Aluminum Body Vehicles - Antenna Options?

Discussion in 'On the Road' started by K5KMY, Oct 12, 2020.

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  1. K5KMY

    K5KMY Ham Member QRZ Page

    I’m looking to purchase a Ford pickup truck which has an aluminum body. I would prefer to “hard mount” an antenna to the roof via an NMO style mount, but I have reservations. The biggest concern is the strength of the aluminum roof panel if the antenna were to accidentally hits an object such as a tree branch. I envision the aluminum body being the weak link, resulting in the antenna being torn out of the roof.

    Another option could be to use one of the fender mount brackets which fits between the hood/fender seam and are secured below the hood. I assume this would be a strong mounting option. It would also place the antenna lower to avoid hitting obstacles. However, it would not maximize the antenna’s performance because it would be lower and would not be near the center of the ground plane mass.

    Is my concern of the aluminum body strength overblown? Would placing a steel plate or washer underneath the roof mounting location be sufficient to beef up the strength? Should I abandon the roof mount and accept the potential reduction in performance of another mounting option?

    What have other HAMs done when presented this problem?

    Thanks in advance...

    Ed “Edmo” Morris
    KI5KMY
     
  2. KC0LDH

    KC0LDH Premium Subscriber QRZ Page

    I don't have experience with your aluminum roof specifically, but something to spread out the load, or re-enforce it should be helpful. Breedlove mounts has a selection of heavy duty aluminum mounts that I would consider to for the task. https://breedlovemounts.com/store/ols/products/nmo-roof-mount

    A well selected mount, and a weak antenna may be the best bet. The antenna can act like a fuse, and simply break if strained too much. Antennas are replaceable.
     
  3. K5KMY

    K5KMY Ham Member QRZ Page


    Thanks for the link!

    those guys have several different options to choose from. Additionally, I think I might give them a call to get their opinion on which option might work best for me.

    Edmo
    KI5KMY
     
  4. K6CPO

    K6CPO Ham Member QRZ Page

    All this concern over aluminum bodies trucks is misplaced. Aircraft, including high performance military aircraft such as the F/A-18, F-16, F-22 and F-35 are all made of aluminum and can withstand a lot more stress than an F-150 will ever experience. Ford isn't going to use pure or a soft alloy in their aluminum trucks because it would be too easily dented from just ordinary use.

    I put together military aircraft for fifteen years and I'm certain you will be fine drilling a hole for an NMO mount in the roof of your F-150.
     
    K0UO, AI7PM and N0TZU like this.
  5. K7JEM

    K7JEM Ham Member QRZ Page

    You might look at this thread at another popular site:

    https://forums.radioreference.com/threads/nmo-antenna-mount-installtion-on-aluminum-f-150.391297/
     
  6. WC5P

    WC5P Platinum Subscriber Platinum Subscriber QRZ Page

    Somebody out there (And I don’t remember who it is) makes an antenna mounting bracket that screws on where the center brake light mounts on the back of the cab, then you re-install the brake light over it for a very neat installation. I dismissed it for use on myF-150 because it was absurdly expensive. Might be an option if you want to avoid drilling holes).
     
    WN1MB likes this.
  7. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    If you are concerned about strength then add an aluminum backing plate.

    I've worked on aircraft antennas both with and without backing plates. shrug.
     
    K0UO and NG1H like this.
  8. AI7PM

    AI7PM Ham Member QRZ Page

    The aluminum composite you are concerned about is stronger than the steel that was being used. This isn't beverage can aluminum. Drill it.
     
    N1IPU and K6CPO like this.
  9. N1IPU

    N1IPU Premium Subscriber QRZ Page

    I would not drill it. Use a punch like a greenlee. Even a Stepbit will do damage if your not experienced. I say talk to Breedlove. He has you covered with the Ford aluminum.
     
    K0UO likes this.
  10. KC1MJB

    KC1MJB Ham Member QRZ Page

    If you do use a backing plate, use aluminum. I wouldn't use steel as if moisture gets in there at all the galvanic action will cause corrosion..
     
    K0UO likes this.

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