From Newsgroup: uk.tech.broadcast

Kistening to the nice old film at
https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):
"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament supports".
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

"J. P. Gilliver" wrote:

Kistening to the nice old film at
https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):

"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament supports".

"not only their anodes, but their filament supports"

--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

Andy Burns <usenet@andyburns.uk> wrote:

"J. P. Gilliver" wrote:

Kistening to the nice old film at https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):

"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament supports".

"not only their anodes, but their filament supports"

That would be almost correct: it's not the supports that need cooling
but the seals where the filament wires enter the bulb.

Big transmitting valves usually have directly-heated cathodes
("filaments") which are made of solid uncoated tungsten or thoriated
tungsten; a separate emissive coating would be stripped off by the high voltages. This means that the filament heating power must be supplied
at low voltage and high current to avoid too great a change of potential
along the cathode/filament which would cause the grid-cathode potential
to vary from one end to the other and make biassing difficult. The
problem is even worse with A.C. heating, which is liable to cause hum.

The connections to the filament are of large cross-section to carry the
current (and, incidentally, minimise the inductive impedance in the
cathode circuit at R.F.), so a lot of heat is transferred along them
towards the glass/metal seals where they enter the evacuated envelope.
These seals rely on matching the thermal coefficients of expansion of
the metal core and the surrounding glass, so that their expansion is approximately equal over a range of temperatures.

This means the seals must be cooled to keep the peak temperature down to
the point where the compressive or tension stresses in the seals are
within their design limits and don't either shatter the glass or pull
the seal apart. Often this is done by blowing air onto the seals
(economically by bleeding-off some of the air that has already cooled
the anode). I suppose water-cooled seals could be used equally well but
I have only read older textbooks and they don't mention that
possibility.
--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

Andy Burns <usenet@andyburns.uk> wrote:

"J. P. Gilliver" wrote:

Kistening to the nice old film at https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):

"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament supports".

"not only their anodes, but their filament supports"

What a charming film. I visited Droitwich when I was at Evesham in '68. Somebody (maybe the Ariel club) arranged a charabanc outing for those
few of us fledgeling TAs who were interested.

The cooling water in the film reminds me of the valves in the final amps
of the new 250KW senders* then being installed at Skelton SW station.
They had external anodes sitting in de-ionised water baths and cooled by boiling the water.

* Marconi BD272Cs with two BY1144Ls in class C push-pull in the final
and similar (I think in class B) in the modulator. Final and modulator
each had 11kV DC at 26A on the anodes and ran very hot.
--
^-^. Sn!pe, bird-brain. All that was old is new again.

My pet rock Gordon just is.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 2026/6/28 22:59:33, Liz Tuddenham wrote:

Andy Burns <usenet@andyburns.uk> wrote:

"J. P. Gilliver" wrote:

Kistening to the nice old film at
https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):

"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament >>> supports".

"not only their anodes, but their filament supports"

That would be almost correct: it's not the supports that need cooling
but the seals where the filament wires enter the bulb.

[fascinating stuff deleted]

This means the seals must be cooled to keep the peak temperature down to
the point where the compressive or tension stresses in the seals are
within their design limits and don't either shatter the glass or pull
the seal apart. Often this is done by blowing air onto the seals (economically by bleeding-off some of the air that has already cooled
the anode). I suppose water-cooled seals could be used equally well but
I have only read older textbooks and they don't mention that
possibility.

Thanks for a fascinating explanation!

(I still covet that meter seen - fleetingly - in the "opening of
television" film [the Adele Dixon one], that is labelled gallons per
minute.)
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf

If you bate your breath do you catch a lung fish?
(Glynn Greenwood 1996-8-23.)
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On Sun, 28 Jun 2026 23:01:42 +0100, snipeco.2@gmail.com (Sn!pe) wrote:

Andy Burns <usenet@andyburns.uk> wrote:

"J. P. Gilliver" wrote:

Kistening to the nice old film at
https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):

"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament >> > supports".

"not only their anodes, but their filament supports"

What a charming film. I visited Droitwich when I was at Evesham in '68. >Somebody (maybe the Ariel club) arranged a charabanc outing for those
few of us fledgeling TAs who were interested.

The cooling water in the film reminds me of the valves in the final amps
of the new 250KW senders* then being installed at Skelton SW station.
They had external anodes sitting in de-ionised water baths and cooled by >boiling the water.

