Elecraft K4 Transceiver RFI and Noise Reduction Kit, RFI Range 1-60 MHz, 24 FiltersProduct DetailsMPN: RFI-ELECRAFT-K4Type: NEWCountry/Region of Manufacture: United StatesRFI Suppression Range (MHz): 1-60 MHz# Ferrite Filters: 24Enclosure Size (inches): n/aTypical Use:: AC/DC power, RF output x 4, multiple I/O linesThe Elecraft K4 is an exceptional radio and deserves an exceptional RFI and noise reduction kit which we have designated as the "ELITE" series of Transceiver Kits. This kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the multiple coax connectors of your radio, the AC power input, USB, ethernet, Audio, HDMI, amplifier ALC/Send, mouse, mic and additional interconnect cables. The ELITE Kit has 6 ferrite ring (1.4" ID) filters and 18 ferrite snap on (1/2") filters and instruction manual. Similar kits available for other manufacturers.
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 (MC-1-3000) at the antenna feed point to suppress common current on the coax feed line and a coax noise filter (CMNF-500-50) at the radio end of each coax input to reduce common mode noise.
If you use a linear amplifier use an amplifier RFI kit (RFI-LA-GAC) for additional RFI interference suppression.
MAXI-CHOKER Coax Line Isolator/Balun, 1-61 MHz, 1.5/3KW, SO-239 In/Stud Output, FLAGPOLE OCF, G5RV, ZS6BKW, BN4000 Replacement, Ladder Line-Coax interfaceMAXI-CHOKER Coax Line Isolator/Balun, 1-61 MHz, 1.5/3KW, SO-239 In/Stud Output, FLAGPOLE OCF, G5RV, ZS6BKW, BN4000 Replacement, Ladder Line-Coax interfaceSKU MC-1-1500LL$89.95
The Elecraft K4 is an exceptional radio and deserves an exceptional RFI and noise reduction kit which we have designated as the "ELITE" series of Transceiver Kits. This kit is designed to be installed on your radio transceiver to reduce Radio Frequency Interference (RFI) caused by common mode current on the multiple coax connectors of your radio, the AC power input, USB, ethernet, Audio, HDMI, amplifier ALC/Send, mouse, mic and additional interconnect cables. The ELITE Kit has 6 ferrite ring (1.4" ID) filters and 18 ferrite snap on (1/2") filters and instruction manual. Similar kits available for other manufacturers.
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 (MC-1-3000) at the antenna feed point to suppress common current on the coax feed line and a coax noise filter (CMNF-500-50) at the radio end of each coax input to reduce common mode noise.If you use a linear amplifier use an amplifier RFI kit (RFI-LA-GAC) for additional RFI interference suppression.
TECH NOTE: We also stock RFI kits to protect effected devices such as garage door openers, computers (laptops, desktops), dsl/cable routers, ethernet hubs and many more devices. If you run a high powered RF amplifier in your ham station also consider a linear amp RFI kit which will cut down RFI transmitted by your station. Remember there is always a “transmitter” and a “receiver” of RFI and the quest is to find and choke the “path” the RFI has selected – you need to add ferrites to both the transmitting side and the receiving side to eliminate RFI problems. The RFI-HTS kit only helps suppress RFI on the receiving side.
Typical RFI Problem/Solution:
Hello, I am Larry, a ham operator and I am having interference issues with my Direct TV system. My station is a FT450D through an Ameritron ALS-600. From the amp through a coax switch to choose between an OCF dipole or an Hustler 5BTV vertical. Any power over 100 watts and my DTV goes off the air and must completly reboot/format. Coax is RG-8. The DTV dish is pointed away from the dipole and separated by about 25'. DTV was totally useless! They suggested I not talk on the radio while she is watching TV! Please help me with a reasonable, cost effective soultion. (The wife gets really pissed when I shutdown the tv!) Thank you, Larry
Hi Larry,
Your RFI problem is quite common and is usually a sign of either a radiating coax feed line or reception of your radiated signal (source) by the Direct TV (the victim) through either the AC power lines acting as “antennas” for your ham signal or the coax braid of the satellite antenna acting as an antenna for your signal.
The solutions are straight forward:
1. To make sure your feed line is not radiating you need a feed line choke at each antenna feed point (also makes your antenna work better since it is not using the coax as part of the antenna). You can use our simple Kit 110 with 5 snap on chokes on each antenna for this purpose. Part # Kit 110 at $27.50 each – one for each antenna. These chokes will keep your feed line from radiating and coupling into your ac power lines. INFO HERE
2. The radiation from your antennas themselves may also be getting into the ac power lines and coax braid of the Direct TV antenna so you need to protect the victim receiver. Depending upon the sophistication of your direct TV setup (e.g. home theater, dvd, tape player, sub woofer speakers, etc), the path of the RFI may be coming thru the AC power lines of any connected device to the video including the video monitor itself! To help solve this problem we have a home theater RFI kit for up to 5 devices (you need a minimum of two – one for the Direct TV receiver(AC and coax input) and another for the video monitor AC power lines and HDMI or video input cable. Our kit part # is RFI-HTS. INFO HERE
These items should help reduce the RFI and let you operate on the air while your wife watches TV.
Bob Brehm, AK6R
Chief Engineer