Strange noise when stationary

Discussion in 'On the Road' started by K6SRF, Nov 13, 2017.

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  1. K6SRF

    K6SRF XML Subscriber QRZ Page

    I connected my FT-857D to the Jeep battery and every time I keyed to transmit on 40 meter, I would hear clicks from underneath the vehicle. This wasn't happening on 20 meters. The engine wasn't running. After I heard that a few times I stopped trying.

    Any ideas why that would happen?
     
  2. W7UUU

    W7UUU QRZ Lifetime Member #133 Life Member Platinum Subscriber QRZ Page

    Sounds like your RF on low bands is getting into the Jeep's wiring harness and keying some relay inside the vehicle. Many automotive electrics never fully "turn off" but rather stay in a low-current "sleep mode" awaiting you to turn the key and start the motor. My guess is you're keying one of these "sleeping relays" and that's the click you're hearing.

    What sort of antenna are you using?

    Dave
    W7UUU
     
    N6QIC likes this.
  3. K6SRF

    K6SRF XML Subscriber QRZ Page

    Dave, there must be something like that. I'll have to work on bonding the Jeep, and then see if it still does it. If it does, I might not use 40 meters while mobile. I know of a guy whose Jeep would think it's in 4Lo when keying a certain band.
     
  4. W7UUU

    W7UUU QRZ Lifetime Member #133 Life Member Platinum Subscriber QRZ Page

    Yikes! That would indeed be bad :eek:

    I would definitely solve the problem before you discover something really bad happening while mobile!

    Dave
    W7UUU
     
  5. N6QIC

    N6QIC Premium Subscriber QRZ Page

    Do you get the same results with the engine running?

    I would try a test, powering the radio in the jeep with an AC power supply and se if you still get the clicking.

    That should tell you if it is RF getting into the electrical system in the jeep causing the clicking, or if it is something with the electrical system or the battery in the jeep. If the clicking goes away then I would go to a good car stereo shop and ask them for advice.
     
    Last edited: Nov 13, 2017
  6. K6SRF

    K6SRF XML Subscriber QRZ Page

    I haven't tried with the engine running, I didn't want to mess up something and get stranded. I should try it at home.
     
    N6QIC likes this.

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