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Message Digest
Volume 28 : Issue 131 : "text" Format
Messages in this Issue:
Re: CO backup power (was Re: FiOS in MDU Buildings
Re: Waveguide (was "size a major consideration...")
Re: Waveguide (was "size a major consideration...")
Re: CO backup power (was Re: FiOS in MDU Buildings
Re: CO backup power (was Re: FiOS in MDU Buildings
Re: CO backup power (was Re: FiOS in MDU Buildings)
Re: CO backup power (was Re: FiOS in MDU Buildings
Re: CO backup power (was Re: FiOS in MDU Buildings)
Re: CO backup power (was Re: FiOS in MDU Buildings)
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Date: Mon, 11 May 2009 11:44:02 -0500
From: Hudson Leighton <hudsonl@skypoint.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings
Message-ID: <hudsonl-981035.11440111052009@news.isp.giganews.com>
In article <pan.2009.05.11.07.22.47.867008@myrealbox.com>,
David Clayton <dcstar@myrealbox.com> wrote:
> On Sun, 10 May 2009 20:44:22 -0400, Who Me? wrote:
>
> <humor>
> And you can test their charge by dropping a set size piece of metal across
> the contacts - if the metal vaporises then they are fully charged! ;-)
> </humor>
Been there, done that, 1400 amp hour cell and a 6 inch Crescent wrench,
lucky for me, the wrench was dropped onto the posts, not slipped while
in use. Anyone need a spare movable jaw & 3/4s of a hanging ring?
-Hudson
***** Moderator's Note *****
OK, it's time for the annual retelling of the story of my Central
Office Technician Rating examination!
New England Telephone had a rating system for technicians: after about
five years of experience, techs could take an examination given by two
supervisors, to obtain "Rated" status. As a rated tech, you got first
pick of vacations, preference in tour assignments, and ~$50 additional
- 1980 money, mind you - in you paycheck every week. Trust me: it
wasn't for show, and you had to have a sponsor - another rated tech -
recommend you for the test and accompany you to the exam.
Part of the exam is on power room operations, usually a fairly short
section for all but Power techs: since I was in Toll, I only had to
study some basic fire safety and general rules.
Unfortunately, after an hour explaning duplex circuit operation and
the proper procedure to compensate for ground resistance in EMX-1 and
EMX-2 equipment (yes, I'm that old), my mind went totally blank, just
when one of the examiners asked me "Bill, what can you tell me about
tools used in the power room"?
I sat there, feeling like I could hear (pun intended) a pin drop, with
my mind's gears grinding. Instinct kicked in: I reached into my head's
gearbox and hit the BS Overdrive switch.
"Ah, OK, well, it would have to be a tool manufactured and approved
for use in an explosive atmosphere, under current inspection, and
properly maintained".
My sponsor kicked me under the table. I looked right at him. The
supervisors were holding their hands in front of their mouths, trying
not to laugh. Time stood still for a great many very long seconds.
... and my mental transmission finally caught, and I said "of course,
you need to make sure the handle is properly insulated", at which
point the supervisor guffawed, and asked me "How do you do that,
Bill"? I answered, "Well, ah, you can put tape on it".
They shook my hand, still laughing, and I was a made man.
Bill Horne
Temporary Moderator
------------------------------
Date: Mon, 11 May 2009 11:55:56 -0500
From: Neal McLain <nmclain@annsgarden.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Waveguide (was "size a major consideration...")
Message-ID: <4A08589C.70701@annsgarden.com>
Several recent posts in this thread have mentioned the "horn" microwave
antennas used by AT&T Long Lines. As David Lesher noted in TD 28:127:
> Those horns often carried six circuits: 4 Ghz horz
> polarization, 4 Ghz vertical, 6 Ghz h & v, 11 Ghz h & v. They
> delivered a jaw busting 48dB of gain at 11 Ghz, with a beam
> width of about 0.75 degrees. But then they had 36 ft^2 of
> throat, were 14 ft+ tall and weighed several thousand
> pounds... despite being aluminum...
Narrow bandwidth not only provided substantial main lobe gain, but it
reduced side lobe gain. This, in turn, reduced interference to or from
other antennas, including satellite antennas.
Cable TV companies sometimes used TVROs based on the same design in
order to block interference from point-to-point microwave links. Two
examples:
Lyndhurst, New Jersey, 1982:
http://annsgarden.com/telecom/Blocking/Lyndhurst_NJ.jpg
Lamar, Colorado, 2007:
http://annsgarden.com/telecom/Blocking/Lamar_CO-1.jpg
http://annsgarden.com/telecom/Blocking/Lamar_CO-2.jpg
Of course, in some situations, there was an easier way to block
interference: put the antennas behind a hill or a berm. Two examples:
West Haven, Utah, 2001:
http://annsgarden.com/telecom/Blocking/WestHaven_UT-1s.jpg
http://annsgarden.com/telecom/Blocking/WestHaven_UT-2s.jpg
Warwood, West Virginia, 2008:
http://annsgarden.com/telecom/Blocking/Warwood_WV.jpg
Neal McLain
------------------------------
Date: Tue, 12 May 2009 19:33:24 -0700
From: AES <siegman@stanford.edu>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Waveguide (was "size a major consideration...")