* Marconi BD272Cs with two BY1144Ls in class C push-pull in the final
and similar (I think in class B) in the modulator. Final and modulator
each had 11kV DC at 26A on the anodes and ran very hot.

I must have been in the same group, as we've established we were both
on TA 28, and I also remember a visit to Droitwich. I particularly
remember the huge goldfish in the cooling water tank. The water is
circulated in order to cool it, but still remains quite warm, and
apparently this enables the fish to thrive.

Another memory of Droitwich was the fact that any workbench
oscilloscope at Wood Norton with an open circuit probe would display
not a clear thin horizontal line as you'd expect with no input signal,
but a fuzzy line, pulsating in an apparently random manner. My
curiosity piqued, I eventually found with the aid of a portable radio
that the pulsations weren't random at all but perfectly synchronised
to the audio on Radio 2. FM reception was rubbish there, but you could
easily pick up the longwave signal without even a tuned circuit.

By the way, did anyone else notice in the credits at the end of the
film, sound by E. A. Pawley? I think I've seen that name before.

Rod.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 29/06/2026 11:04, Roderick Stewart wrote:

On Sun, 28 Jun 2026 23:01:42 +0100, snipeco.2@gmail.com (Sn!pe) wrote:

Andy Burns <usenet@andyburns.uk> wrote:

"J. P. Gilliver" wrote:

Kistening to the nice old film at
https://www.youtube.com/watch?v=hCoheqhlQ_k (about 3:45 in):

"a continuous stream of water must circulate round, not only their
anodes, but" - what does it say? It sounds to me like "to their filament >>>> supports".

"not only their anodes, but their filament supports"

What a charming film. I visited Droitwich when I was at Evesham in '68.
Somebody (maybe the Ariel club) arranged a charabanc outing for those
few of us fledgeling TAs who were interested.

The cooling water in the film reminds me of the valves in the final amps
of the new 250KW senders* then being installed at Skelton SW station.
They had external anodes sitting in de-ionised water baths and cooled by
boiling the water.

* Marconi BD272Cs with two BY1144Ls in class C push-pull in the final
and similar (I think in class B) in the modulator. Final and modulator
each had 11kV DC at 26A on the anodes and ran very hot.

I must have been in the same group, as we've established we were both
on TA 28, and I also remember a visit to Droitwich. I particularly
remember the huge goldfish in the cooling water tank. The water is
circulated in order to cool it, but still remains quite warm, and
apparently this enables the fish to thrive.

Another memory of Droitwich was the fact that any workbench
oscilloscope at Wood Norton with an open circuit probe would display
not a clear thin horizontal line as you'd expect with no input signal,
but a fuzzy line, pulsating in an apparently random manner. My
curiosity piqued, I eventually found with the aid of a portable radio
that the pulsations weren't random at all but perfectly synchronised
to the audio on Radio 2. FM reception was rubbish there, but you could
easily pick up the longwave signal without even a tuned circuit.

By the way, did anyone else notice in the credits at the end of the
film, sound by E. A. Pawley? I think I've seen that name before.

Rod.

yes, I know the name. He wrote the book "BBC Engineering 1922-1972"
which is sitting on my bookshelf.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 29/06/2026 11:04, Roderick Stewart wrote:

Another memory of Droitwich was the fact that any workbench
oscilloscope at Wood Norton with an open circuit probe would display
not a clear thin horizontal line as you'd expect with no input signal,
but a fuzzy line, pulsating in an apparently random manner. My
curiosity piqued, I eventually found with the aid of a portable radio
that the pulsations weren't random at all but perfectly synchronised
to the audio on Radio 2. FM reception was rubbish there, but you could
easily pick up the longwave signal without even a tuned circuit.

Criggion was even better, their party trick was to draw a spark off
someone's nose in the coil chamber as well as a 5 ft fluorescent tube
lighting up as someone held it.

You also seemed to 'hear' the pulses going out every five seconds(?)






--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 29/06/2026 11:30, Charles Hope wrote:

yes, I know the name. He wrote the book "BBC Engineering 1922-1972"
which is sitting on my bookshelf.

It can be downloaded from somewhere on the BBC website I think.

Off topic but the book on Radar in Scotland in WWII can now be
downloaded. Some good pictures in there also.



--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 2026/6/29 14:48:18, JMB99 wrote:

On 29/06/2026 11:30, Charles Hope wrote:

yes, I know the name. He wrote the book "BBC Engineering 1922-1972"
which is sitting on my bookshelf.

It can be downloaded from somewhere on the BBC website I think.

