TV Transmitter hardware

[Brian Gaff]

I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

[Woody]

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

IMSMC high power mains stations now use a 'valve' type unit by a US
company known as Greenleaf, medium power sites are NEC (or R&S?), and
low power relays use a single unit all-in-one receiver/transmitter
transposer the manufacturer of which escapes me ATM..

Mind you I retired in 2013 so it may have changed by now!

[Brian Gaff]

Hmm, I guess there must be a reason why direct Satellite transmission tends
to still use travelling wave tubes. I'd imagine high power semiconductors
could be rather more fragile.
Brian
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Post by Woody

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

IMSMC high power mains stations now use a 'valve' type unit by a US
company known as Greenleaf, medium power sites are NEC (or R&S?), and low
power relays use a single unit all-in-one receiver/transmitter transposer
the manufacturer of which escapes me ATM..
Mind you I retired in 2013 so it may have changed by now!

[Scott]

On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite transmission tends
to still use travelling wave tubes. I'd imagine high power semiconductors
could be rather more fragile.

Could valves work better in space than they do here because space is a
natural vacuum?

[Davey]

On Mon, 23 Oct 2023 10:56:47 +0100

Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite
transmission tends to still use travelling wave tubes. I'd imagine
high power semiconductors could be rather more fragile.

Could valves work better in space than they do here because space is a
natural vacuum?

And you could even break the glass and they would still work!

[Jeff Gaines]

Post by Davey
On Mon, 23 Oct 2023 10:56:47 +0100

Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite
transmission tends to still use travelling wave tubes. I'd imagine
high power semiconductors could be rather more fragile.

Could valves work better in space than they do here because space is a
natural vacuum?

And you could even break the glass and they would still work!

That would be an interesting experiment for the ISS :-)

[Scott]

Post by Jeff Gaines

Post by Davey
On Mon, 23 Oct 2023 10:56:47 +0100

Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite
transmission tends to still use travelling wave tubes. I'd imagine
high power semiconductors could be rather more fragile.

Could valves work better in space than they do here because space is a
natural vacuum?

And you could even break the glass and they would still work!

That would be an interesting experiment for the ISS :-)

Indeed, do they need to be enclosed in glass at all? Is there scope
for a bit of weight saving?

[Davey]

On Mon, 23 Oct 2023 12:36:12 +0100

Post by Scott

Post by Jeff Gaines

Post by Davey
On Mon, 23 Oct 2023 10:56:47 +0100

Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite
transmission tends to still use travelling wave tubes. I'd
imagine high power semiconductors could be rather more fragile.

Could valves work better in space than they do here because space
is a natural vacuum?

And you could even break the glass and they would still work!

That would be an interesting experiment for the ISS :-)

Indeed, do they need to be enclosed in glass at all? Is there scope
for a bit of weight saving?

But you have to keep them sealed to get them up there. Maybe a big
overall container.
What happens to the heat generated, though?

[Scott]

Post by Davey
On Mon, 23 Oct 2023 12:36:12 +0100

Post by Scott

Post by Jeff Gaines

Post by Davey
On Mon, 23 Oct 2023 10:56:47 +0100

Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite
transmission tends to still use travelling wave tubes. I'd
imagine high power semiconductors could be rather more fragile.

Could valves work better in space than they do here because space
is a natural vacuum?

And you could even break the glass and they would still work!

That would be an interesting experiment for the ISS :-)

Indeed, do they need to be enclosed in glass at all? Is there scope
for a bit of weight saving?

But you have to keep them sealed to get them up there. Maybe a big
overall container.
What happens to the heat

I thought the whole of space would be an adequate heatsink :-)

[Tweed]

Post by Scott

Post by Davey
On Mon, 23 Oct 2023 12:36:12 +0100

Post by Scott

Post by Jeff Gaines

Post by Davey
On Mon, 23 Oct 2023 10:56:47 +0100

Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite
transmission tends to still use travelling wave tubes. I'd
imagine high power semiconductors could be rather more fragile.

Could valves work better in space than they do here because space
is a natural vacuum?

And you could even break the glass and they would still work!

That would be an interesting experiment for the ISS :-)

Indeed, do they need to be enclosed in glass at all? Is there scope
for a bit of weight saving?

But you have to keep them sealed to get them up there. Maybe a big
overall container.
What happens to the heat

I thought the whole of space would be an adequate heatsink :-)

Space electronics always needs a conduction path to some sort of radiator.
It’s usual to try to point the radiator into deep space, away from either
the sun or earth (or any other planet near by). It can be a tricky balance
between keeping the components either too hot or too cold.

[David Woolley]

I thought the whole of space would be an adequate heatsink 😄

Conduction and convection don't work in space, so you only have
radiation. And, for spacecraft one has to consider the big radiant heat
source about 93 million miles away. Thermal management of satellites is
not e

[Scott]

On Mon, 23 Oct 2023 14:26:16 +0100, David Woolley

Post by David Woolley

I thought the whole of space would be an adequate heatsink ?

Conduction and convection don't work in space, so you only have
radiation. And, for spacecraft one has to consider the big radiant heat
source about 93 million miles away. Thermal management of satellites is
not easy.

I'll stick with the day job then!

[Tweed]

Post by David Woolley

I thought the whole of space would be an adequate heatsink 😄

Conduction and convection don't work in space, so you only have
radiation. And, for spacecraft one has to consider the big radiant heat
source about 93 million miles away. Thermal management of satellites is
not easy.

Conduction from electronic assemblies to radiators is standard, either
through straps, via structure or exotically using heat pipes that only work
under zero gravity and are hard to test. I have some of my work on the way
to Mercury at the moment.

