On 11/08/2021 02:31, williamwright wrote:
> On 10/08/2021 20:10, MB wrote:
>> On 10/08/2021 19:50, Mark Carver wrote:
>>> Apparently the fire is out, only one building out of four has been
>>> affected and the mast itself, and there are concerns about the
>>> structural integrity of it, so until that's determined, everyone has to
>>> keep 300m away.
>>
>> I don't think I would like to be 300 yards away from a collapsing 1000
>> ft mast!
>
> Yes but factor in your running speed and you're probably just OK.

Certainly not on rough ground, barely even on a smooth surface and even
if you're a supreme athlete, see below, but, as others have said, the
whiplash of breaking guy cables is likely to be much more dangerous.

This is all from long distance memory, with all that entails for
inaccuracy of detail. In the song 'North Sea Tug', the author, Harry
Robertson, who also more famously wrote 'Little Pot Stove' on Nic Jones'
'Penguin Eggs' album, describes towing a floating dock in a gale, the
tow-rope parting, and cutting a shipmate in two.

There are guitarists in every genre who stupidly leave the trailing ends
of the strings at the guitar's machine head flying about freely, instead
of trimming them or coiling them up safely, and this is a hazard not
just to themselves but to others also, and ISTR a story of one
unfortunate female bystander being blinded in one eye but such an idiot
in a crowded club. On a similar but much less serious topic, I was in a
folk club once where the performer was retuning his guitar, shrinking
back away from it with a nervous expression on his face saying: "The guy
who taught me this tuning says the the trouble with it is that it breaks
a lot of third strings ..." TWANG!

But to return to the falling mast, as a worst case scenario - I think
it must be worst case because in reality it will crumple with most of
the bits still being at least partially connected to each other, which
will slow things down - let's assume that the top of it, or debris
therefrom, falls freely under its own weight from 1,000ft, that the
falling material has no initial velocity, and normal gravitational
acceleration of 32ft/sec^2. From memory, always dangerous when trying
to remember far distantly used maths but I'll go for it, the usual
equation to use is ...
s = ut + gt^2/2
.... where s is the distance travelled in time t seconds, u is the
initial velocity, here zero, and g is the 32ft/sec^2 gravitational
acceleration.

This gives us:
1000 = 32*t^2/2
2000/32 = t^2
t = sqr(2000/32) = nearly 8 seconds to get clear.

For comparison, Usain Bolt took 9.58 seconds to run 100m which is as
near as dammit 328 ft, only a third of the height of the mast, so given
that and the extra danger from whip-lashing cables and anything that
might be even mildly explosive when exposed to fire or structural
damage, I think I'd rather be significantly further away than 300 yards
= 900 ft.

--

Fake news kills!

I may be contacted via the contact address given on my website:
www.macfh.co.uk

On 11/08/2021 13:12, Brian Gregory wrote:
> AIUI DAB isn't literally just relayed.
> It's fed by satellite and presumably a GPS clock is used to synchronise
> it. But still fairly easy to do.

A transmitter fed by satellite is a relay, it is a vague term anyway.

On 11/08/2021 13:40, SH wrote:
> As I understand it, Txes are unmanned.
>
> There is a national monitoring centre at Emley Moor that is manned 24/7....
>
> > Is it significant that an engineer was on site to be able to report
> the fire?
>
> Yes, the press have reported that it was an engineer on site who made
> the initial call to the fire service.

All sites have been unmanned for many years.

The analogue UHF TV network was planned as unmanned from the start, new
sites were manned for a few months because there could be more faults
during that time.

The big VHF sites were manned but the VHF relays were unmanned though
there was a period when there was someone living near them.

My first site was unusual in being VHF radio & TV with UHF TV that was
manned 24/7. The only one like that.

In article <sf0jte$4s7$1@dont-email.me>,
MB <MB@nospam.net> wrote:
> On 11/08/2021 13:40, SH wrote:
> > As I understand it, Txes are unmanned.
> >
> > There is a national monitoring centre at Emley Moor that is manned 24/7....
> >
> > > Is it significant that an engineer was on site to be able to report
> > the fire?
> >
> > Yes, the press have reported that it was an engineer on site who made
> > the initial call to the fire service.

> All sites have been unmanned for many years.

> The analogue UHF TV network was planned as unmanned from the start, new
> sites were manned for a few months because there could be more faults
> during that time.

> The big VHF sites were manned but the VHF relays were unmanned though
> there was a period when there was someone living near them.

> My first site was unusual in being VHF radio & TV with UHF TV that was
> manned 24/7. The only one like that.

