BUY THIS KIT NOW TO SOLVE YOUR RFI/EMI NEEDS! WORKS WITH MANY BRANDS OF HAM/COMMERCIAL HF RADIOS WITH DUAL ANTENNAS OUTPUTS AND MULTIPLE I/O CONNECTIONS INCLUDING THE YAESU 991
Kit Includes 3 noise reduction 1.4" ID ring filters for two coax cables, AC/DC power and 5 1/2" ID snap on filters for I/O cables covering RFI range of 1-300 MHz. Quick installation - immediate RFI/noise reduction. No radio mods required.
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 split beads 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 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.
For additional RFI suppression, use a feed line choke at the antenna feed point to suppress common current on the coax feed line and a coax noise filter (like our CMNF-500-50) at the radio end of the coax to reduce common mode noise.If you use a linear amplifier use a Palomar Engineers amplifier RFI kit for additional RFI interference suppression.
SLIP-ON FERRITE BEADS
Baluns are used to connect balanced antennas to unbalanced transmission lines (Coaxial cable) and Ununs are used to connect unbalanced transmission lines to unbalanced transmission lines or unbalanced antennas (e.g. verticals). In the case of 1:1 baluns the input is usually an unbalanced coax cable and the output load is a two terminal balanced load like an antenna. Ununs are also called line isolators, feed line chokes, and 1:1 coaxial baluns (incorrectly). 1:1 Baluns and ununs stop common mode currents (flowing on the outside of the coax braid due to skin effect) when they are located at the antenna feedpoint. They can also be used as “line isolators/chokes” anywhere along the cable to suppress flow of induced RF (antenna near field radiation and neighborhood noise pickup) which helps suppress RFI into the radio receiver/transmitter. For best results, put one at the antenna feed point connection, and one at the radio room entrance, and for difficult common mode current cases, one every 1/4 wavelength along the antenna feed line. For low (below 3 MHz) frequencies, use two 5 bead baluns in series to double the choking impedance or order the 10 bead or 15 bead version for higher choking power.