Radio Tower Trailer
RSS | Subscribe | Contact Us | Advertise | About Us
Results 1 to 11 of 11
  1. #1
    Join Date
    Jul 2005
    Location
    California
    Posts
    630

    Radio Tower Trailer

    I'm new to the forum, but I figure this is a better introduction than anything else. I just finished building and testing a tower trailer for ham (amateur radio) stuff shown here:

    http://www.harm.org/~halbritt/gallery/TowerTrailer

    A friend of mine received a visit from his neighbor who noted the radio gear on his roof. She asked him if he'd like to have a ~50' telescoping tower, all he had to do was come and get it. He called me in and that's what we did. It wasn't much of a bargain as it took several weekends over the course of a few months to get the thing off of her house and out of her backyard which was entirely occupied by a swimming pool and a gazebo.

    My friend decided that he wanted to put the tower on a trailer for portable operation and ease of setup, so I made a few sketches and this is what we ended up with. It was welded up entirely with a Millermatic 135 using .30 GMAW and .35 FCAW for the thicker stuff. I used 2x6 .120 wall for stiffness and the ability to get good penetration with such a small welder. I also used some 2x2 .160 wall, and 2.5x3.5 .250 wall for the tongue. There's also some 1/4" and 5/16" plate in there. The total final weight is about 1500Lbs with the tower on a 3500Lb axle. The jacks, winches, axle, and fenders are standard commercial trailer stuff.

    The most complicated bit was the hinge that the tower rides on. I was able to find a 1.250" rod at the scrap yard and a piece of 2" DOM that it fit almost perfectly into. The machinist knocked about .010" off the rod to smooth it out and I hit the inside of the pipe with a hone and then added a grease fitting. Unfortunately, I don't have any really good photos of the hinge. The fit was so tight, that there was no discernible axial deflection in the unguyed tower while it was fully extended and being buffeted by 30+ mph gusts of wind.

    Obviously, it's not finished as is the case with most projects. There's still a few embarrassments that I'd like to grind on a bit. It'll also need to be prepped and painted. It has been tested (ARRL field day) and it works well. With jacks on four corners, it was pretty straightforward to get assembled, balance, and mount the axle after the fact. I think this contributed a great deal to the towing characteristics of the trailer. It tows like a dream, tracks straighter than my truck will go, and handles corners like a sports car. I was worried about ground clearance and considered adding casters on the back, but after towing it for a little over 700 miles I haven't bottomed out yet.

    The MM135 was able to handle the .120 wall pretty well, but it really starts to suck wind on anything thicker. Good prep was critical and I was running it as hot as it would get most of the time. I also used the $50 HF chop saw that some folks have complained about. It's really not as bad as people have have made it out to be. It doesn't have much power, certainly not the 2HP that it claims, but I was able to cut most things accurately and in a reasonable amount of time. I just OA-cut the plate, which was a pleasure compared to the chop saw.

  2. #2
    Join Date
    Mar 2005
    Location
    Carrollton GA
    Posts
    2,329
    That's a really smart design. It looks like you were really giving the millermatic a workout and getting your money's worth out of it.
    Smithboy...
    if it ain't broke, you ain't tryin'.

  3. #3
    Join Date
    Jun 2005
    Location
    Upstate, S. Carolina
    Posts
    70
    You think the F.C.C. would mind if I borrowed it to broadcast my "underground" radio station?

  4. #4
    Join Date
    Jan 2005
    Location
    Washington State
    Posts
    61

    Radio Tower Trailer

    It's amazing how a mission in mind generates such creativity. Beautiful work, definitely something to be proud of. Good Job!

  5. #5
    Join Date
    Feb 2004
    Location
    Ft. Wayne, IN
    Posts
    42
    I have wanted to build one of these for years. Just never have gotten around to it. It looks great. I have been a ham since 1992. It is hard for me to believe I have been an Amateur Extra since 1994 (18 yrs old). I love seeing ham radio and welding together. It is a beautiful thing.

    Jon (N9OBL)

  6. #6
    Join Date
    Jul 2005
    Location
    California
    Posts
    630
    Thanks for all the kind remarks.

