Whoops, I hit the wrong button an sent my message prematurely. I'll try
again:
Hey Tom,
I have rebuilt a few military mast systems that are similar to what you want
to build. The two that I am familiar with are the AB-903/G and AB-1386/U
systems:
http://www.willburt.com/milQeamMast.asp
The AB-1386/U is 33 ft. It is made of five aluminum sections of diameters
4, 3.5, 3, 2.5 and 2 inches. Each section is about 7 ft 6 in long, so each
overlaps by about 1-1/2ft. The aluminum is T6-6061 grade structural with
0.065" wall thickness. I have had no problem with about 30lbs and 5 s
After totally rebuilding a few of these I think a mast of equal function
could be built pretty easily. You would need a flange with a pulley at the
top of the first four sections. At the base of the top four sections you
will need a shim made of self lubricating plastic to allow each section to
slide past each other in a snug but smooth way PVC?. Then a cable and winch
will allow you to erect it.
In getting a hold of the aluminum here is what I found: Most manufactures
will supply 12ft large diameter aluminum sections at a good price. For this
reason it may be worth while to consider a design using 6 ft sections if you
want to make more than one mast. Cut-to-length sections (such as 7'6") will
be more expensive. With some work I was able to find a replacement 7'6" x
4" x 0.065" section for about $130 shipped. For all five sections I think
that it would have been about $300 - $400.
This should give you some ideas.
If you would like some pics I can email them.
All the best,
Anthony
NR9R
On Fri, Mar 7, 2008 at 8:27 PM, Tom Sneden, K6VCR <k6vcr@cox.net> wrote:
>
>
>
> OK, I see that there might be some interest in receiver hitch type masts.
> I have been working out a design for a tubular tower that will attach to a
> receiver hitch.
> My goals are that it nest at about 10ft, extend to at least 35ft, be
> rotatable from the bottom, tilt over (in the 10 ft collapsed position)
> with
> a winch, extend using a winch and not weigh over 350 pounds.
> Basically a miniature version of an MA-40 with the rotating fixture.
> It is do-able and I think the price point will be in the neighborhood of
> $600.00 for parts.
> I lack formal engineering education and would appreciate knowledgeable
> opinions regarding wall thickness and type of aluminum tubing to use for
> the
> mast.
> This thread has really opened my eyes to height issues and would like to
> discuss the optimal vs. practical height issue as well.
> Tubing is available in varying wall thicknesses and they need at least
> 3/16"
> clearance between ID of outer tube vs. OD of inner tube.
>
> Before I ramble any further, would anyone else be interested in this
> thread?
>
> Tom
> K6VCR
>
>
> -----Original Message-----
> From: vhfcontesting-bounces@contesting.com
> [mailto:vhfcontesting-bounces@contesting.com] On Behalf Of Dana Rawding
> Sent: Friday, March 07, 2008 1:06 PM
> To: VHF Contesting
> Subject: Re: [VHFcontesting] A question of altitude
>
> It was a Clark QTM telescoping mast. However it was only 15ft and had
> the hefty price of $750.
>
> I booked marked it myself as I though it would have been very cool to
> have for uwave hill topping.
> http://www.clarkmasts.com/qtm_masts.php
>
> Dana
> N1OFZ
>
> On Mar 7, 2008, at 3:22 PM, Nate Duehr wrote:
>
> > You guys are making me wish I'd spent the $700 (I didn't have) on that
> > pneumatic bumper mount mast -- some guy had it up on eBay a few weeks
> > ago. I think it went to 30'.
> >
> > Did anyone else see that and get tempted for their rover?
> >
> > LOL! Great fun THAT would be... I know I'd be out in the rain
> > trying to
> > pump the thing up, cussing it out while missing contacts... but I'd
> > come
> > home and rationalize it all away as "fun"!
> >
> > Heh heh... must be something wrong with us rovers... mentally. (GRIN)
> >
> > Nate WY0X
> > _______________________________________________
> > VHFcontesting mailing list
> > VHFcontesting@contesting.com
> > http://lists.contesting.com/mailman/listinfo/vhfcontesting
>
> _______________________________________________
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