Antenna Rotor RFI Kit - fits all Wired Rotors up to 1/2" cable sizeProduct DetailsYour rotor cable and control box can cause RFI into your radio station and you need to suppress common mode RFI induced into the cable from your antennas. In many cases the rotor cable acts as an unintended counterpoise for your rotated antennas and can cause weird SWR issues since the control cables become part of the antenna,
The SOLUTION is simple: isolate the cable from RFI by adding the Palomar RFI kit for antenna rotors. Add 3 snap on filters near the rotor and another 3 snap on filters at the rotor control box and a ring filter for AC powered rotor control boxes to suppress RFI common mode currents that can affect the antenna SWR and radiation patterns. In addition, these filters may also help reduce station receiver noise since many rotors are connected to the station ground and the rotor cable acts as an additional receiving antenna.
Isolating the rotor cable works on the same principal as isolating coax cable - keep the TRANSMIT signal on the antenna by proving a feed line choke at the rotor itself and keep noise out of the station on RECEIVE by choking the cable at the rotor control box ( by suppressing noise pickup on the cable).
Kit includes 7 filters -six 1/2" snap on filters for the cable and a ring filter for the AC/DC power supply for the control box. Simple to install and cheap insurance to solve both the TRANSMIT and RECEIVE issues caused by rotor control systems.
HF 1-61 MHz coax feed line common mode chokes
Your rotor cable and control box can cause RFI into your radio station and you need to suppress common mode RFI induced into the cable from your antennas. In many cases the rotor cable acts as an unintended counterpoise for your rotated antennas and can cause weird SWR issues since the control cables become part of the antenna,
The SOLUTION is simple: isolate the cable from RFI by adding the Palomar RFI kit for antenna rotors. Add 3 snap on filters near the rotor and another 3 snap on filters at the rotor control box and a ring filter for AC powered rotor control boxes to suppress RFI common mode currents that can affect the antenna SWR and radiation patterns. In addition, these filters may also help reduce station receiver noise since many rotors are connected to the station ground and the rotor cable acts as an additional receiving antenna.
Isolating the rotor cable works on the same principal as isolating coax cable - keep the TRANSMIT signal on the antenna by proving a feed line choke at the rotor itself and keep noise out of the station on RECEIVE by choking the cable at the rotor control box ( by suppressing noise pickup on the cable).
Kit includes 7 filters -six 1/2" snap on filters for the cable and a ring filter for the AC/DC power supply for the control box. Simple to install and cheap insurance to solve both the TRANSMIT and RECEIVE issues caused by rotor control systems.
1:1 feed line Chokes (also known as feed line current chokes, common mode chokes, line isolators, current mode chokes, and 1:1 baluns/ununs) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call a CUBE™. All 1:1 chokes are ferrite based and are designed for 50 ohm coaxial cable input and 50 ohm output. 1:1 Ferrite toroidal or bead chokes have a higher choking impedance than our popular Sleeve Chokes and various models are available for specific frequency ranges and power levels.
1:1 Chokes are useful for choking common mode currents that may flow on the exterior of the coax cable shield while allowing the signals on the interior of the shield and the center conductor to flow unaffected and keeping the common mode current on the antenna. They isolate the coax shield and prevent it from becoming part of the antenna system.
1:1 Chokes are useful between balanced lines for center fed dipoles at their fundamental frequency (468/f (MHz), beam antennas with a 50 ohm balanced driven element, G5RV, loops, yagis, NVIS antennas, mobile installations, portable antennas and anywhere common mode current (or RFI) is a problem. They are also helpful between transmitter and linear amplifier or between linear amp and antenna tuner or as isolation chokes where higher choking impedance is needed (in the range of 2K-7K ohms).
1:1 Chokes are also very useful as feed line current chokes at the “radio end” of the antenna (we call them coax noise filters) where they choke/filter common mode current induced onto the coax shield from radiated waves (from your antenna, and other sources such as DSL routers, computer devices, plasma TVs, etc. originating in your house or your neighbor’s house). For RFI issues see RFI/EMI Solutions for general use or for specific radios and devices.
For best results we recommend a 1:1 choke at the “antenna end” of the coax and a coax noise filter at the “radio end” of the coax. (A side benefit is a reduction in noise level caused by common mode currents). 1:1 chokes are also available as Sleeve Chokes (Slip on or Snap on) for ease of installation and light weight on the antenna.