Install of Scorpion SA-680 mobile HF antenna

Discussion in 'Mobile Radio Systems' started by KC7YRA, Jun 18, 2012.

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  1. KC7YRA

    KC7YRA Ham Member Volunteer Moderator QRZ Page

    Ok, everything was spread around from my past posts, so here it is for all to see.

    Several weeks ago, I ordered a Scorpion antenna from Ron. It finally got here last week and I got it installed. Here is what I had to do.

    Unpacking the antenna is a chore in itself. Here is my buddy Josh (KA7JUN) unpacking his. Multiple screws, wood plugs, several page instructions to get it out. VERY VERY well (and intelligently) packed. Don't let this critter fool you. It is all of the 18lbs that Ron touts. The lexan coil cover is extremely rugged. The whole antenna feels like you could bash down a tree with it.

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    I decided to build a custom mount for the bed of my Toyota Tundra. The truck comes with factory installed, threaded mounting holes for the addition of bed rails and other accessories. Extremely strong and easy to access.

    I started with .25 inch steel plate and several pieces of strapping.

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    Cut an formed to fit in the corner. I ended up gusseting the 1/4 inch plate to strengthen it for the massive torsional load the antenna would present.

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    Drain hole cut in the corner and painted. I used high temp engine type paint then baked it in the oven to set it. About as strong of a coating as most folks can get without sending it off to a powder coat place.

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    The antenna came and got mounted. It uses a .75 inch hole, through which a piece of stainless allthread passes. This holds a quick disconnect "plug" that goes up in the base of the antenna. I had a small problem where the antenna tried to abandon ship after a few miles of washboard road. I ended up modifying the install with some loc tite and a nylock nut. Overall, seems quite strong. 1 inch braid bonds the antenna to the truck. The hood, bed, body and exhaust are already bonded with the same strapping. The antenna is controlled from a custom box I built in the cab. I have both 12v and 6v ay my disposal so I can make very finite adjustments. Works quite well. In the photos, you can see my home made shunt coil. With it, I can go wherever I want and the antenna gets a match under 1.5:1

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    Here is Josh's mount that I built him. Since it is mounted on an un-supported extension, this is 3/8ths plate that I welded up for him. He wanted his set lower in the bed, hence the mounting scheme.

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    I have been using it for a few days and don't have much to say. Whenever I'm on the air, the bands are DEAD. I originally thought it was the antenna but scanning the bands at home with my beam showed no real difference.

    In closing of this first post, let me commend Ron at Scorpion. I have NEVER had such great communications with a company EVER. Multiple phone calls both to and from Ron. He is genuinely interested in how things are going and what the customer wants. I have already had a few ideas to toughen up the antenna and Ron chatted with me on the phone about them. If he decides to use them, I dunno. But, he LISTENED and discussed like a true professional who wants to make his product better. A+++++++ for Ron and Scorpion.


    Brad
     
  2. M0GVZ

    M0GVZ Ham Member QRZ Page

    An excellent write up there and a brilliant installation. I'd like to thank you for saving me some money as I was going to buy one of these but unfortunately I haven't really got anywhere strong enough on my car to put it - European cars aren't really built to mount 18lb antennas to. It has however spurred me on to work on the XYL to get permission to buy a "radio truck".
     
  3. KC7YRA

    KC7YRA Ham Member Volunteer Moderator QRZ Page

    Thanks! That's too bad about the Euro vehicles being to light duty however. Scorpion does make the smaller version of this antenna that is a few pounds lighter.

    As for mounting it, do you have friends with welders and metal working capability? If so, you could get a frame style mount built in a few hours. I don't know if welders and metal yards are as common there as they are here.

    Brad
     
  4. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    Just for the record, the braided ground strap you didn't do you any good. If it did, they the original mount wasn't properly attached to the bed.

    One more thing. What about the motor lead and coax choke specs???
     
  5. AF6LJ

    AF6LJ Ham Member QRZ Page

    That looks great.
    I love your bed mount that was nicely done.
     
  6. KC7YRA

    KC7YRA Ham Member Volunteer Moderator QRZ Page

    Originally, the mount was having problems being DC connected to the rest of the truck. All of the threaded mount holes were painted and I had some issues. I ended up using a tap set and cleaning out the threads. I did that on all of the threaded holes. I had initially used the braid as a way to ensure the DC ground. At this point though, I could eliminate the strap.

    As for the motor and coax chokes, I pretty much did as you describe on your site. Mix 31 ferrite with a 3/4 inch hole. I wrapped the control wires as you can see in one of the pics. I also did 5 or 6 turns of the RG-8X with 2 beads on that. My coax runs on the fuel rail and in previous installs, I would actually kill the fuel pump if I operated on 80 meters. With the extra care on choking that common mode current, I can now run on 80 just fine. Truck actually stays running LOL.

    Brad
     
  7. KC7YRA

    KC7YRA Ham Member Volunteer Moderator QRZ Page


    Thanks. It's nice to be able to weld LOL.

    BRad
     
  8. AF6LJ

    AF6LJ Ham Member QRZ Page

    While Dad taught me to solder and braze, my brother was taught to weld.
    Arc weld that is.....
     
  9. AC4RD

    AC4RD Ham Member QRZ Page

    I'm NOT going to make a joke about a "brazin' woman." I'm not, I'm not, I'm not! ;)
     
  10. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    Brad, that is the correct way—metal to metal! Paint does have a way of causing all sorts of contact problems.

    There is a commercial mount made for Honda's Ridgeline truck, and connected via a bolt passing through the tie down cleats. Problem is, the paint on the tie downs is tar-based, and about 1/32 of an inch thick. Every one I know who has used one has had common mode problems. This is why I ask about the chokes. When it comes to common mode, overdone is a whole lot better than under done!

    Good job my man!

    By the way, send me a few photos for the gallery.
     
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