Getting RF on HF Mobil into the truck

Discussion in 'On the Road' started by W9KJO, Jul 21, 2020.

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  1. W9KJO

    W9KJO Premium Subscriber QRZ Page


    I have a 2017 GMC 2500HD. I installed a IC706MKIIG and a little Tar Heel antenna. The antenna is mounted to the back of the bed with a Ham Stick swivel mount. I have an Aux Battery with torroids in the DC feed and the battery is only for the rigs. I have ground flat strap on the exhaust, to the case of the truck computer under the hood, on the hood, and to the bracket for the antenna.

    When I key up on almost any band all the warning lights turn on on the dash. Even at a low 50 watts.

    this truck install has been very difficult. This setup worked great in my old 1998 Expedition, but this newer truck is difficult.

    any advice will be greatly appreciated.

    Walter, W9KJO
  2. KC0LDH

    KC0LDH Premium Subscriber QRZ Page

    Walter, I'm sorry you have having trouble.

    I do not have any first hand experience with the GM/Chevy products, but would start with the Mfr. Body-Builder manuals. They may have some precautions, details or other instructions how to install accessory 12v, or radio systems. I'm sure that the truck is used in Police, EMS, or similar duty's so there is something to relate to. At the very least, its got some good information for how the thing is wired, and is supposed to work. 5W4 Specification Guide 2017.pdf
    K0UO likes this.
  3. KC0LDH

    KC0LDH Premium Subscriber QRZ Page

  4. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    I feel your pain I went from an 08 GMC Duramax to a 2017 Chevy Duramax three quarter ton. I also have an install in a 2015 Chevy Duramax
    When I'm using HF even my ABS brakes would lock up/ quite scary

    When I first installed my truck even shut down a couple of times also airbag warning light also very scary.
    After several years of adding grounding straps everywhere probably 50 feet and close to 30 or 40 toroids (which I'm not sure all the toroids) have really done that much good, I am finally able to operate with only a few problems even while running the AL500

    And don't blame Chevy/GMC, my son's F-350 Ford has done the same thing/ warning lights and RFI.

    The Good thing is that GM has really cleaned up the RFI coming out of the trucks system, I hardly detect any on any of the low-band frequencies.
    The Ford has terrible IFR coming off of computers and injection systems.

    I suggest you go to Alan's Applebee's site
    He has information about installs using Tar H and the other screwdriver, it is an absolute must read for any install, you may not have even connected your power lead properly charging your other battery, all new vehicles have sensors on the power leads coming off the battery.

    All new vehicles are extremely hard to get HF to work but you will make it happen with some preservation.
    If you haven't already done it, it is an absolute necessary to ground the bed to the frame in all four corners with straps, the mount, and the tailpipe muffler system in probably three or four places, even a hood needs a ground strap (not just a wire). Make sure you grind down to bare metal and put appropriate coating on the connections the frames are coated with insulated material.
    I don't know how you have mounted the Tarheel I'm using a similar antenna the Scorpion/ posts some photos
    Read Alan's site

    Keep us posted a Good HF Mobile is worth it
    Last edited: Jul 21, 2020

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