Old Tip of the Week 8

INSTRUCTIONS ON WHEN TO  USE RF/ EMI SUPPRESSERS
POWER CABLES ACT NOT ONLY AS ANTENNAS,
BUT CAN ALSO CONDUCT INTERFERENCE DIRECTLY FROM OTHER EQUIPMENT.
RADIO TRANSMITTERS
       INTERFERENCE CAN BE CAUSED BY CB OR AMATEUR RADIO TRANSMITTERS BECAUSE OF
       POOR ANTENNA BALANCE, OR FROM RADIATION FROM INTERCONNECTING CABLES.
       FEEDBACK TO THE MICROPHONE CAN OCCUR IF THE OPERATOR IS CLOSE TO THE
       ANTENNA OR IF THE MICROPHONE HAS POOR RF GROUNDING.  A CHOKE ON THESE
       CABLES CAN HELP TO REDUCE THE PROBLEMS.

       AUDIO SYSTEMS, AMPLIFIERS (STEREO), TELEVISIONS, AND
     FM RADIO SYSTEMS

     THE USUAL SYMPTOMS OF INTERFERENCE ARE INTERRUPTIONS FROM MOBILE OR BROADCAST
        RADIO, APPLIANCE NOISE, AND SO FORTH.  THE LONGEST CABLES IN THE SYSTEM ARE THE
        MOST VULNERABLE TO NOISE PICK-UP.  THESE ARE USUALLY THE SPEAKER, ANTENNA, OR
        INTERCONNECTING CABLES.  FOR PUBLIC ADDRESS SYSTEMS OR STAGE SOUND SYSTEMS,
        THE MICROPHONE CABLES, AS WELL AS THE SPEAKER CABLES COULD ALSO BE VULNERABLE
        TO INTERFERENCE PICK-UP.

        COMPUTERS

        RADIO FREQUENCY EMISSIONS CAN  CAUSE INTERFERENCE TO BROADCAST AND
        COMMUNICATION TRANSMITTERS AND RECEIVERS.  THE COMPUTER ITSELF CAN ALSO BE
        SUSCEPTIBLE TO OUTSIDE INTERFERENCE.  LONG CABLES THAT ACT AS ANTENNAS-
        PARTICULARLY TELECOMMUNICATIONS AND NETWORK CABLES-- ARE PRIME CANDIDATES
        FOR CHOKES.

         TELEPHONE SYSTEMS

         RADIO FREQUENCY EMISSIONS, ESPECIALLY CB AND AMATEUR TRANSMISSIONS, CAN
         CAUSE INTERFERENCE TO TELEPHONE SYSTEMS.  THE PHONES THAT ARE MOST VULNERABLE
         ARE THE VERY INEXPENSIVE SYSTEMS ONE CAN PURCHASE AT ANY  DISCOUNT
         DEPARTMENT STORE.  SOMETIMES A PHONE FILTER CAN HELP TO ELIMINATE SOME OF THE
         PROBLEMS.  THERE ARE SINGLE LINE AND 2 LINE PHONE FILTERS AVAILABLE AND THEY
         ARE VERY SIMPLE TO INSTALL IN LINE.  NO SPECIAL WIRING IS NECESSARY.
         ALSO WE CANNOT FORGET THE CORDLESS PHONE SYSTEMS.  THESE ARE ESPECIALLY
         VULNERABLE TO RADIO FREQUENCY EMISSIONS SPECIFICALLY THE 49MHZ SYSTEMS.
         UNFORTUNATELY THE ONLY WAY TO ELIMINATE THE CORDLESS PHONE PROBLEM IS TO
         UPDATE TO THE NEW 900MHZ DIGITAL SYSTEMS. ALSO THE 900MHZ DIGITAL CORDLESS PHONE
         SYSTEMS CANNOT BE PICKED-UP ON ANY RADIO SCANNER.

         PHONE FILTERS CAN BE PURCHASED AT R & R COMMUNICATIONS, INC.  THE SINGLE LINE
         PHONE FILTER COST IS $15.00 AND THE 2 LINE IS $25.00.

         THE RF FILTERS CAN ALSO BE PURCHASED AT R & R COMMUNICATIONS, INC. FOR $5.00 EACH.
         RF/EMI FILTERS ARE ALSO SIMPLE TO INSTALL.  THEY JUST CLIP OVER THE WIRE OR CABLE
         AND SNAP INTO PLACE.  THEY ALSO CAN BE REMOVED AT ANY TIME AND REUSED. THE
         RF/EMI SUPPRESSERS MEASURE 1inch * 3/4inch *3/4inch.

         LOW PASS TVI FILTERS CAN BE PURCHASED AT R & R COMMUNICATIONS, INC. FOR $65.00
         THIS LOW PASS TVI FILTER IS MANUFACTURED BY BARKER & WILLIAMSON.  THIS COMPANY
         IS AN AMATEUR RADIO ACCESSORY MANUFACTURE AND HAS BEEN IN BUSINESS FOR OVER
         SEVERAL DECADES. THE MODEL NUMBER OF THIS FILTER IS FL10/1500 AND WILL HANDLE
         AN OUTPUT POWER OF 1500 WATTS, DOES NOT CAUSE ANY LOSS OF POWER OR HIGH SWR's.
         LOW PASS FILTERS INSTALL IN LINE WITH THE RADIO TRANSMITTER AND ANTENNA.  LOW
         PASS TVI FILTERS ARE DESIGNED TO HELP ELIMINATE SPURIOUS  HARMONICS RADIATED
         BY TWO-WAY RADIO EQUIPMENT THAT FIND THEIR WAY INTO TELEVISION RECEIVERS.

         GROUNDING YOUR RADIO SYSTEM COMPLETELY i.e. ANTENNA, RADIO, ACCESSORIES, ETC.
         WILL DEFINITELY HELP.  THERE IS NO ONE CURE-ALL FOR RF INTERFERENCE BUT EVERY
          LITTLE BIT HELPS.
          PLEASE REMEMBER THAT ALL THE FILTERS AND GROUNDING IN THE WORLD WILL NOT
          HELP INTERFERENCE IF YOU ARE RUNNING A LINEAR AMPLIFIER.