Message-ID: <siegman-F542E9.19325412052009@news.stanford.edu>
In article <4A08589C.70701@annsgarden.com>,
Neal McLain <nmclain@annsgarden.com> wrote:
>
> Narrow bandwidth not only provided substantial main lobe gain, but it
> reduced side lobe gain. This, in turn, reduced interference to or from
> other antennas, including satellite antennas.
>
Greatly reduced side lobe and especially back lobe gain was _the_
crucial feature of these antenna for the Penzias Wilson Nobel Prize
experiment. When you're trying to see 3 K microwave background
radiation in the main lobe point pointing vertically out into space,
having the side and back lobes picking up 300 K radiation from the
ground all around you can be a real problem.
***** Moderator's Note *****
Being a ham operator, you'd think I would know, but I'm ignorant of
the trade-offs and benefits of using the various types of microwave
antenna. If the readers can supply an "executive summary" that telecom
managers could use when considering microwave alternatives to leased
lines, I'd be happy to publish it.
Bill Horne
Temporary Moderator
------------------------------
Date: Mon, 11 May 2009 12:56:36 -0500
From: bonomi@host122.r-bonomi.com (Robert Bonomi)
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings
Message-ID: <X72dnbYXufBJ-5XXnZ2dnUVZ_radnZ2d@posted.nuvoxcommunications>
In article <2slNl.6854$Lr6.3076@flpi143.ffdc.sbc.com>,
Who Me? <hitchhiker@dont.panic> wrote:
>Julian Thomas wrote:
>> IIRC ESS1 (Morris Ill.) had minimal batteries, and a system that
>> was supposed to start the diesels within 1/3 sec
>> after a primary power failure.
>
> I think your memory is failing you. All the #1 ESS offices in
> Illinois that I visited/worked in ... which were a LOT, had battery
> power for about 4 hours and were routinely tested on batteries for
> an hour. Most had diesel generators that were manual start only.
Cripes, folks. The 1/3 second was the 'reaction time' for the genny
to _begin_ the start-up sequence. They were *NOT* producing stable
power after 1/3 second.
If the power was out for -less- than 20 cycles, the generators did not
[even] *try* to start.
Telco "backup" power configuration varied widely depending on the
situation at the particular C.O. -- how likely it was to have a 'more
than momentary' failure, duration of a 'typical' failure, etc. Also
taken into consideration was how long it would take to get a 'spare'
generator there, if required.
"Manned" C.O.s did tend to have primarily "operator-started"
generators -- i.e. somebody had to 'push the button' before it turned
over. ('policy' was to engage the generators ASAP after utility power
was confirmed 'down'.)
Hoever, "unmanned" offices did rely on "auto-start on power-fail"
generators. They did have several hours of battery run-time -- *but*
the generators kicked in 'immediately', so that the battery power
could be saved for 'last resort' use -- e.g. if the generator
_failed_, the C.O. could stay operational "for a while", while waiting
for "people" to arrive.
------------------------------
Date: Mon, 11 May 2009 18:51:52 +0000 (UTC)
From: David Lesher <wb8foz@panix.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings
Message-ID: <gu9s47$fm6$1@reader1.panix.com>
Sam Spade <sam@coldmail.com> writes:
> But, unlike an unattended central office, hopefully the operators will
> have brought the diesel generators on-line at a nuclear power plant
> while [implementing] a check-list that gets them running before they
> are actually required to be brought on-line.
By definition, emergency shutdowns are unplanned, unscheduled,
events. There are tight standards on the backup power for that reason.
I vaguely recall triple-redundancy; i.e. 3 large Diesels, where one of
the three can do the shutdown.
In telco ops; by history and design, everything runs from -48V. I've
seen KS-number fluorescent lamps, etc. I suspect there was a 48V soldering
iron somewhere. I believe the goal was the battery plant could keep
essential services up (without the generator working) long enough for a
truck-mounted unit to arrive.
In the early 1990's, I know of a CO feeding a large local ISP. Ma had
to run fiber in from a more distant CO to provide the expansion channel
banks needed -- She had run out of -48V capacity in the nearby one.
There was a great deal of back & forth testimony in the Maryland PSC case
about FIOS & other changes. One topic was how Ma pawns off the power
issue to the homeowner, and won't maintain the Battery Backup Unit.
All the CO generators in the world won't help you when you have no
local power.
------------------------------
Date: Mon, 11 May 2009 18:41:16 -0400
From: T <kd1s.nospam@cox.nospam.net>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings)
Message-ID: <MPG.24727398fadb75b9989a0f@reader.motzarella.org>
In article <gu7ucl$ecd$1@news.motzarella.org>, spfleck@citlink.net
says...
