[TowerTalk] Building a Tower Trailer

Mark Beckwith n5ot at n5ot.com
Tue Jun 27 11:26:50 EDT 2006

>I would like to mount a Force12 LPT tower on a trailer.

Wow, a tower trailer thread.  Few things turn me on more in our great hobby 
than tower trailers.  This will be long.

I read and digested the whole thread and here's my $0.02.  All of us owe a 
debt of gratitude to Wayne Overbeck (N6NB, formerly K6YNB, aka "Mr. Cabover 
Kilowatt", etc) for his pioneering work in applying mobile towers to amateur 
radio.  I guess we should assume Wayne is not reading this or he would have 
chimed in long before now.  Wayne started with a small crankup tower mounted 
to a camper, and set the world on fire by taking a full power contest 
station with real antennas mobile to a rare location, thereby paving the 
road to victory.  Not satisfied with that small tower, Wayne hand-built 
several more tower trailers based on the ones available commercially from 
Tri-Ex but made of "Triexium" which is really another name for "Unobtanium" 
and they were priced accordingly.  Hence, hams have been building their own 
tower trailers ever since.  Wayne looked at the Tri-Ex ones and somewhat 
duplicated them.

With very due respect to Jim Lux, Jim and I have both had the pleasure of 
using Wayne's trailers, and I will offer a slightly different perspective 
from Jim.  I know Kelly's original question is about something relatively 
small.  It must be noted, however, that before the Cellular industry was 
even imagined, Wayne had mounted a full-out motorized LM-470 on a tandem 
axle trailer, and built the thing out of structural steel at what we used to 
call "night school."  That's a big tower trailer.  Enough said.

There are two schools surfacing: Big is sometimes very necessary, but small 
can be very useful.  You won't put up a decent 40M contest antenna, which 
many of us in Southern California have done for many decades in many 
contests using Wayne's trailers, with a 30 foot tubular mast on a trailer 
small enough to fit by the house.  Obviously.  But the benefit of having a 
30 or 35 foot mast on a small trailer is HUGE.  Kelly's got the right idea. 
In fact, after Terry's post, I have started to look at those freeway 
construction light rigs in a new way :)

Jim was somewhat critical of Wayne's trailers (it should be noted that the 
trailer we have the most experience with I believe was built by Marty Woll, 
N6VI, alongside one just like it that Wayne was building at the same time - 
virtually identical - they built them together) but I point out that Wayne 
faithfully duplicated a commercially produced tower trailer, pretty much 
down to the inch.  Jim says the erection could be exciting (sorry) but after 
a few times you get used to it (sorry again).  I never thought it was much 
of a big deal.  The boat winch always seemed to work great.  Hydraulics 
would be cool, but in my opinion far more complicated.  These two trailers 
had Tri-Ex MW-65 4-section 65 foot crank up towers mounted to them.

Jim was critical of the CG issues, but in my opinion, they come with the 
territory.  You're holding over a thousand pounds of steel at about 7 feet 
above the ground, you're going to have CG issues.  I don't know the details 
of the "scary moments" alluded to, and I don't mean to imply that those guys 
are bad drivers, but I logged probably 2000 miles on those trailers in 14 
years, and I never felt uncomfortable towing them, not once.  I also never 
had to swerve to miss a deer, or had to drive with a hellacious cross-wind, 
which could well cause problems with such a payload.

Another reason Kelly's got the right idea keeping it small and light :)

The shorter the tower, the closer to the ground you can mount it, too, 
because it doesn't take as much vertical room to swing it up when in 
position.  I have one of those old 4-section 10-foot nested towers sitting 
around at N5OT - I am only waiting for the right combination of inspiration 
and materials - I already found an old single-axle boat trailer at a yard 
sale for $50.  Wherever you need a 40M contest antenna, you probably also 
need antennas on 20, 15 and 10, so those short/light supports have a 
significant role to play in any portable contest/emergency operation.

But so do the tall heavy ones, which I think is Wayne's point for building 
them.  I heard about the JPL/Caltech mishap where Marty's tower trailer went 
over and I was very sad - me an' that trailer were BUDS - but the good news 
is it's restored and back in service, thanks much to Jim and Mike's efforts 
(and a bunch of other dedicated club members from both institutions).  This 
is by way of saying Jim's caveat about wind is a MAJOR DEAL.  I wouldn't go 
as far as to say "assume it's going to get bent at some point" because with 
the right combination of rope guys and competent people you can get a 5 
element 20M yagi up to 65 feet on one of these.  I think the rope guys are 
mandatory, tho.  The outriggers are nice but they basically help with 
getting the tower vertical and the antennas on it.  Once you start cranking 
it up, you can get out of shape in the wind and have a very dangerous 
situation.  Rope guys can give you some control over it, in my opinion 
enough control to head-off a catastrophic outcome.

Don't be a fool and climb it when it's cranked up.  That's foolish enough 
when the crank-up's installed permanently in concrete, let alone on a mobile 

Oh my gosh, and get the tower vertical.  Really vertical.  Get it right.

Shouldn't have to say those things, but there you are.

So, tower trailers are every FD guy's dream - and those of us that's used 
'em, well, they are a dream come true.  They are very expensive to buy 
commercially, which is why most of the ones (all?) you see on ham operations 
have been home-made, so YMMV as they say.  Wayne built some great tall ones 
initially, and then even Wayne saw the logic in building some short ones - 
Dino posted those photos of one of Wayne's short ones - Thanks, Dino.

Can we get the Caltech/JPL guys to post a set of photos showing the trailers 
in use?  I think there are a number of TT readers who would enjoy seeing 

You all that are familiar with the stories I'm telling, forgive me if I 
didn't get all the details exactly right.  That's a lot of years and a lot 
of tower trailers on a lot of portable operations.

Back to the woodwork.

Mark, N5OT 

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