Sutton Coldfield, NHT or Wenvoe?

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

"Theo" <theom+news@chiark.greenend.org.uk> wrote in message
news:T5h*3ppry@news.chiark.greenend.org.uk...
> “North Yorkshire Fire and Rescue Service worked to control the fire in
> difficult circumstances and extinguished a fire in a single-storey stone
> building and a 315ft transmitter mast.
>
> “Only one building in a complex of four was affected and there are
> concerns
> about the structural integrity of the mast.
>
>
> confirming it does seem to have been the mast itself on fire.

The structural integrity of the mast could be affected in two ways (or a
combination of them):

- fire is only in the building, but some of the hot gases go up the mast as
a chimney

- fire starts in the building and then spreads to the flammable insulation
on cables that run up the mast

I agree that "extinguished a fire in a single-storey stone building and a
315ft transmitter mast" does tend to suggest that the latter is the case.
Someone has mangled feet and metres: Bilsdale mast is about 315 *metres*
tall - hence the reports of a 300 metre exclusion zone.

I presume the connection between the transmitters and the mast is a hollow
waveguide rather than just a cable, so there is scope for smoke/fumes from
the transmitter building to flow up the "chimney" of the mast.

As a matter of interest, which UK mast has the highest aerial above sea
level - mast height plus height of land at foot of mast? I wonder how the
exact height of a mast is decided upon - why make it 315 m rather than 310 m
or 320 m, for example? How does coverage vary with height once you get to
roughly 300 m above ground or 700 m above sea level?

"NY" <me@privacy.invalid> wrote in message
news:sf0n2q$slo$1@dont-email.me...
> As a matter of interest, which UK mast has the highest aerial above sea
> level - mast height plus height of land at foot of mast? I wonder how the
> exact height of a mast is decided upon - why make it 315 m rather than 310
> m or 320 m, for example? How does coverage vary with height once you get
> to roughly 300 m above ground or 700 m above sea level?

Ah, I've found the answer - eventually. Winter Hill is the highest antenna:
shorter mast than Belmont, the tallest, but the bottom of the mast is on
much higher ground, so the antenna is at 780 m.
https://www.geograph.org.uk/photo/4862277

Bilsdale at about 700 m is pretty high. Even the original, pre-1969 Emley
Moor was only 650 m (265 ground plus 385 mast).

On Wed 11/08/2021 15:32, NY wrote:
> "Theo" <theom+news@chiark.greenend.org.uk> wrote in message
> news:T5h*3ppry@news.chiark.greenend.org.uk...
>> “North Yorkshire Fire and Rescue Service worked to control the fire in
>> difficult circumstances and extinguished a fire in a single-storey stone
>> building and a 315ft transmitter mast.
>>
>> “Only one building in a complex of four was affected and there are
>> concerns
>> about the structural integrity of the mast.
>>
>>
>> confirming it does seem to have been the mast itself on fire.
>
> The structural integrity of the mast could be affected in two ways (or a
> combination of them):
>
> - fire is only in the building, but some of the hot gases go up the mast
> as a chimney
>
> - fire starts in the building and then spreads to the flammable
> insulation on cables that run up the mast
>
> I agree that "extinguished a fire in a single-storey stone building and
> a 315ft transmitter mast" does tend to suggest that the latter is the
> case. Someone has mangled feet and metres: Bilsdale mast is about 315
> *metres* tall - hence the reports of a 300 metre exclusion zone.
>
> I presume the connection between the transmitters and the mast is a
> hollow waveguide rather than just a cable, so there is scope for
> smoke/fumes from the transmitter building to flow up the "chimney" of
> the mast.
>
>
> As a matter of interest, which UK mast has the highest aerial above sea
> level - mast height plus height of land at foot of mast? I wonder how
> the exact height of a mast is decided upon - why make it 315 m rather
> than 310 m or 320 m, for example? How does coverage vary with height
> once you get to roughly 300 m above ground or 700 m above sea level?

From my memory of attending BWM (Bilsdale West Moor to give it its
exact name) the tower is separate from the building - on most sites it
usually is - and there are cables from the building into the base of
the tower. At Emley pre DSO these were 6½in tubular co-ax which I think
were an aluminium outer. Emley was changed at DSO, I don't know about
BWM, but aluminium burns as we all remember from the Falklands?

On Tuesday, 10 August 2021 at 20:10:04 UTC+1, MB wrote:
> On 10/08/2021 19:50, Mark Carver wrote:
> > Apparently the fire is out, only one building out of four has been
> > affected and the mast itself, and there are concerns about the
> > structural integrity of it, so until that's determined, everyone has to
> > keep 300m away.
> I don't think I would like to be 300 yards away from a collapsing 1000
> ft mast!

