Receive interference Jeep Jk

Discussion in 'Mobile Radio Systems' started by KN4BMK, Sep 23, 2018.

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  1. KK4NSF

    KK4NSF Ham Member QRZ Page

    most likely, you are correct. Unfortunately, the electrical system of my Jeep is beyond my knowledge... and I never could find the source of the problem.
     
  2. KD2AZI

    KD2AZI Ham Member QRZ Page

    My Turn on the Jeep Wrangler installation. I have a 2011 JK, and recently installed a Yaesu 891 with an ATAS antenna. The Alternator whine was gone once I moved the negative power from the battery to the fender ground point. I still get spark-plug noise (via antenna). I bonded antenna base to the back gate, back gate to the body, body to frame and cleaned the mid-section of the exhaust and bonded to frame. I still get spark plug noise. Going to keep experimenting - so far I've made a few contacts 500-800 miles on 40 meters and very pleased. I'm going to take the early posting suggesting and bond the engine block and hood (factory bonded)...and I'll try the tail pipe too.
    Now I just have to remember my vehicle is 'taller' than before with that antenna - already had two minor mishaps...:confused:
     
  3. KF5LJW

    KF5LJW Ham Member QRZ Page

    Where are you connecting for power?
    How are the cables routed?

    Bet you a dollar you have been chasing antenna ghost. There are two ways to get noise in your receiver. The antenna ghost you have been chasing, or your power wiring.

    The Positive/Red power wire goes directly to the Battery Term Post, or if available the Battery Fuse Distribution Block. Many newer vehicles have fused battery distribution blocks either as part of the battery Terminal, or in Master Distribution Block. Just follow the battery cable and see if you have a free fuse position.

    The Negative/Black, there two good places to terminate. One is the battery Negative Term Post. The other is look at the battery Negative Term Post and find the largest wire and find where it terminates. It maybe the firewall, or side wall chassis. It will be secured with a large screw and Dragon Tooth Washer. Pull the screw and washer off, terminate with your conductor, and reassemble connection.

    A few tips:

    A good cable to use for power is 10 x 2 CL rated speaker wire and here is why. Besides the convenience you get fine stranded wire, red and black. The two conductors are tightly twisted together. That keeps the conductors closely coupled and the high twist rate results in a nice CHOKE from the inductance created by twisted conductor closely coupled.

    Do not run power cables with the vehicle cable harnesses as best you can. Cross vehicle harnesses at right angles as best you can.
     
    Last edited: Apr 19, 2019
  4. KF4ZGZ

    KF4ZGZ Ham Member QRZ Page

    All of this is great ..... did you add a few straps from the body to the frame?
    I have helped many fellow off-roaders solve noisy radio problems by simply improving the grounds ...... with the majority of the ground improvement coming to play where they mount the antenna and the antenna mount itself. For some reason, Jeeps are notorious for not being well grounded throughtout.
     
  5. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    The whole key to this, is avoiding any battery monitoring system which may be present. In 99% of the cases (some Subarus, BMWs, and Citroens are excluded), the positive goes to the battery's positive connector. The negative lead, goes to the same chassis connector that the battery ground goes to, wherever that is. Jump points should be avoided, and and main distribution point ALWAYS avoided. Think of it this way: don't use any existing vehicle wiring to power any amateur gear.

    Wiring should be sized for voltage drop, not current handling capacity. Fuse size should be about 60% to 70% of the total peak load, depending on the fuse type. Here the key words are I2T, aka hysteresis.

    All of this isn't rocket science, but it is prudence at its best.
     

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