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Diamond Mobile Antenna Help!

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K0GDI, Apr 27, 2020.

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  1. K0GDI

    K0GDI QRZ Lifetime Member #165 Platinum Subscriber Life Member QRZ Page

    Hey all. I just sold a SG7900NMO antenna and they are saying it is missing a set screw. Can anyone tell me what size set screws Diamond uses on their mobile antennas? It would be easier for me to get this answer than to lose shipping and have them return this over a silly screw.

    Any help would be appreciate all!

    73 de K0GDI

  2. AK5B

    AK5B Ham Member QRZ Page

    Don't know what size but it will be metric if that helps. Ace Hardware stocks set screws in metric and SAE sizes; maybe take it there and find one that matches?


  3. K0GDI

    K0GDI QRZ Lifetime Member #165 Platinum Subscriber Life Member QRZ Page

    Thank you,
    If anybody knows the exact size and I can provide that to the person that bought the antenna. Let me know.
  4. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    3mm as I recall, could be 4mm. ACE and TruValue hardware carry them. Buy one of each and send to him. Cheap.
    AK5B likes this.
  5. K0GDI

    K0GDI QRZ Lifetime Member #165 Platinum Subscriber Life Member QRZ Page

    I think you may be right on 3mm, but if someone can confirm?
  6. AK5B

    AK5B Ham Member QRZ Page

    Like Bill said, they're cheap---buy 3 and 4mm and even 1 or 2mm ones if they have them---one is bound to work.

    I would think that Diamond may have a detailed drawing with specs somewhere on the internet if that still isn't enough...
  7. KM6SJO

    KM6SJO Premium Subscriber QRZ Page

    This is a work in progress for me, because I was making an adjustment today and one of the set screws fell on the garage floor and disappeared. I was able to snag a set screw from a Comet antenna and it fit perfectly. I'll follow up here because I hope it will help others. It's likely an M4x3 or M4x4 and I will confirm if those fit. The hex key size is 2mm (0.078"); O.D. of the set screw itself is 0.153" (3.8mm) so I'm thinking the M4 is likely. Close up shows 4 threads, total length 0 .123" so that gives us a thread pitch of 0.7mm which also works out for an M4 screw size. Will confirm after I but a few and give them a try.
    Also included is a diagram of another Diamond antenna, the CR8900A. Note the set screw sizes used. It's unlikely they'd use a wide variety of set screws for mobile antennas.
    Set screw 2.jpg Diamond Antenna diagram.JPG
    KD1JT likes this.
  8. KM6SJO

    KM6SJO Premium Subscriber QRZ Page

    Follow up: Yep, M4 set screws fit perfectly in my Diamond antenna. Nice and snug. Hopefully that will also work for other antennas.

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