Consumer electronics are in every home and are subject to radio frequency interference (RFI) from each other and outside sources. Palomar has developed effective RFI suppression kits for various consumer products that are easy to install and require no internal modification to the equipment.
The Problem
What causes RFI?
Strong signals from nearby amateur radio, CB, FM and other “transmitters” (such as microwave ovens, cell phones, desktop, laptop, and tablet computers, wireless phones, baby monitors, fish tank heaters/pumps, etc) that are picked up by long wires (“antennas”) running through the house electric power wiring, telephone cables. alarm system wires, speaker wires, device interconnects, etc. These “antennas” feed the interfering signals into the TV, telephone, stereo, alarm systems, computer and electronics devices causing them to halt operation or act intermittently.
How to cure RFI
RFI can be stopped by suppressing the signal from the radio “transmitter” AND suppressing the signal on the receiving “antenna” feeding the affected device. With the RFI suppression kits, you are protecting the devices on the receiving antenna by running all input and output wires entering the electronic device/system through ferrite beads or rings right next to the device. Ferrites do not affect the signals going through the wires but they resist the passage of common mode RFI reducing the RFI signals on the “antenna” wires and stopping the RFI from falsely triggering the effected device. Some lines may require multiple ferrite rings or beads to be most effective. Also the more turns around and through the ring, the more effective the RFI filter.
The Solutions
Click on the RFI Solution link for the electronic device/system to be protected:
Home Theater System (HDTV, Sub-woofer, Stereo, Speakers, DVR, Gaming)
Home Alarm System including smoke detectors
Computer RFI Kits (Laptop, Desktop, Router, Network Hubs, etc)
Garage Door Opener
Generic Household RFI Kit
Treadmill and other exercise equipment
AM Broadcast Interference Kit
FM Broadcast Interference Kit
Telephone Line RFI Kit
Cell Phone Headphone RFI Kit
Lawn Sprinkler System RFI Kit
Wall Wart DC Power Supply Filter Kit
Christmas Light RFI Kit
Dishwasher RFI
Problem: Dishwasher operation failed or intermittent after transmitting on 80 meters using linear amplifier. Problem traced to 80 M dipole feed line radiation near dishwasher location and unprotected dishwasher circuitry.
Solution: CB-1-5000EB feed line choke on dipole to suppress feed line radiation AND FSB-31-1 snap on choke on AC line of new dishwasher (old dishwasher circuit boards continued to fail due to overload of common mode RF into AC line cord)
Clothes Washer/Dryer RFI
Problem: Considerable noise level on ham bands when either clothes dryer or washer was operated. Problem traced to AC line cord to washer (110VAC) and 240 V electric washer line cord.
Solution: Install FSB-31-1 snap on choke to AC line cords of dryer and washer with 2 turns through center of choke. Noise level significantly lowered in ham receiver.
HVAC/Air Conditioning/Heating RFI
Problem: RFI on ham bands, AM and sometimes FM and TV due to interference when heater/air conditioner is running. Many newer units use variable speed motors (with PWM controllers that use square waves rich in harmonics that may be radiated) and RFI may be radiated through the thermostat wires or the AC cable to the unit.
Solution: Install FSB31-1/2 snap on chokes (get a 10 pack as you will probably need to use them on multiple wires) on thermostat line beginning at heater/air conditioner and install F240-31 (1.4″ hole) ring ferrite or F400-31 (4″ hole) on the AC power cord with multiple turns. In some cases multiple snap on beads may be required on the thermostat lines and additional bypass caps (,oo1 on each thermostat line) may be required. Shielding of the motor controller and ferrites on the motor controller to motor cable may also be needed. This RFI issue has been a known problem on TRANE units and many other brands but no simple solution has been found other than to start adding chokes to all input/output connections on the unit until the RFI is suppressed to a satisfactory level.