>
> > Memory fades over time, but I recall the basement filled
> > with the largest lead acid battery farm I'd ever seen. ...
>
> The biggest battery backup I've ever seen was in the early 1980's
> while taking a tour of a AT&T satellite feed [antenna] farm in
> Kimbles, PA near Lake Wallenpaupak. The dishes were more than huge.
Biggest one I ever saw was PaeTech's Providence, RI switch. They had a
6' high rack that had to be about 30 feet long and maybe 4' or 5' deep
of batteries for the 5ESS/2000 switch.
***** Moderator's Note *****
Real battery rooms cover the entire floor of the building, as did the
batteries for the panel exchange in use at Back Bay in Boston until
1972. They were Exide black monoliths, about 18 inches on a side, and
they could provide a busy-hour load in excess of 500 amps.
Every time I saw them, I half-expected to find an ape with a bone in his
hand and "Also Sprach Zarathustra" playing.
Bill Horne
Temporary Moderator
------------------------------
Date: Mon, 11 May 2009 18:39:14 -0400
From: T <kd1s.nospam@cox.nospam.net>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings
Message-ID: <MPG.2472731e20cfd36989a0e@reader.motzarella.org>
In article <100.7857030060d9044a.006@jt-mj.net>, jt@jt-mj.net says...
>
> On Wed, 6 May 2009 10:37:51 EDT Wesrock@aol.com wrote:
>
>
>> The traditional Central Office had a diesel generator in addition to
>> its batteries, so a few days is not a problem.
>
> IIRC ESS1 (Morris Ill.) had minimal batteries, and a system that was
> supposed to start the diesels within 1/3 sec after a primary power
> failure.
>
> I have no idea as to how that worked out or was modified.
Diesel is definitely not the way to go. I remember when we were doing
disaster scenarios the first thing to go would be transport of diesel
fuel.
Natural gas however would remain on for a slightly longer duration.
That's why we went with a natural gas fired 125kW generator for our
server and IT space.
------------------------------
Date: Tue, 12 May 2009 17:06:03 +0000 (UTC)
From: Paul <pssawyer@comcast.net.INVALID>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings)
Message-ID: <Xns9C0985974AC41Senex@85.214.105.209>
T <kd1s.nospam@cox.nospam.net> wrote in
news:MPG.2472731e20cfd36989a0e@reader.motzarella.org:
> In article <100.7857030060d9044a.006@jt-mj.net>, jt@jt-mj.net
> says...
>>
>> On Wed, 6 May 2009 10:37:51 EDT Wesrock@aol.com wrote:
>>
>>
>>> The traditional Central Office had a diesel generator in
>>> addition to its batteries, so a few days is not a problem.
>>
>> IIRC ESS1 (Morris Ill.) had minimal batteries, and a system that
>> was supposed to start the diesels within 1/3 sec after a primary
>> power failure.
>>
>> I have no idea as to how that worked out or was modified.
>
> Diesel is definitely not the way to go. I remember when we were
> doing disaster scenarios the first thing to go would be transport
> of diesel fuel.
Diesel fuel is widely available, can be stored easily on site, and
can be transported in portable cans (or even buckets) in an
emergency.
> Natural gas however would remain on for a slightly longer
> duration. That's why we went with a natural gas fired 125kW
> generator for our server and IT space.
When the gas main goes out, try getting a bucket of natural gas.
:)
--
Paul
------------------------------
Date: Tue, 12 May 2009 23:08:05 GMT
From: "Tony Toews \[MVP\]" <ttoews@telusplanet.net>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings)
Message-ID: <vuvj05tpriobp35iqgs36m2l105h3qq17t@4ax.com>
T <kd1s.nospam@cox.nospam.net> wrote:
> Diesel is definitely not the way to go. I remember when we were
> doing disaster scenarios the first thing to go would be transport of
> diesel fuel.
Diesel is exceedingly viable so long as you understand the risks.
Transport is definitely one of those risks which can be alleviated by
a larger storage tank.
Do note that the transfer pumps which move the diesel from the large
tanks to the closer small tanks should be on generator power and not
on utility power. Obvious now yes but this was mentioned a while back
in comp.risks.
> Natural gas however would remain on for a slightly longer duration.
> That's why we went with a natural gas fired 125kW generator for our
> server and IT space.
Not in earthquake country.
You'd also be surprised, or not, just how many gas stations and bulk
fuel dealers don't have generators. None that I know of. Maybe
Florida is in better shape as I heard the governor there decided to
put in a law along those lines given the number of hurricanes which
take out power for a while.
Note that the bulk fuel dealers have a lot of anti siphoning devices
to combat thieves. And likely legal liability issues if those thieves
manage to burn themselves up. So you pretty much have to go through
the pumps.
Tony
--
------------------------------
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