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Chat => Tech Chat => Topic started by: UncleUB on August 31, 2012, 02:05:45 PM

Title: Power Cut
Post by: UncleUB on August 31, 2012, 02:05:45 PM

We had a power cut which started at 5.30 this morning.I thought I would find the number of our electric company and give them a call to see what was happening.
I went to look up their number via my smart phone and found I had no 3G data connection  :o.....How does that happen,is it something to do with masts/transmitters being out of action?

The power came back on about an hour later and my phones 3G was fine.

Title: Re: Power Cut
Post by: burakkucat on August 31, 2012, 02:17:38 PM

Quote

. . . I had no 3G data connection  :o.....How does that happen,is it something to do with masts/transmitters being out of action?

I would imagine so, yes.

It's only when the modern technology fails that we appreciate a copper (or aluminium) loop back to an exchange building which is energised by a battery of SLA cells to 50V DC.  :)

Title: Re: Power Cut
Post by: roseway on August 31, 2012, 03:34:14 PM

I agree with that. I always keep a good old steam phone handy, to use in the event of power cuts.

Title: Re: Power Cut
Post by: UncleUB on August 31, 2012, 04:15:33 PM

I see, thanks  :)

Just to add,I was able to send texts and make calls.

Title: Re: Power Cut
Post by: c6em on August 31, 2012, 05:43:09 PM

Perhaps the mast has its own backup power supply/generator but when in operation due to a power cut services available from the mast are reduced to "essential services only" to reduce power requirements from the backup unit.
If so this may reduce the cost of the backup unit considerably bearing in mind it will hardly ever operates and I can see that it might not make sense economically to give it a backup unit capable of running the mast at 100% power.

The issue of how long backups (battery etc) will operate for is going to get interesting once FTTC becomes widespread and indeed once voice phone over fibre starts to be installed -which needs a mains supply to work at the customer's end.

Title: Re: Power Cut
Post by: Ezzer on August 31, 2012, 07:10:58 PM

When a generator in an exchange starts up it can give you quite a start. I was in a village exchange waiting out a thunderstorm. The power for the village was knocked out.

It was a very small building, the generator filling one side of the floor with the telecoms on the otherside.

I was sat in the small gap between the generator and the desk. When that thing fired up ! I think the marks left by my fingernails are still in the ceiling.

Another occasion I was digging out a hydralic lifter to get at a joint in a carrageway. The lifter had been stored right under the air intake of the generator. Dont know what hurt more, my head hitting the intake or my ankle when I dropped the part I was getting.

The generators started on a regular basis, either to keep them running, or in the case of an actual power cut, which is supprisingly more common that I originaly thought, particuarly in times of storms.

Title: Re: Power Cut
Post by: Black Sheep on August 31, 2012, 08:08:44 PM

Quote from: Ezzer on August 31, 2012, 07:10:58 PM

When a generator in an exchange starts up it can give you quite a start. I was in a village exchange waiting out a thunderstorm. The power for the village was knocked out.

It was a very small building, the generator filling one side of the floor with the telecoms on the otherside.

I was sat in the small gap between the generator and the desk. When that thing fired up ! I think the marks left by my fingernails are still in the ceiling.

Another occasion I was digging out a hydralic lifter to get at a joint in a carrageway. The lifter had been stored right under the air intake of the generator. Dont know what hurt more, my head hitting the intake or my ankle when I dropped the part I was getting.

The generators started on a regular basis, either to keep them running, or in the case of an actual power cut, which is supprisingly more common that I originaly thought, particuarly in times of storms.

That was my job when I first started on BT. I was a 'Power Engineer', and 'Routining' the Genny was common-practice. It served two purposes really, 1) That the SLA's would carry the load whilst the Genny got to full running speed b) That the Genny could supply the required load to 'Essential services' only.

The 12-monthly routine was the worst, as we had to leave the Genny running for hours, rather than minutes and we had to constantly take various readings and jotting them down in the 'Log book'. Even wearing ear-muffs, the noise was awful. Also, we had to do an oil change and no matter how careful you were, you still ended up covered in the stuff and itched for days after.

Just for info purposes, all our local Exchanges have just undergone a major upgrade of Genny's, as the 'Essential' loading has increased quite dramatically due to LLU equipment.



 

Title: Re: Power Cut
Post by: Ezzer on August 31, 2012, 08:50:03 PM

Didnt envy that job, all of those were very loud  ??? Louder than a truck.

Mind you, you may have your moble service here in the states. Some may assume things telecom wise are better here, wrong assumption.

Today I barely have any signal for more than a couple of mins each hour. The delay before speech is transmitted is awfull, and it seems the same on any network. The quality of sound seems worse too.

Title: Re: Power Cut
Post by: asbokid on August 31, 2012, 09:07:55 PM

Quote from: UncleUB on August 31, 2012, 04:15:33 PM

Just to add,I was able to send texts and make calls.

Since voice and texts were still okay, it's perhaps just a coincidence that the 3G data connection failed at the same time as the power outage at your home.

The data and voice is multiplexed over the same point-to-point microwave backhaul links. So if voice is up, then data should be up, too.

Here are some photos of a cell tower. This "macrocell" mast is one of the highest in the country, covering one of the widest areas. Maybe 300 square kilometres.

On the very top of the tower are the sector panel antennae - our cellphones connect via these. Beneath are parabolic dishes for the backhaul network.  Both voice calls and subscriber data services are trunked via those microwave links before being switched onto the fixed wire network.

This particular mast is shared by several carriers who use it for GSM (900MHz and 1800MHz) and UMTS ("3G") on 2100MHz.  Power is supplied by the 25KVA transformer shown to the right.  The transmitter huts are air-conditioned. Not sure what power redundancy there is.