Off topic but the book on Radar in Scotland in WWII can now be
downloaded. Some good pictures in there also.

For some interesting observations on WWII radar, I recommend (if you can
find it) "Glide Path", by Arthur C. Clarke (the science-fiction author);
it's actually not fiction, but an account of his experiences in that
field. (Including a furious RAF bigwig coming into the radar room, after
they'd offered to "talk him down" as a demonstration of radar's
capabilities, saying if he'd followed their instructions, he'd have
landed in a swamp or something; they'd actually followed the blip from a
much larger 'plane which had landed at the same time, quite unaware of
the radar experiments). It's a nicely-written book - though not fiction,
his writing skills make it seem you are there.


--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf

did you hear about the guy who was frozen to absolute zero?
He was 0K ...
- Jason in alt.windows7.general (and three other 'groups), 2018-5-1
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

J. P. Gilliver <G6JPG@255soft.uk> wrote:

On 2026/6/29 14:48:18, JMB99 wrote:

On 29/06/2026 11:30, Charles Hope wrote:

yes, I know the name. He wrote the book "BBC Engineering 1922-1972"
which is sitting on my bookshelf.

It can be downloaded from somewhere on the BBC website I think.

Off topic but the book on Radar in Scotland in WWII can now be
downloaded. Some good pictures in there also.

For some interesting observations on WWII radar, I recommend (if you can
find it) "Glide Path", by Arthur C. Clarke (the science-fiction author);
it's actually not fiction, but an account of his experiences in that
field. (Including a furious RAF bigwig coming into the radar room, after they'd offered to "talk him down" as a demonstration of radar's
capabilities, saying if he'd followed their instructions, he'd have
landed in a swamp or something; they'd actually followed the blip from a
much larger 'plane which had landed at the same time, quite unaware of
the radar experiments). It's a nicely-written book - though not fiction,
his writing skills make it seem you are there.

There is a very strong disclaimer at the start of the book that the
characters are entirely ficticious and nobody should try to connect them
with real people. One of the characters appears to me to be amazingly
similar to Fred Deveraux, the Editor of Wireless World, who published
Clarke's famous paper on Satellites.


There is also a hidden joke about the appearance of one of the radar
trucks - it is referred to as a "Chick Sale" but the reference is not explained.
--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 2026/6/30 9:4:36, Liz Tuddenham wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

[]

On 29/06/2026 11:30, Charles Hope wrote:

[]

Off topic but the book on Radar in Scotland in WWII can now be
downloaded. Some good pictures in there also.

For some interesting observations on WWII radar, I recommend (if you can
find it) "Glide Path", by Arthur C. Clarke (the science-fiction author);
it's actually not fiction, but an account of his experiences in that

[]

There is a very strong disclaimer at the start of the book that the characters are entirely ficticious and nobody should try to connect them
with real people. One of the characters appears to me to be amazingly similar to Fred Deveraux, the Editor of Wireless World, who published Clarke's famous paper on Satellites.

Whatever, I found it a both interesting and enjoyable read.
(I'm just glad to find someone else who's actually come across it!)

There is also a hidden joke about the appearance of one of the radar
trucks - it is referred to as a "Chick Sale" but the reference is not explained.

Schicksaal?

--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf

Q. Why did the chicken cross the Mobius strip?
A. To get to the same side.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

J. P. Gilliver <G6JPG@255soft.uk> wrote:

On 2026/6/30 9:4:36, Liz Tuddenham wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

[]

On 29/06/2026 11:30, Charles Hope wrote:

[]

Off topic but the book on Radar in Scotland in WWII can now be
downloaded. Some good pictures in there also.

For some interesting observations on WWII radar, I recommend (if you can >> find it) "Glide Path", by Arthur C. Clarke (the science-fiction author); >> it's actually not fiction, but an account of his experiences in that

[]

There is a very strong disclaimer at the start of the book that the characters are entirely ficticious and nobody should try to connect them with real people. One of the characters appears to me to be amazingly similar to Fred Deveraux, the Editor of Wireless World, who published Clarke's famous paper on Satellites.

Whatever, I found it a both interesting and enjoyable read.
(I'm just glad to find someone else who's actually come across it!)

There is also a hidden joke about the appearance of one of the radar
trucks - it is referred to as a "Chick Sale" but the reference is not explained.

Schicksaal?

No.

