[TowerTalk] [Bulk] Fwd: those 4 foot 1.5" fiberglass army surplus tubes...

[Grant Saviers]

Several things to consider:

1. the mil surplus poles have a poor strength to weight ratio even if 
you solve the weak coupler problem.  Laid up fiberglass tubing is the 
way to go.
2. no matter the material, the wind load of the spider will be very 
high, probably more than the tower can handle
3. perhaps a top loaded vertical design would work, but then how will 
that interact with the C31XR's?  There are several of these in various 
antenna books.
4. if you can have pole supports far from the tower for the far end 
support ropes than #3 might work with some coil loading
5. most reports of towers inside 4 squares aren't good, see the topband 
reflector for some threads, detuning the tower is a must
6. perhaps a simpler tower plus reflector wire might be possible
7. a vertically polarized delta loop held off the tower at the top is 
something else to consider, run some EZNEC models.  I tried many models 
for phasing two on a 89' crank up but it was a no go.

Check the antenna books and do some modeling, low angle gain on 80m is 
not easy,

Grant KZ1W

On 12/26/2015 19:29 PM, Hans Hammarquist via TowerTalk wrote:
> Hi Tom,
>
>
> The tube itself is pretty sturdy but the is a huge problem to connect them with each other. They, at least the once I have, come with some silly collar that makes it seems as they can be connected together. Yes, they connect together but the collar does not have nearly the strength as the tube itself.
>
>
> I think they were intended to be used as tent poles, not too many connected together, maybe 3 - 5 pieces tops, and placed vertically.
>
>
> I have no experience with the tubes shattering but I have had several collars breaking. I once, and only once, manage to raise a 40 foot pole consisting of these tubes. It was at two places attached guy ropes and a falling derrick approach. (If I remember it right I used 13 tubes at the time.) Next time I tried, I wasn't successful.
>
>
> I doubt that you can use them for a long, vertical member unless you find a way to "weld" them together. I guess a better approach is to "bit the bullet" and buy one of the "more established' fiberglass poles.
>
>
> Let us know your approach.
>
>
> Best 73 and good luck de,
>
>
> Hans - N2JFS
>
>
>
> -----Original Message-----
> From: Tom_N2SR via TowerTalk <towertalk at contesting.com>
> To: towertalk <towertalk at contesting.com>
> Sent: Sat, Dec 26, 2015 4:26 pm
> Subject: [TowerTalk] those 4 foot 1.5" fiberglass army surplus tubes...
>
> You see them all over the place: ebay, even Dayton.  I'm looking to try and use several/many of them to create a horizontal "outrigger" or "boom"  to keep an eventual 80m 4 square away from a C31XR that is at 40 feet.  Unfortunately, that out rigger needs to be over 50 feet feet long, in order to clear the C31XR.   There will be two of them, hence 4 directions.  I know that I will have to create a boom truss to support it and the weight of the wire verticals, the coax and balun.  The question is, is there a better way?   I've looked at DX Engineering's fiberglass tubing.  I've looked at Max Gain Systems (?) fiberglass tubing.   I know that Vibroplex sells Spiderbeam fiberglass poles.  Everything I look at seems to be for use in the vertical plane, not horizontal.  So, any ideas?   If I use those 4 foot surplus tubes, how to connect them together - permanently?   I was thinking of epoxying them together and also use 2 stainless steel bolts in opposing directions.  Will they st
>   and up to UV or do I have to use Scotch 88 tape and protect them?  My initial thoughts are to mount a pulley at each end of the tube, and use that point as one of the connection points for the "boom truss."  I realize that I might even need multiple trusses along the "boom" to support it.  Thoughts?  Other ideas?   The tower is 90 feet, with a C31XR at 80 feet, so I can't just move the vertical up to clear the low antenna.  The turning radius of a C31XR is around 24 feet, so I don't have to go 32 feet out from the tower.   Thanks.Tom, N2SR______________________________________________________________________________________________TowerTalk mailing listTowerTalk at contesting.comhttp://lists.contesting.com/mailman/listinfo/towertalk
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