Probably not, but then 300m is 984 feet, so you would probably have time to step out of the way.

Here are some stills (1920x1080) from the report on tonight's Tyne Tees
local news programme:

https://i.postimg.cc/rs9PSSv5/vlcsnap-2021-08-11-19h12m10s87.png
https://i.postimg.cc/8cGYJyn1/vlcsnap-2021-08-11-19h12m21s2.png
https://i.postimg.cc/xdWhYjvN/vlcsnap-2021-08-11-19h12m36s118.png
https://i.postimg.cc/vBfjmRhq/vlcsnap-2021-08-11-19h13m30s168.png

The bottom definitely looks a bit fire-ravaged, with large areas of
flaked-off paint and some scorch marks. I imagine the inside is a lot worse,
both because of the smoke/soot and because insulation will have melted. They
said the building which had caught fire was on the opposite side, out of
view of where they were letting the press get to. The reporter made a point
of saying "I'm standing 300 metres away" having mentioned earlier this is
the height of the mast, though confusingly he used feet for the height so
people may not have made the connection between mast height and radius of
exclusion zone.

I hadn't realised that it was also used as a mobile phone mast, so mobile
phone coverage for the area has been lost as well. And being such a high
point, it probably covers such a large area that there won't be other mobile
phone masts for a significant radius, that could serve as backup. Eggs and
only one basket!

BTW, which bozo chose to omit the U from Arqiva. Why can't companies use
real names, rather than made-up computer-generated ones? I wasn't sure till
the reporter said the name whether it was pronounced ark-ee-ver,
ark-eye-ver, arkw-ee-ver, arkw-eye-ver, ark-ivver or ark-wivver. For the
record, he pronounced it ark-ee-ver.

On 11/08/2021 14:56, charles wrote:
>> My first site was unusual in being VHF radio & TV with UHF TV that was
>> manned 24/7. The only one like that.
> Sutton Coldfield, NHT or Wenvoe?

Llandonna!

Like many things it was historic, Llanddona was a medium wave station
that moved up to a TV site. We had some monitoring responsibilities for
Wales during the night which had been carried over from Penmon. There
was line from Wrexham which allowed us to monitor it in the morning.

We even had a nightwatchman.

In article <sf15bd$8po$1@dont-email.me>, NY <me@privacy.invalid> wrote:

>BTW, which bozo chose to omit the U from Arqiva. Why can't companies use
>real names, rather than made-up computer-generated ones? I wasn't sure till
>the reporter said the name whether it was pronounced ark-ee-ver,
>ark-eye-ver, arkw-ee-ver, arkw-eye-ver, ark-ivver or ark-wivver.

The company may have an intended pronunciation, but it's not up to
them. Whatever way you say it is as good as any other, so long as
people know what you mean.

-- Richard

On 11/08/2021 19:35, NY wrote:
> I hadn't realised that it was also used as a mobile phone mast, so mobile
> phone coverage for the area has been lost as well. And being such a high
> point, it probably covers such a large area that there won't be other mobile
> phone masts for a significant radius, that could serve as backup. Eggs and
> only one basket!
>
> BTW, which bozo chose to omit the U from Arqiva. Why can't companies use
> real names, rather than made-up computer-generated ones? I wasn't sure till
> the reporter said the name whether it was pronounced ark-ee-ver,
> ark-eye-ver, arkw-ee-ver, arkw-eye-ver, ark-ivver or ark-wivver. For the
> record, he pronounced it ark-ee-ver.

It will be mainly links carrying mobile phone traffic but there be lots
of other things on it as well.

I always make a point of putting the "U" in the name, just to annoy them.

On 11/08/2021 08:49, MB wrote:
> On 11/08/2021 02:33, williamwright wrote:
>> Why not simply equip them with freesat dishes?
>
> How many thousand Freesat dishes can you install per day?
>
I'm out of patience with people who misunderstand, following an annoying
afternoon with a local facebook group.

Bill

On 11/08/2021 09:02, Mark Carver wrote:
> On 11/08/2021 08:49, MB wrote:
>> On 11/08/2021 02:33, williamwright wrote:
>>> Why not simply equip them with freesat dishes?
>>
>> How many thousand Freesat dishes can you install per day?
>>
>> They have managed to restore services fairly quickly on previous
>> occasions and now better equipped with emergency transmitters, masts etc.
>>
>>
> I gather Arqiva have a containerised Tx set and a mast on the way there.
> I doubt it's a 1000 footer mast though, so I wonder how much signal will
> actually get to the primary urban target area ?
>
> My bet on getting the local FM stations back, is to use Eston Nab
>
> http://tx.mb21.co.uk/gallery/gallerypage.php?txid=759

Even with the existing mast there were big shadow areas below the
shoulders of the moors. Hence the use of Emley in all sorts of
surprising places.

