Jim, you are right, the Spiderbeam web site does not say not to drill a hole
in the pole.
Until now we thought people were smart enough not to do that.
AND nowhere does it say on our web that you can take our 40' pole, drill a
hole very near the bottom, insert a 15' aluminum mast just a few inches
inside of it and erect it like that. You did it on your own and broke the
pole.
A simple email could have prevented that. You know where to find me.
These poles were not built to be used like that.
They were built to give maximum height for verticals while maintaining
relatively low weight. We have lots of photos of customer installations on
our web site as well as our own and none show people using them on top of
other masts.
Maybe we should be more explicit but I find it very unfair of you to trash
our good products when the conversation is about using our pole for the
purpose it was designed for.
In fact I find your experience a great learning exercise on HOW NOT TO DO
IT.
If you want to place it on top of another mast, you must have a longer
insertion into the Spiderpole to spread the load.
I can show you how to do it for about $5 and then it won't break. But you
didn't ask.
As Jim Allen just pointed out, there are differences in different pole types
and like always, it's horses for courses.
When I go on a SOTA outing, I use a competitor's pole because it weighs just
half as much as mine.
But I have also broken that make of pole several times in the past.
I have never broken a Spiderbeam pole.
I have a lot of experience using fiberglass poles.
I've probably done at least 200 installations with them.
I have learned from my experience and the experience of handling customer
service on these poles for 8 years.
I maintain a web site where I share this information for free.
You can break anything if you don't use it for what it was intended for.
We have customers who ask us to make the poles lighter and others who ask to
make them stronger.
You can't have it both ways.
We have defined our niche as building tall lightweight poles.
For some installations, these may not be the best choice.
For others they are definitely the best choice.
I didn't say our poles do not break. Everything will break under the right
circumstances.
But when used for the purpose they were intended, ground mounted support for
tall verticals or supports for horizontal antennas (at reduced heights),
they are the best thing going for the price.
If I weren't so busy right now launching new products, I would take the time
to search out the major DX peditions we supported last year. Last time I
did it was about 3 years ago and it tallied about 20. We also sponsor tens
of smaller expeditions each year. You can't find a DX-pedition by any team
originating from Europe that isn't using Spiderbeam poles.
Mike (StepIR) also sponsors a lot of DX-peditions and the US expeditions
often take his beams and Big Step vertical. So you don't see or stuff used
as often by the US expeditions. However with the rising cost of air
transportation, I think you will see a migration. Just yesterday a N6
called me on the phone to order 4 or our 85' poles to be shipped to an
island off the coast of Africa.
I see every order for poles placed in Europe or the states and I see how
often someone orders spare parts for broken poles. When I compare these two
numbers, I can only describe it as very rare.
However when I see how some of the guys on expeditions raise poles,
including our own, it surprises me that they don't break more often. These
poles should be telescoped up in a vertical position, not pivoted up from
the horizontal to the vertical. Most hams don't know that because the ARRL
hasn't printed much on how to use fiberglass poles. As a result a lot of
good poles get broken by people doing stupid things. I offered to write an
article for QST on how to work with fiberglass poles but it was rejected due
to me being a supplier of poles. I understand their reasoning but that was
5 years ago and they still have not done anything on this topic.
Jim, the material on your web site is some of the most valuable information
on the web (for hams).
I have learned a lot from it and I send people there all the time.
But you might want to take a look at mine if you continue working with
fiberglass poles.
Cheers!
73 - Rick, DJ0IP
(Nr. Frankfurt, Germany)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Sunday, November 06, 2016 5:52 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] Fiberglass poles?
Two points. First, NOWHERE was it stated that a hole should not be drilled
in the pole.
Second, the website stated that "These are extremely strong poles, with a
much greater wall thickness (up to 2mm!) than the usual "fishing rod"
types. A special reinforcing winding technique - several layers of
fiberglass are wound in alternating direction (criss/cross winding) -
provides greatly increased lateral and linear strength."
Glen, W6GJB, is a mechanical and aeronautical engineer recently retired from
the space program, and is an expert in the strength of materials, how those
materials are formulated, and how they are used. Glen is the inventor of the
Air Beam Tents used by the VK0EK DXpedition. They are rapid deployment
tents, and were designed for use by the military.
Another area of Glen's expertise is parachutes -- he's one of the guys who
knows how to catch stuff returning from space. Glen carefully studied the
pole after it broke and found that it was NOT constructed as described
above, that there were not "criss/cross windings." If there had been, the
pole would not have broken because the hole would not have weakened it. He
measured the pole thickness as 1.75 mm.
As to the poles on DXpeditions -- within the last year, I attended a
presentation by a major DXpedition who had used these poles, and saw
photographs that clearly showed that the poles had broken in the wind.
73, Jim K9YC
On Sun,11/6/2016 1:06 AM, rick@dj0ip.de wrote:
> Jim broke the cardinal rule when he erected the antenna:
> He drilled a hole near the bottom of the pole and it broke at the hole.
> NEVER DRILL A HOLE in these poles.
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