Chick (Charles) Sale was an actor who also wrote a book called "The
Specialist" about a general carpenter who decides to specialise in
making privvies. The wooden excrescence on the back of one of the
trucks resembled an outside privvy, so calling it a "Chick Sale" was an
'in' joke among the Americans, which the British didn't understand.
--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

Sn!pe wrote:

Marconi BD272Cs with two BY1144Ls in class C push-pull in the final
and similar (I think in class B) in the modulator. Final and modulator
each had 11kV DC at 26A on the anodes and ran very hot.

I found it odd that the power to each valve was given in hp, but I
suppose mains electricity was relatively new-fangled for many people to
be familiar with kW?
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 2026/6/30 10:28:3, Liz Tuddenham wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

On 2026/6/30 9:4:36, Liz Tuddenham wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

[]

On 29/06/2026 11:30, Charles Hope wrote:

[]

Off topic but the book on Radar in Scotland in WWII can now be

[]

There is also a hidden joke about the appearance of one of the radar
trucks - it is referred to as a "Chick Sale" but the reference is not
explained.

Schicksaal?

No.

Chick (Charles) Sale was an actor who also wrote a book called "The Specialist" about a general carpenter who decides to specialise in
making privvies. The wooden excrescence on the back of one of the
trucks resembled an outside privvy, so calling it a "Chick Sale" was an
'in' joke among the Americans, which the British didn't understand.

Ah. Reminds me (and slightly back on-topic!) of the lengthy discussion
we had here a few years ago, as to why OB control vans are referred to
as "scanner"; the _consensus_ was that it /was/ derived from Baird's OB
vehicle that covered the Derby (and thus contained a Baird-system mirror scanner), though other ideas (such as it containing the central sync.
generator for all the outside cameras) remained supported by factions.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf

"Bother," said Pooh, as Windows crashed into piglet.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 2026/6/30 10:44:5, Andy Burns wrote:

Sn!pe wrote:

Marconi BD272Cs with two BY1144Ls in class C push-pull in the final
and similar (I think in class B) in the modulator. Final and modulator
each had 11kV DC at 26A on the anodes and ran very hot.

I found it odd that the power to each valve was given in hp, but I
suppose mains electricity was relatively new-fangled for many people to
be familiar with kW?

Perhaps, also, that Diesel generators - so, engines - were involved, and
people were used to measuring engines in horsepower.

Unifying various sorts of energy (I would say) has only really come in
(among the general public, that is) since we've been messing about with
energy companies; gas used to be (though before my time) measured in
"therms", then cubic {feet then metres}. (Line from one of Stanley
Holloway's monologues about Albert, "and best gas is three ha'pence a
therm" - though that was for comic effect, as he was talking about
anaesthetic gas.)
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()ALIS-Ch++(p)Ar++T+H+Sh0!:`)DNAf

"Bother," said Pooh, as Windows crashed into piglet.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 30 Jun 2026 at 10:28:03 BST, "Liz Tuddenham" <Liz Tuddenham> wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

On 2026/6/30 9:4:36, Liz Tuddenham wrote:

J. P. Gilliver <G6JPG@255soft.uk> wrote:

[]

On 29/06/2026 11:30, Charles Hope wrote:

[]

Off topic but the book on Radar in Scotland in WWII can now be
downloaded. Some good pictures in there also.

For some interesting observations on WWII radar, I recommend (if you can >>>> find it) "Glide Path", by Arthur C. Clarke (the science-fiction author); >>>> it's actually not fiction, but an account of his experiences in that

[]

There is a very strong disclaimer at the start of the book that the
characters are entirely ficticious and nobody should try to connect them >>> with real people. One of the characters appears to me to be amazingly
similar to Fred Deveraux, the Editor of Wireless World, who published
Clarke's famous paper on Satellites.

Whatever, I found it a both interesting and enjoyable read.
(I'm just glad to find someone else who's actually come across it!)

There is also a hidden joke about the appearance of one of the radar
trucks - it is referred to as a "Chick Sale" but the reference is not
explained.

Schicksaal?

No.

Chick (Charles) Sale was an actor who also wrote a book called "The Specialist" about a general carpenter who decides to specialise in
making privvies. The wooden excrescence on the back of one of the
trucks resembled an outside privvy, so calling it a "Chick Sale" was an
'in' joke among the Americans, which the British didn't understand.

Now that is a wonderful book! Highly recommended.

I have acquired a copy of Glide Path, too. I've never read it.
--
Vita non est vivere sed valere vita est
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 30/06/2026 10:28, Liz Tuddenham wrote:

Chick (Charles) Sale was an actor who also wrote a book called "The Specialist" about a general carpenter who decides to specialise in
making privvies.

