We used one for the Parker County ARC field day event and I can tell you it
was really neat to work with.
All it took was two very small motors and a couple of winches for what we had
to work with and mounted to it up went the three
element tribander.
Here is a pic or two of the event:
http://www.qsl.net/w5pc/fieldday2005.htm
73 fer nw,
Bob AD5VJ(AAR6VM)
http://www.ad5vj.com/
Member CTDXCC
10X# 37210, FP#-1141
SMIRK#-5177, RARS #-149
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Lux
> Sent: Monday, June 26, 2006 3:42 PM
> To: Kelly Johnson; towertalk@contesting.com
> Subject: Re: [TowerTalk] Building a Tower Trailer
>
> At 12:32 PM 6/26/2006, Kelly Johnson wrote:
> >I would like to mount a Force12 LPT tower on a trailer. Anyone have
> >any experience building a trailer for a tower (or otherwise)? I am
> >looking for design/construction tips. In particular, I need
> a trailer
> >that is small and reasonably inexpensive. In particular, I
> would like
> >the trailer to be as narrow as possible yet still stable enough for
> >towing. I'm thinking something with retractable/removable struts.
>
> We have a couple tower trailers we've used for FD ops at the
> JPLARC/CITARC operation. Both were essentially homegrown..
>
> Here's some comments, for what they are worth..
>
> Consider using a hydraulic ram to push the tower vertical.
> By the time you fool with pulleys, lift arms, winches, etc.,
> you'll wish for the simplicity of hydraulics. You can use
> inexpensive ag cylinders/rams (about $100 each, brand new)
> like they use on tractors, and a small electric motor driven
> pump. Look at the gear sold to put snowplow blades on pickup
> trucks, for instance.
>
> Big advantage of hydraulics: you can limit the speed it
> moves: in both directions. No sudden, whoops there it goes
> over the balance point.
>
> If you have a crankup style tower, you can get a hydraulic
> motor to run the winch. Hydraulics are wonderful this way..
> by selecting the different displacements in the pump/motor,
> you essentially get gearing for free.
>
> The CITARC trailer has a boat winch type hoisting apparatus, and it's
> *exciting* every time the mast goes up and down, for a whole
> raft of reasons.
>
>
> You WILL need outriggers to make it stable in any sort of
> wind. You can
> make them telescoped (we have a series of 4' nested sections
> of square
> steel tubing, but it takes a while to unnest, put them into
> the sockets,
> drop the pins, etc. And then you still have to fool around
> with jacking
> and tensioning them appropriately. Some sort of hinge
> arrangement seems a
> good idea, and isn't much more complex to build, IF you have
> someone around
> to do the welding..
>
> Even with outriggers, odds are you'll need temporary guying
> anyway, so, do
> some analysis and don't make your outriggers bigger than they
> need to be.
>
>
> Find a good welder to work with.
>
> Make sure the CG of the system is low when the mast is in the stowed
> position. W4EF can tell you some hair raising stories about the
> instability of the CITARC trailer on the freeway, largely due to
> underdamping of a high CG (the tower sits a good 6 feet off
> the ground in
> the horizontal position) interacting with the tow vehicle and the
> aerodynamic forces (which are considerable at 60 mi/hr).
>
> You need some sort of positive lock to hold the tower in place after
> erection. The lock should not involve reaching into somewhere
> to insert a
> pin in a close tolerance hole.
>
> Assume that the tower WILL get bent sooner or later, and
> you're still going
> to need to get it retracted and stowed.
>
> You need some big "footpad" plates to spread the loads of
> your jacks and
> outriggers. You need somewhere to store those plates on the
> trailer, where
> they're not buried under tons of stuff. Think about the sequence of
> stopping, pull the plates out, run down the jacks, unhook the
> tow vehicle,
> deploy the outriggers, etc.
>
>
>
> Consider storage of stuff on the trailer. You need a way to
> secure it to
> the trailer so it a)doesn't fall off when towing and b)
> doesn't get stolen
> off the trailer when it's stored/parked/unattended. It's
> also nice if you
> don't always have to be reaching down into bins or climbing up on the
> trailer to get at stuff.
>
> It's definitely worth looking at what grips/gaffers in the
> movie business
> use. They spend a lot of time and energy lugging heavy stuff
> around on
> locations. Check out things like "taco carts" and "cable
> dollies". The
> former are nifty rolling carts with slots/cubbies that
> exactly fit standard
> plastic tote bins, and a bar across the front to hold them in.
>
> Consider where your generator(s) are going to be located on
> the trailer,
> and that they can be run with the tower up or down (or, for
> that matter,
> providing power to move the tower). Power distro panels are also
> nice. Cable trays and guides keep you from severing that coax at an
> inopportune time.
>
>
> >My LPT1242 worked out extremely well for FD this past weekend. I'm
> >hoping to make it even more convenient by mounting it on a trailer.
> >Unfortunately, I have limited space at my home for a trailer and thus
> >need it to be small, narrow, and light enough that I can
> push it along
> >the side of my house into the back yard.
> >
> >Any advice would be appreciated.
> >_______________________________________________
> >
> >
> >
> >_______________________________________________
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> >TowerTalk@contesting.com
> >http://lists.contesting.com/mailman/listinfo/towertalk
>
>
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