    There's still a bunch to do. It needs to be prepped and painted as I already stated. I'd also like to re-work the lights such that they're recessed into the rear. They were done like that for simplicity in having the rear clearance light (required for >80" vehicles) integrated with tail lights. I think I'm just going to recess the tail lights and put the rear clearance light on the fender.

    I also would like to design and build outriggers of some sort. I'm not exactly sure how much wind loading it can take unguyed, but there is some desire to increase the wind loading ability. At this point, it's been through a couple of serious storms with a full size, five element, 20 meter yagi and it's never once moved.

  7. #7
    Join Date
    Jul 2005
    Posts
    12
    Iwas just wondering how stable the tower is on a windy day ?I'm also a ham radio operator since 1980 and do welding for a living .I had in mind a project like this after seen a project on one othose ham radio magazines QST maybe .And I'm sure you are the same people on that article.Any way what a great project . I own a 48 ft.Rohn free standing tower and was plaming just to build a base above ground .instead of setting it on a concrete base . Any ideas? I think I'm a little better at fabricating and weldind .but lousy at designing.Years ago at a field day one of the guys ttied to do something similar .He fashioned some kind bracket to the rear bumperof his car to support also a telescopic tower .But since he did not have much experience as a welder his welding beads cracked and the tower almost fell. If Iever get arround to build a base and set the tower and the yagy .I will post some pics

  8. #8
    Join Date
    Dec 2005
    Location
    Avon, Ohio
    Posts
    120
    Reminds me once I made a gin pole for a guy who installed those things.

  9. #9
    Join Date
    Jul 2005
    Location
    Western WA
    Posts
    187

    Good Job!

    Howdy Howdy! GOOD JOB! I was thinkin gabout your guying options. I am an Electrician bye trade, and we pull wire off of 1000 ft spools that are mounted to "carts" and into residential buildings to wire new construction. I think this cart idea would be easy, and affordable for ya as well as very effective. Ok, so you build a ramp of sorts, onto the side ofyour trailer beside your tower that's wide enough for a large wheeled hand truck. You purchase 3 HF hand trucks, the ones with the npeumatic wheels, and put 2 bags of cement on each one, or their abouts... Whatever you can put on without hurting yourself. on the back ( the handle side) weld 2 pegs, sticking out about 2", one on each side of the handle at 90 degrees to the back of the handtruck. All you do, is wheel these 3 carts off your trailer, no lifting involved, and set them down at a set distance, at the correct angles with the handles on the ground, rotated around the wheels so it's easy to maneuver, untill the pegs dig into the ground a bit. The guy wire should be attached at the "bottom" of the hand truck, as if there is enough leverage i.e. wind to start to lift it at all, it will force the 2 pins to dig in more. If you tied the guys to the handle side facing the antenna, if it were pulled enough, it would pull the pins out of the ground, and then it might want to wheel around on its own Anyway, this is my thought on it. Those handtrucks can be had pretty darn cheep at HF when they have they're 50% off sales and what not. Brian Lee Sparkeee27 Good Job, and Keep it up!

  10. #10
    Join Date
    Jul 2005
    Location
    California
    Posts
    630
    We took the tower out to the Black Rock Desert for FD2005. The weather was pretty unseasonable for a weekend in June. We got hit by several storm fronts and suffered gusts that were up to probably 50-60mph, possibly more. During the course of the storms, we intentionall chose to leave the tower fully extended and unguyed to see how well it would weather the storm. We had a full-size five element 20M beam on top that represented a very significant wind load.

    During the storm, the only movement that I noticed was the upper sections of the tower moving around in the lower section. The sections telescope and there's enough tolerance between sections to allow a little movement when they're fully extended. I never once saw the base section or the tower start to tilt during a heavy gust.

    With all that said, I'm still going to add some outriggers to make it more stable. I think I'm also going to tie some rope to the top of the fully extended tower and see exactly how much force is required to make it start to tilt. The plan next year is to add a long mast and have a full-size 40M two element beam on top of the 20M beam.
    -Heath

  11. #11
    Join Date
    Jun 2005
    Location
    Newton,NC
    Posts
    30
    gives me some ideas.


    James (KF4TEA)
    Sometimes, we just need to remember what the rules of life really are: You only need two tools: WD-40 and Duct Tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement