[TowerTalk] Building a Tower Trailer

[Jim Lux]

At 04:02 PM 6/26/2006, Kelly Johnson wrote:
>Outriggers would be preferable, but guys would be acceptable if necessary.
>
>Here's another thought.  Would it make things easier or harder to
>assume that the tower will be transported by an SUV or truck whereby
>the bed of the truck or the roof of the SUV could be used to hold the
>tower for transportation.  Remember, the whole goal here is to make it
>possible for me to transport and erect the tower by myself.


This is what I was contemplating with my 50 foot mast/flagpole hooked to 
the car roof rack idea. It's very doable (take a look at what the Kite 
Assisted Photographer/Pole Cam guys are doing).  Actually, this works even 
better than the tower trailer, because it gets your pivot point up high, so 
you can have your mast almost perfectly balanced.  Then, you can climb up 
on the roof to attach the antenna, once the mast is vertical.

Think of the rigs used to push a rowboat,scow, canoe, raft, kayak up on the 
roof rack. (the ones that don't require you to lift the boat up over your 
head)  A couple rollers and an extending member so that the pivot clears 
the rear (or side) of the car. You slide the tower back until about 6 ft is 
hanging over the pivot, tip it up, and you're done.  I've seen a clever 
design for sea kayaks and canoes that sort of moved diagonally, so that the 
hatch could still open.

The problem I've found is wind survival. You either have to be willing to 
tolerate a collapse in fairly moderate winds, OR, deal with the 
outrigger/guy/ballast issue.  The roof rack just isn't strong enough to 
take the side loads. {Lesson learned: Do NOT attach guy lines to the roof 
rack!, not only does the rack fail, but it also deforms the roof with it, 
which makes it expensive to fix.}  In any case, design so that a collapse 
destroys something cheap to fix, not your car.

W4EF has erected a 50 foot-ish mast for the 160 contests anchored to his 
truck several times. His comment is that you need to bear in mind the wind 
loads when tipping up.  With a crankup/telescoping tower this wouldn't be 
such a big deal. 
http://www.dellroy.com/W4EF's-Ham-Radio-Page/Salton-Sea-05/Salton-Sea.htm
http://www.dellroy.com/W4EF's-Ham-Radio-Page/Stew-Perry_El-Mirage/El-Mirage.htm