On 8/30/2011 9:14 AM, Jim Lux wrote:
> On 8/30/11 3:51 AM, Tom Kennedy wrote:
>> On any tower of any description a yearly maintenance check is a must, no
>> matter which system is being used. Towers that fail have been left with out
>> said.
Maybe so and maybe not. Ice storms have take down perfectly good tower
systems. So have high winds that were outside the norm for an area.
>
> You know.. we see this advice all the time: "It's time for your annual
> spring tower check".. but I wonder.
I see it as a good idea but it gives no guarantee.
And...how does the typical ham check a tower regularly. Remember that
every time you check the torque on bolts it tightens them just a tiny
bit more and if they have never seize on them the listed torque is going
to be way too much.
Guy line tension? that looks/feels about right, or a Loos gauge?
Elevated guy anchors Vs the standard approach?
is the tower still straight?
I typically give it a good once over every couple of years and check the
guy tension by feel. If I find one that is obviously under tensioned or
the guy anchor post shows a definite lean (elevated guy anchors that
weigh 17,000# each) THEN I get out the Loos gauge.
> There's an awful lot of power/telephone poles out there that I doubt get
> checked on an annual basis, and not a whole lot of them fail. Likewise
> light poles, freeway signs. Sure, if one breaks or gets obviously
> damaged, they go out and fix it, but is there some sort of organized "go
> check the poles and signs" activity?
Now days? With money in short supply it took several years (more like
two decades) to get them to clear the right-of-way for the power line
through the woods. It's a mile run across the section to the sub station
and it's woods all the way. In general they do a cursory inspection. IE
if nothing is obviously broken they don't touch it. BTW 5 years after
they cleared the right-of-way it's over grown to the point you can
hardly tell they ever cut it back.
>
> And on big transmitting towers, I can see regular maintenance being part
> of the plan (you have to paint the darn thing and keep the lights
> working, for instance).
And you can often pop the paint off the rust underneath. Comforting
thought at three or four hundred feet plus. <:-))
Plain steel wire rope guys an inch or more in diameter than ring like a
tuning fork when hit with a wrench. Boy, but those things can sing even
with that brown finish! <:-))
> Likewise, if you have a crankup.. moving mechanical devices need
> periodic checks.
Moving devices need to be moved periodically.
> Maybe it's because hams have a long history of improvisation and
> overloading (if the antenna didn't fall down in last winter's storms, it
> wasn't big enough) or it's from our agrarian heritage (the snow melts,
> time to get the plow out, curry the winter coat out of the draft horse,
> etc.)
>
> But, for instance, this thing about "checking the ground rod clamp"...
> the whole point of the clamp design is so that it shouldn't loosen with
> thermal cycling (i.e. does the electric company come out and check your
> grounding connection every year? Do you see recommendations that
> homeowners hire a licensed electrician annually?) And of course, one of
> the advantages of exothermic welding over clamps is that there's no
> possibility of it changing. Or is this, again, because hams have used
> all manner of improvised clamping schemes, and "design for immovability"
> wasn't necessarily in the list of requirements.
I think "We may want to move that in a year or so" is the most likely
criteria although those split clamps are about a third the cost of "one
shots" might be the over riding criteria. <:-))
73
Roger (K8RI)
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|