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I think it's fair to assign majority fault to installation
technique. However, since the cable bundle was not entirely torn
apart, I wonder if a slightly stronger cable would have remained
operational. I wonder if the water resisting tape would have
prevented corrosion and failure at the PoE injectors.<br>
<br>
There will always be sections of cable (eg: literal corner cases)
where it won't be possible for it to have steel above it. This is
where better equipment selection can keep us online longer.<br>
<br>
If you look at this through the economic lens, we have an abundance
of available dollars, but a shortage of available man-hours. The
unit cost increase isn't that great either. Our normal TC-Pro costs
are $150/box. The new CAT6 would be $200/box. Meanwhile we just
spent $50 of gas (for me alone), and time-value of me & Dale to
do the inspection visit. We haven't even paid the cost of
replacement visits yet. Who will be willing to climb the tower in
the winter? Who will be willing to do ground crew in the snow?<br>
<br>
If you look at this through a site reliability lens, since each
cable is a single point of failure, there isn't much else to be done
except maximize the cable's reliability. The modems cannot take 2
cables for redundancy. We also incur reputational damage every time
we have a reliability issue like this. That is harder to quantify
and regain.<br>
<br>
I agree with your point that all sites may not need this (eg:
Beacon, QueenAnne), but I was implicitly referring to our tower
sites.<br>
<br>
I also agree with your point about site inspections, and think we
should do them on a schedule, but that's a separate process
improvement to the stuff I wanted to focus on here.<br>
<br>
What makes this site susceptible to ice fall damage is fairly
constant high winds, moist air directly from the pacific, and the
fact that it's pretty tall (looks like 180ft?) which allows the ice
to build up a lot of speed before it hits.<br>
<br>
In my earlier UPS email I broadly stated I would like us to focus on
reliability in 2021. The power system improvements are direction
#1, better hardware and installation techniques are #2, regularity
of inspections #3, and monitoring / management software improvements
will be #4. These aren't in priority-order, just enumerated to keep
them distinct and delegatable.<br>
<br>
--Bart<br>
<br>
<br>
<div class="moz-cite-prefix">On 2/7/2021 1:24 PM, Rob Salsgiver
wrote:<br>
</div>
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<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I’m
not opposed to exploring better / tougher alternatives, but
I wonder how much is due to the quality of our previous
selections vs our installation experience and knowledge
level at some of these earlier sites. We’ve done pretty
well in most installations for several years now. If our
existing equipment selections are sufficient in most cases
as long as we incorporate lessons learned on installation
specs (under steel members, ice risks, etc), we may not need
to incur the added expense for every site going forward.
This is not a slam against anyone who’s done prior installs,
as we all continue to learn even today. It is what it is.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">That
said, having tougher alternatives already explored and
tested gives us a path if the above proves to be malarkey.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">On
future visits to existing sites we should have a little
added focus on photos/examination of the condition of our
existing installs and put them in file for the record to
keep track of how well things are doing over time at each
location. I think this is pretty normal when we go on site,
but this is an expensive example to reinforce the idea.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Is
there anything notable about this site that makes it worse
for ice fall risks? I suspect not as I’ve seen ice damage
examples on non-HamWAN equipment on almost every site visit,
but worth asking.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Cheers,<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Rob<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
PSDR [<a class="moz-txt-link-freetext" href="mailto:psdr-bounces@hamwan.org">mailto:psdr-bounces@hamwan.org</a>] <b>On Behalf Of </b>Bart
Kus<br>
<b>Sent:</b> Sunday, February 7, 2021 1:05 PM<br>
<b>To:</b> Puget Sound Data Ring<br>
<b>Subject:</b> [HamWAN PSDR] Capitol Peak cable system
failure<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hello,<br>
<br>
I recently noticed we had multiple modems offline at Capitol
Peak. Dale & I went to visit Capitol Peak a few days ago
to inspect the situation. This is what we found:<br>
<br>
<a href="https://photos.app.goo.gl/KXajGkDGLsW41dQz7"
moz-do-not-send="true">https://photos.app.goo.gl/KXajGkDGLsW41dQz7</a><br>
<br>
It's a little hard to see in the photos, but our cable bus has
been ripped off the tower. When examining the cabinet where
the cables terminate, I found the cables to be wet, and we
discovered water pooling in the bottom of the cabinet:<br>
<br>
<a href="https://photos.app.goo.gl/kWwAWs2FvA6ghhC28"
moz-do-not-send="true">https://photos.app.goo.gl/kWwAWs2FvA6ghhC28</a><br>
<br>
So not only are the cables dangling, they're also broken to
the point where we lost communications and are now taking on
water. This was likely caused by ice falling onto the cables,
since that bottom bundle was mounted in such a way that it was
protruding inside the tower, instead of being under the cover
of angle iron like the rest of the horizontal coax nearby.
It's hard to pin down exactly when this happened, but the data
I've seen points to Jan 23rd for S3 falling offline.<br>
<br>
There is another cable of ours that had its support removed
about 80ft up the tower. It feeds the BawFaw link. The
damage was again along a horizontal run, from the cable ladder
to the dish on the opposite side of the tower from the cable
ladder. We typically run these under the steel members, so
I'm not sure what the failure there was. I wasn't able to
take good pictures of the dangling cable.<br>
<br>
The whole bottom bundle is impacting on the edge of angle iron
whenever the wind blows. This has likely cut through the
cables, although poor weather didn't allow close visual
inspection.<br>
<br>
I think this situation calls for some engineering changes in
addressing this and other future deploys:<br>
<br>
1) All horizontal runs must be protected from falling ice, by
having steel members above them.<br>
2) We should evaluate the use of tougher cable that is more
resistant to physical damage.<br>
3) We should evaluate the use of cable that is water-resistant
when it does get breached.<br>
4) We should evaluate the use of drip-loops (removing a
section of jacket) before the cable reaches expensive
equipment.<br>
5) We should measure the forces required to remove beam clamps
and establish minimum torque requirements.<br>
6) A camera system may have spotted these cable failures
before we experienced communication outages. Deployment has
been approved.<br>
<br>
There is some good info on addressing (3) on this page, thanks
to Dale's research:<br>
<br>
<a
href="https://www.truecable.com/blogs/cable-academy/into-the-great-outdoors-running-ethernet-cable-outside"
moz-do-not-send="true">https://www.truecable.com/blogs/cable-academy/into-the-great-outdoors-running-ethernet-cable-outside</a><br>
<br>
To address (2) I think we can look at stepping up to CAT6,
which is AWG23 instead of AWG24, and has a larger outer
diameter. The presence of a spline will also make the cable
stronger.<br>
<br>
This leaves us with a cushion problem, since our cushions are
only designed for 1/4" cable and CAT6 is thicker than that.
It seems we have gotten exceedingly lucky here! Valmont has
just recently released a new cushion design that accepts 7
runs of 4mm-9mm cable! The part # is BCU158M7.<br>
<br>
<img id="_x0000_i1025"
src="cid:part4.B733B424.0E153231@bartk.us" class=""
width="500" height="500" border="0"><br>
<br>
We also need to make sure these new cable selections will be
compatible with our current-spec EZ-RJ45 ends.<br>
<br>
I'm going to send a separate VOTE email to approve the
purchasing of samples of this new hardware, so I can verify it
will all work together. Let's use this thread to discuss the
problems, and if anyone has other/better solutions please
share here.<br>
<br>
--Bart<o:p></o:p></p>
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