The capacity of the microwave point-to-points are probably in the order of 100s of Mbps.  If the map-reading is correct, the largest dish forms a point-to-point link of 20km.The towers are also used as relays for backhaul traffic from other cells.

cheers, a

(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww3.picturepush.com%2Fphoto%2Fa%2F9126771%2F480%2Fcell-mast%2FDSC-0726.jpg&hash=279d0bec7afa3eca72bdd52dab51e1ae4774e9d4) (http://picturepush.com/public/9126771)

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Title: Re: Power Cut
Post by: sevenlayermuddle on August 31, 2012, 11:06:06 PM

If the power outage was widespread, there is also the possibility that the cellular network was in some overload with all of the 'help' calls being made, and that it disabled 3G data as a defensive measure to preserve it's own bandwidth.


Up until a few years ago that scenario would have been unlikely as not many people would actually have noticed, or even cared about, an power cut at 5:30am in August.  But recently British Gas, in order to line the pockets of senior management save the planet , have been rolling out smart meters that, among other duties I understand, use the mobile phone network to 'phone home' when problems arise. 

In the almost unthinkable circumstance that that that pillar of society, British Gas, may not have thought this through, I wonder if it might result in network overload whenever a power outage arises?

Title: Re: Power Cut
Post by: asbokid on September 01, 2012, 12:59:04 AM

Quote from: sevenlayermuddle on August 31, 2012, 11:06:06 PM

If the power outage was widespread, there is also the possibility that the cellular network was in some overload with all of the 'help' calls being made, and that it disabled 3G data as a defensive measure to preserve it's own bandwidth.

Yeah, maybe. UMTS is a bit of a damp squib.  It shouldn't really be called "3G" but maybe just "2½G". I was told that it doesn't work at all well as it approaches capacity - being very "noise-limited". The more subscribers trying to place calls or connect, the worse it gets - each seeing the others as channel noise.  UMTS also uses a proprietary CDMA solution from Qualcomm which was chosen above more superior multiple access methods..

Quote

Up until a few years ago that scenario would have been unlikely as not many people would actually have noticed, or even cared about, an power cut at 5:30am in August.  But recently British Gas, in order to line the pockets of senior management save the planet , have been rolling out smart meters that, among other duties I understand, use the mobile phone network to 'phone home' when problems arise. 

In the almost unthinkable circumstance that that that pillar of society, British Gas, may not have thought this through, I wonder if it might result in network overload whenever a power outage arises?

A British Gas Smart Meter would be a great candidate for a Teardown Tuesday by Ozzie electronic engineer, Dave Jones..   Last week he did a teardown (dismantling) of an Emergency Parachute Release System!  That's probably one that belongs in the bin afterwards!

cheers, a

[youtube]http://www.youtube.com/watch?v=9-wzPTiLz5c[/youtube]

Title: Re: Power Cut
Post by: UncleUB on September 01, 2012, 09:47:21 AM

Quote from: sevenlayermuddle on August 31, 2012, 11:06:06 PM

If the power outage was widespread, there is also the possibility that the cellular network was in some overload with all of the 'help' calls being made, and that it disabled 3G data as a defensive measure to preserve it's own bandwidth.


Up until a few years ago that scenario would have been unlikely as not many people would actually have noticed, or even cared about, an power cut at 5:30am in August.  But recently British Gas, in order to line the pockets of senior management save the planet , have been rolling out smart meters that, among other duties I understand, use the mobile phone network to 'phone home' when problems arise. 

In the almost unthinkable circumstance that that that pillar of society, British Gas, may not have thought this through, I wonder if it might result in network overload whenever a power outage arises?

Well tbh I was asleep,but my OH was just about to get up to make a cuppa when she noticed the digital clock go off at the side of the bed,so a prod in my ribs and that was that..one up all up  ;D

After I couldn't access data on my phone I phoned our council emergency helpline to see if they knew anything as the street lights were off......they didn't  ???,all they did was log down that I had reported a fault with the street lighting.

After the power came on I logged onto the appropriate electricity supply website to be told there was a fault,not much good if you can't check to start with  ;D

Anyway thanks one and all for your in depth explanations  :)

Title: Re: Power Cut
Post by: sevenlayermuddle on September 01, 2012, 10:06:38 AM

Reminds me a few years ago we had a power cut.  I wanted to know who to phone, so had a look at the last bill to see if it listed the distribution company's emergency contact details and it did, but not a phone number, just  an address. 

Clearly, the expectation was I would be satisfied by just writing to them, telling them I had an emergency.   :D

Title: Re: Power Cut
Post by: silversurfer44 on September 01, 2012, 10:36:09 AM

I'm surprised at the 7LM I thought they would have had an email address.

Title: Re: Power Cut
Post by: sevenlayermuddle on September 01, 2012, 11:15:24 AM

Quote from: silversurfer44 on September 01, 2012, 10:36:09 AM

I'm surprised at the 7LM I thought they would have had an email address.

:lol:

Title: Re: Power Cut
Post by: sheddyian on September 01, 2012, 11:28:10 AM

About 3 years ago, the power went out late one night with a good 30 seconds or so of flickering lights first.  I went to phone the power company, only to find that the phone was crackling and fizzing, and then the line went dead.  (I'd already plugged in a wired telephone that didn't need external power!)

I went up the road to the local exchange, imagining everything in darkness, but it wasn't - only a few neighbours near me were out, and the phone box by the exchange worked fine, so I reported the electricity and phone faults.

It turned out the electricity cable running under the pavement nearby had melted underneath the tarmac, and taken out the nearby phone cables as well!  I think we were 3 days without electricity and 5 days without telephone whilst the cables were replaced.

Ian