Old Raritan battery charger causes vhf interference on broadcast

Discussion in 'Electrical Systems' started by sdowney717, Aug 13, 2019.

  1. sdowney717
    Joined: Nov 2010
    Posts: 955
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    Location: Newport News VA

    sdowney717 Senior Member

    You can hear an actual hum like sound when pressing mike, and automated radio check by SeaTow plays back your voice and its definitely there.
    If I flip off charger, the interference is gone, interference is only on broadcast and only on a radio, nothing else seems affected.
    IF I turn it off by ignition shutdown, look at right side schematic 12 vdc there turns it off temporarily, the interference is gone.
    Someone suggested putting radio dc wires right at the battery, which I can try, but I doubt will fix it.

    I bought a cheap DC amp sense relay. See a radio uses far less amps to listen than broadcast, so use the relay to detect increased amp draw to maybe 2 or 3 amps to turn off battery charger output. When not broadcasting, radio might use 0.5 amps.
    I will have to set up relay for when radio is on low power not high.
    And have to use a diode (#7) to isolate from backpowering the ignition to the engine, diode will go in the output from relay to ignition shutdown connection on the charger, just like the schematic shows those 2 diodes, this will be a third diode, and will work the same way.

    I have a little steel relay box about 4 x4 x4 " with a lifting hinged cover I will put this board in.
    US $7.01 50% OFF|12V 0 10A DC Current Detection Module Current Sensing Detecting Delay Relay Control-in Instrument Parts & Accessories from Tools on Aliexpress.com | Alibaba Group https://www.aliexpress.com/item/4000028199776.html?spm=a2g0s.9042311.0.0.3b794c4dVApNcc

    I am posting schematic that shows how it works. convertordiagram2.png
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