There's a short film based on it.
--
Max Demian
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

Max Demian <max_demian@bigfoot.com> wrote:

On 30/06/2026 10:28, Liz Tuddenham wrote:

Chick (Charles) Sale was an actor who also wrote a book called "The Specialist" about a general carpenter who decides to specialise in
making privvies.

There's a short film based on it.

...and a song by Frank Crumit.
--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 30/06/2026 18:56, J. P. Gilliver wrote:

Ah. Reminds me (and slightly back on-topic!) of the lengthy discussion
we had here a few years ago, as to why OB control vans are referred to
as "scanner"; the_consensus_ was that it/was/ derived from Baird's OB
vehicle that covered the Derby (and thus contained a Baird-system mirror scanner), though other ideas (such as it containing the central sync. generator for all the outside cameras) remained supported by factions.

Earliest use of the term thT can find.





Daily Mirror - Tuesday 19 January 1937

MYSTERY VANS TO TELEVISE THE CORONATION
A SPECIAL CORRESPONDENT
THREE grey-green plain vans are on their way to the B. B. C. rCo a vital
but "hush-hush" link in the B. B. C.'s Coronation broadcasts of television. Yesterday I was able to inspect the layouts of these mysterious vans.
The first has a little window at the side through which the nose of a television scanner peeps. This van will be driven along the route to
vantage points where the B. B. C. can televise the Coronation procession. Following it will be a second van containing apparatus costing more than -u4,000. There is a special ultra-short-wave transmitter, working below 7 metres, which will broadcast the television from the route to the B. B. C. Signals will be picked up by several receivers around London rCo one of
them probably on Broadcasting House itself rCo and re-broadcast from the television station at Alexandra Palace.
The third van contains the other B. B. C. secret apparatus. If the
electric power mains break down it will not stop the broadcast, for the
B. B. C. " makes its own juice."
Post Office engineers are laying down special cables all over London, so
that travelling B. B. C. commentators can plug in their microphones.
"Lobby"rCo Mr. de Lotbiniere. the Outside Broadcast DirectorrCois still
giving tests to special commentators who will describe on the air the
progress of the ceremony and the procession.
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: uk.tech.broadcast

On 01/07/2026 13:07, JMB99 wrote:

Daily Mirror - Tuesday 19 January 1937

MYSTERY VANS TO TELEVISE THE CORONATION
A SPECIAL CORRESPONDENT
THREE grey-green plain vans are on their way to the B. B. C. rCo a vital
but "hush-hush" link in the B. B. C.'s Coronation broadcasts of television. Yesterday I was able to inspect the layouts of these mysterious vans.
The first has a little window at the side through which the nose of a television scanner peeps. This van will be driven along the route to
vantage points where the B. B. C. can televise the Coronation procession. Following it will be a second van containing apparatus costing more than -u4,000. There is a special ultra-short-wave transmitter, working below 7 metres, which will broadcast the television from the route to the B. B. C. Signals will be picked up by several receivers around London rCo one of
them probably on Broadcasting House itself rCo and re-broadcast from the television station at Alexandra Palace.
The third van contains the other B. B. C. secret apparatus. If the
electric power mains break down it will not stop the broadcast, for the
B. B. C. " makes its own juice."
Post Office engineers are laying down special cables all over London, so that travelling B. B. C. commentators can plug in their microphones. "Lobby"rCo Mr. de Lotbiniere. the Outside Broadcast DirectorrCois still giving tests to special commentators who will describe on the air the progress of the ceremony and the procession.

I wonder why everything was so shrouded in secrecy: "grey-green plain
vans", "hush-hush", "B. B. C. secret apparatus".

Was it commercial-in-confidence (not wanting to give away too many
secrets to TV companies from other countries) or was it secret in the
sense of Official Secrets Act or Defence of the Realm Act?

Or was "secret" a bit of OTT hype, referring to "not a lot of people
know that" technology? I reckon that's what it is, because the article explains that the camera, the "uplink" to the studio and the backup PSU
are contained in the vans, so they aren't keeping it secret to that extent.

The equipment cost -u4000. That's about -u242,000 in modern prices,
according to https://www.bankofengland.co.uk/monetary-policy/inflation/inflation-calculator . I'd have thought that might be quite low for broadcast-quality camera
and lens, satellite uplink, generator/battery, sound-mixing desk that
might be found in a modern scanner van
--- Synchronet 3.22a-Linux NewsLink 1.2