Bill

"MB" <MB@nospam.net> wrote in message news:sf15tm$cun$1@dont-email.me...
> On 11/08/2021 19:35, NY wrote:
>> BTW, which bozo chose to omit the U from Arqiva. Why can't companies use
>> real names, rather than made-up computer-generated ones? I wasn't sure
>> till
>> the reporter said the name whether it was pronounced ark-ee-ver,
>> ark-eye-ver, arkw-ee-ver, arkw-eye-ver, ark-ivver or ark-wivver. For the
>> record, he pronounced it ark-ee-ver.
>
> I always make a point of putting the "U" in the name, just to annoy them.

And I then pronounce it "Arqueever" to annoy them further. A Q without a
following U is very Arabic. I wonder why the normal rule about Q always
being followed by U arose.

In article <sf15gg$a04$1@dont-email.me>,
MB <MB@nospam.net> wrote:
> On 11/08/2021 14:56, charles wrote:
> >> My first site was unusual in being VHF radio & TV with UHF TV that was
> >> manned 24/7. The only one like that.
> > Sutton Coldfield, NHT or Wenvoe?

> Llandonna!

One of the few main stations that I didn't visit.

> Like many things it was historic, Llanddona was a medium wave station
> that moved up to a TV site. We had some monitoring responsibilities for
> Wales during the night which had been carried over from Penmon. There
> was line from Wrexham which allowed us to monitor it in the morning.

> We even had a nightwatchman.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 11/08/2021 20:50, charles wrote:
>> Llandonna!
> One of the few main stations that I didn't visit.
>
>

There a few oddities about it, I think the EIC was also EiC of Bangor
studio when I went there and Llandonna was effectively run by the AEiC.

We had an early alarm system where you hasd to push a button every 30
minute - the nightwatchman took care of that whilst we got some sleep :-)

The diesel was quite a large modern one which could easily run the whole
site but no one trusted it then one day when being tested, a pipe blew
off spraying hot coolant everywhere.

We even had a "tower collapse"! During the investiture there were lots
of links going through the site, one used an Eagle Tower. Someone
decided to guy the Eagle Tower and tied the guy rope to a Land Rover
parked nearby. Unfortunately someone moved the Land Rover!

On 11/08/2021 14:39, MB wrote:
> All sites have been unmanned for many years.

Surely the cost of paying somebody to be there would be small compared
to the cost of the electricity for a main transmitter?

--
Brian Gregory (in England).

On 11/08/2021 21:32, MB wrote:
> On 11/08/2021 20:50, charles wrote:
>>> Llandonna!
>> One of the few main stations that I didn't visit.
>>
>>
>
> There a few oddities about it, I think the EIC was also EiC of Bangor
> studio when I went there and Llandonna was effectively run by the AEiC.
>
> We had an early alarm system where you hasd to push a button every 30
> minute - the nightwatchman took care of that whilst we got some sleep  :-)
>
> The diesel was quite a large modern one which could easily run the whole
> site but no one trusted it then one day when being tested, a pipe blew
> off spraying hot coolant everywhere.
>
> We even had a "tower collapse"!  During the investiture there were lots
> of links going through the site, one used an Eagle Tower.  Someone
> decided to guy the Eagle Tower and tied the guy rope to a Land Rover
> parked nearby.  Unfortunately someone moved the Land Rover!
>
>

Is "MB" of Mike Brown of www.MB21.co.uk fame?

In article <inir1iFqs0hU1@mid.individual.net>,
Brian Gregory <void-invalid-dead-dontuse@email.invalid> wrote:
> On 11/08/2021 14:39, MB wrote:
> > All sites have been unmanned for many years.

> Surely the cost of paying somebody to be there would be small compared
> to the cost of the electricity for a main transmitter?

You wouldn't just need one person. 24/7 coverage would probably require 12
at a minimum + sick & holiday relief.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 11/08/2021 21:42, Brian Gregory wrote:
> Surely the cost of paying somebody to be there would be small compared
> to the cost of the electricity for a main transm

But what is he going to do all day?

I seem to remember that reliability was improved when there was no one
fiddling with the equipment.

