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RE: "Pipe tower" mounting for G5500 stack...



Hi Gang

  I had a 'pipe' tower for several years, with no problems. BUT here's a few
things I did to avoid them:

- I used thick wall pipe (2 in dia, plus walls 1/8 in thick). They were made
of alloy (much lighter than steel)

- I had three mounting brackets up the wall, all equally spaced - not of the
'normal' TV type, but home made from 'Dexion' the top and bottom ones had
large areas against the wall (to spread the load), and also each had about 7
bolts fastening them to the wall. (Each bracket had a cross peice about 3
feet across)

- The middle bracket was smaller, and was intended to prevent the pipes from
bending too much.

- When doing this previously I have used 'RawBolts', but this time I used a
chemical fastener (2 part and hardens in about 12 hours). It expensive, but
saves the stress on the bricks. Also my house has brickes when are, in
places, hollow, so raw bolts tended to crack the bricks when I did a few
test runs (on bricks that were spare, not ones already in the house !!)

- I mounted the AZ rotator about half way up the pole, and used a top
bearing arrangement. This kept the weight at the top of the pole a little
less than otherwise.

- I had a cross boom of about 7 feet with 2m and 70 cm crossed yagis and
each end.

- The whole thing was pivoted at the bottom, and tilted over via a block and
tackle arrangement between the top bracket and about two thirds up the mast.

- It worked fine for me !!

73

Jim, G3WGM


> -----Original Message-----
> From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org]On
> Behalf Of Robert Oler
> Sent: 20 September 2001 01:46
> To: equus@astro.as.utexas.edu; amsat-bb@AMSAT.Org
> Subject: Re: [amsat-bb] "Pipe tower" mounting for G5500 stack...
>
>
> Chris.
>
> I dont think that you want to try this.  Of course your milage
> may vary but
> I imagine that there are two bad things that will happen here
> based on what
> I have seen "others" do.
>
> One next door neighbor was/is a TV DXER so he wanted to do almost in
> windloading terms what you want to do.  HE found some drilling
> pipe coupled
> it together to give him 45 feet of which 20 feet were over the
> roof (second
> story house).  He bolted it at 2 foot intervals to his brick
> wall.  It did
> ok for about a year and then the semi tropical storm came by and the pipe
> came down and took substantial segments of his brick wall down with him
> (there is nothing really supporting the brick...in his case it wasnt
> structural.
>
> Another ham did something similar but he used "telescoping" TV
> antenna mast
> and guyed it after it got "high" except that of course he left
> enough on top
> for his antennas (two meter meteor scatter).  we had some modest
> winds (my
> weather station showed them at 20 gust to 32) and the whole thing set up
> some pretty funky oscillations as the guy's sort of danced a pretty
> interesting tune until it just sheared clean right on top of the guys.
>
> The loads have to go somewhere or they fatigue...
>
> Robert Oler WB5MZO Houston TX
>
>
>
> >From: Chris Wilkinson <equus@astro.as.utexas.edu>
> >To: amsat-bb@AMSAT.Org
> >Subject: [amsat-bb] "Pipe tower" mounting for G5500 stack...
> >Date: Wed, 19 Sep 2001 10:47:06 -0500 (CDT)
> >
> >Hey all,
> >
> >I'm working on putting a station on the air and am currently engaged in
> >trying to figure out the best way to mount my G5500 above the roofline. I
> >would like to utilize approximately 35' of pipe, the lower 18' of which
> >will
> >be bolted into a fairly solid brick wall.
> >
> >Chiefly, I am wondering what folks have used at their stations and how it
> >has fared. Obviously I can improvise, although I'd rather find out what
> >has worked for people currently in operation. The questions I
> have chiefly
> >involve the following:
> >
> >1. What type of piping and diameter are the safest and most reasonable to
> >utilize in this case? Obviously it needs to be strong enough to easily be
> >able to handle the wind load although not present a problem when
> it comes
> >to
> >mounting the G5500.
> >
> >2. What is the most secure method of bolting a "tower" to the side of a
> >brick building? Again, I can guess what would probably work, but
> if anyone
> >has firm ideas that would be appreciated.
> >
> >If anyone can let me know what has worked for them, I'd really appreciate
> >it. Pictures on the web would be appreciated!
> >
> >Thanks and 73's!
> >Chris // N8DVM
> >
> >----
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>
>
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