMERCIAL HF RADIOS
Standard Kit Includes noise reduction ring filters for coax, AC/DC power and 3 snap on filters for I/O cables covering RFI range of 1-300 MHz. Quick installation - immediate RFI/noise reduction. No radio mods required.
Use With all brands including:
Icom: IC-706, 718, 746. 756, 7100, 7200, 7300, 7400
Kenwood: TS-480
Yaesu: FT-450, 817/818, 857, 891, 897, 950, 991A, 1200
If you have a high end radio with multiple antennas, and more than 3 I/O cables, use our Deluxe Transceiver RFI Kit, RFI-XCVR-DELUXE
Purpose
The RFI kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the outside of the coax braid at the output of your radio and AC/DC power cable. Additional chokes are included to reduce common mode currents on 3 more transceiver cables including computer control, audio and another.
This kit will help reduce or eliminate:
1. “Hot mic” RFI caused by poor grounding of antennas or common mode currents from linear amps feeding unbalanced (coax fed) antennas without baluns/line isolators.
2. RFI to neighbor’s electronic devices including audio/video systems, computers, telephones, garage door openers, etc.
3. RFI to your other radios, audio/video systems, computers, telephones, etc.
A side benefit is a reduction in noise floor in your receiver depending on the amount of noise being introduced by common mode currents (which are blocked/reduced by the chokes in this kit).
These chokes use a special mix of ferrite core material that is effective in suppressing radio frequency interference from transmitters and high noise floor on receivers.
The snap on beads are easy to use, don’t require modification of the protected equipment and work in almost all cases, even when plug-in filters fail.
Use of the chokes often helps cure SWR problems between transceiver and a linear amp and between transceiver 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.
Included are the following chokes and installation guidelines:
RF Input/Output: 1.4" ID ring filter – 5-9 turns of RG-58/RG-8X size coax cable through center
AC/DC Input: 1.4" ID ring filter – 3-7 turns of AC/DC power cable through center
3 additional I/O cables - 1/2" snap on with 1-2 turns through center. Multiple wires can share the same filter.
If you use a linear amplifier use an amplifier RFI kit for additional RFI interference suppression.