Post-WWII, some sites had a "TA In Attendance". He lived close to the
transmitter siteso was available to quickly respond to a fault. It
should be described in Pawley but I think the unions did not like it
because it tended to be retired managers who got the jobs.

In article <seuiku$555$1@dont-email.me>, MB <MB@nospam.net> scribeth
thus
>On 10/08/2021 18:28, tony sayer wrote:
>> Bet it wasn't, that sort of structure will be well earthed and
>> protected!..
>
>I have known lots of "well earthed and protected" to be damaged (or even
>destroyed) by lightning. I spent many hour restoring service at places
>after lightning. All had been "well earthed and protected".
>
>Lightning is strange stuff, I went to one hilltop site. Most damage was
>the monitoring equipment as usual, the telephone line was dead but OK
>after I changed the BT fuse.
>
>We had a metal equipment trolley that was pushed up against the metal
>wall heater. The telephone was on the trolley with the handset "coily"
>cord trailing over the edge. I pushed the trolley but would not move
>until I gave a sharp push - it was spot welded to the metal wall heater.
> Then noticed that the "coily" cord was discoloured where it trailed
>over the metal edge of the trolley. But it still worked!
>

Well somewhere like Bilsdale a 315 metre ish long metal cylinder with
12?, stays all earthed and the mast itself well earthed but what the
main Lightning protection idea is, is to shunt the discharge around what
needs protecting and I'd very much expect that will work very well.

However other smaller sites?, some a few with a domestic stylee mains
type earthed rod connected by a cable around 1/4 inch in diameter!

Not the best scheme!
--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

In article <seujue$qsq$1@dont-email.me>, Woody <harrogate3@ntlworld.com>
scribeth thus
>On Tue 10/08/2021 20:05, MB wrote:
>> On 10/08/2021 18:28, tony sayer wrote:
>>> Bet it wasn't, that sort of structure will be well earthed and
>>> protected!..
>>
>> I have known lots of "well earthed and protected" to be damaged (or even
>> destroyed) by lightning.  I spent many hour restoring service at places
>> after lightning.  All had been "well earthed and protected".
>>
>> Lightning is strange stuff, I went to one hilltop site.  Most damage was
>> the monitoring equipment as usual, the telephone line was dead but OK
>> after I changed the BT fuse.
>>
>> We had a metal equipment trolley that was pushed up against the metal
>> wall heater. The telephone was on the trolley with the handset "coily"
>> cord trailing over the edge. I pushed the trolley but would not move
>> until I gave a sharp push - it was spot welded to the metal wall heater.
>>  Then noticed that the "coily" cord was discoloured where it trailed
>> over the metal edge of the trolley.  But it still worked!
>>
>
>
>I remember an ambulance customer taking a lightning hit on a 30m mast at
>the side of the Control building. The mast had a 4ft 1500MHz dish and a
>shrouded yagi (a.k.a. donkey's plonker) for analogue links. The
>equipment was on the first floor so the cables came off the tower at
>about 5m.
>
>The 1500MHz link equipment was untouched, as was the analogue mux
>attached to it and the radio control equipment. On the very end was a
>PDP11 computer (remember them?) and it took out the 'christmas tree' in
>the PDP and fused a four pair telephone cable inside a 2" steel trunk
>between the equipment room and the Control Room next door.

Have to ask just how well that was configured in the overall sense.

Nothing strange re Lightning in many ways its quite predictable but the
size of a discharge that can be another matter.

Messers Furse of Nottingham used to do a very good booklet advising how
to configure such systems. We tend it think of it as pure DC by it had a
very good example of how you should be rigging a down conductor over a
roof and done the way there was a picture of it going behind a Gutter
instead of over it, that small loop was quite inductive and there was a
picture of quite a substantial burn from the top of the conductor to the
bottom caused by the ever so slight inductance.

There is a rolling sphere method which is very useful most tend to
think lightning hits the top of a building t'aint so. Few years ago just
been working at Ely cathedral, left there and a thunderstorm came from
nowhere just caught sight of a very large strike hit around half way up
the tower nowhere near the top . That place is very well protected!

Its like RF, its understandable, just need some bloody understanding!...

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

BBC News

Bilsdale transmitter fire: TV and radio services largely restored

https://www.bbc.co.uk/news/uk-england-tees-58181439

On 11/08/2021 23:37, MB wrote:
> BBC News
>
> Bilsdale transmitter fire: TV and radio services largely restored
>
> https://www.bbc.co.uk/news/uk-england-tees-58181439

That's certainly the title but reading the text rather leaves one
wondering about exactly what has been restored and how well it has been
restored.

--
Brian Gregory (in England).