[David Woolley]

Post by Tweed
Conduction from electronic assemblies to radiators is standard, either
through straps, via structure or exotically using heat pipes that only work
under zero gravity and are hard to test. I have some of my work on the way
to Mercury at the moment.

That's in the spacecraft, not in space! Maybe it would have been
clearer if I had said "in a vacuum".

[Tweed]

Post by David Woolley

Post by Tweed
Conduction from electronic assemblies to radiators is standard, either
through straps, via structure or exotically using heat pipes that only work
under zero gravity and are hard to test. I have some of my work on the way
to Mercury at the moment.

That's in the spacecraft, not in space! Maybe it would have been
clearer if I had said "in a vacuum".

I think we are both suffering from some ambiguity here. The point I was
trying to make is spacecraft electronics are routinely cooled via
conduction - it’s practically the only method. Disposing of that heat, as
you rightly point out, has to be done by radiation. At least there are no
fan bearings to wear out….

[Jeff Gaines]

Post by Tweed
Conduction from electronic assemblies to radiators is standard, either
through straps, via structure or exotically using heat pipes that only work
under zero gravity and are hard to test. I have some of my work on the way
to Mercury at the moment.

That's in the spacecraft, not in space! Maybe it would have been clearer
if I had said "in a vacuum".

You just hold it outside the window :-)

[Brian Gaff]

No, that would not be the reason, but they are certainly better able to cope
with overloads and the like, but of course the device would still need to be
cooled.
Brian
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Post by Scott
On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite transmission tends
to still use travelling wave tubes. I'd imagine high power semiconductors
could be rather more fragile.

Could valves work better in space than they do here because space is a
natural vacuum?

[David Woolley]

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite transmission tends
to still use travelling wave tubes. I'd imagine high power semiconductors
could be rather more fragile.

I imagine that they are much less easily damaged by radiation.

[Brian Gaff]

Yes that is a thought, as at that height they are in the full solar wind,
low earth orbits can be much less of a problem but of course not
geosynchronous.
Brian
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Post by David Woolley

Post by Brian Gaff
Hmm, I guess there must be a reason why direct Satellite transmission tends
to still use travelling wave tubes. I'd imagine high power
semiconductors
could be rather more fragile.

I imagine that they are much less easily damaged by radiation.

[tony sayer]

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

Last time i looked at Sandy heath they were using the Paragon series
transmitters, these use an Inductive Output Tube (IOT) a sort of mini
Klystron or klystrode!..

https://en.wikipedia.org/wiki/Inductive_output_tube



https://www.hitachi-kokusai.co.jp/global/en/products/broadcast/trans/tv/
dcx_paragon/index.html

[Mark Carver]

Post by tony sayer

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

Last time i looked at Sandy heath they were using the Paragon series
transmitters, these use an Inductive Output Tube (IOT) a sort of mini
Klystron or klystrode!..

Comark IOTs at the highest power sites such as Belmont, Caldbeck,
Caradon, CP, Emley Moor PSB's, Rowridge PSB's, Sandy Heath PSB's, Sutton
Coldfield.

NEC DTU-52 at Beacon Hill, Black Hill, Blaenplwyf, Brougher Mountain,
Caldbeck Scotland, Carmel, Craigkelly, Darvel, Divis, Dover, Eitshal,
Hannington, Oxford, Rowridge COM's, Sandy Heath COM's, Tacolneston &
Winter Hill.

NEC DTU-10 at Angus, Bluebell Hill, Bressay, Cambret Hill, Chatton,
Fremont Point, Heathfield & Knock More.

[tony sayer]

Post by Mark Carver

Post by tony sayer

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

Last time i looked at Sandy heath they were using the Paragon series
transmitters, these use an Inductive Output Tube (IOT) a sort of mini
Klystron or klystrode!..

Comark IOTs at the highest power sites such as Belmont, Caldbeck,
Caradon, CP, Emley Moor PSB's, Rowridge PSB's, Sandy Heath PSB's, Sutton
Coldfield.
NEC DTU-52 at Beacon Hill, Black Hill, Blaenplwyf, Brougher Mountain,
Caldbeck Scotland, Carmel, Craigkelly, Darvel, Divis, Dover, Eitshal,
Hannington, Oxford, Rowridge COM's, Sandy Heath COM's, Tacolneston &
Winter Hill.
NEC DTU-10 at Angus, Bluebell Hill, Bressay, Cambret Hill, Chatton,
Fremont Point, Heathfield & Knock More.

I stand updated! Pity we can't or don't make them anymore, used to work
at Pye TVT many years ago now but UK manufacturing industry ain't wot we
do much of now:(

Makes we wonder if our Mark a has gone to work for Arqiva knowing all
that???

[Woody]

Post by tony sayer

Post by Mark Carver

Post by tony sayer

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being digital
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

Last time i looked at Sandy heath they were using the Paragon series
transmitters, these use an Inductive Output Tube (IOT) a sort of mini
Klystron or klystrode!..

Comark IOTs at the highest power sites such as Belmont, Caldbeck,
Caradon, CP, Emley Moor PSB's, Rowridge PSB's, Sandy Heath PSB's, Sutton
Coldfield.
NEC DTU-52 at Beacon Hill, Black Hill, Blaenplwyf, Brougher Mountain,
Caldbeck Scotland, Carmel, Craigkelly, Darvel, Divis, Dover, Eitshal,
Hannington, Oxford, Rowridge COM's, Sandy Heath COM's, Tacolneston &
Winter Hill.
NEC DTU-10 at Angus, Bluebell Hill, Bressay, Cambret Hill, Chatton,
Fremont Point, Heathfield & Knock More.

I stand updated! Pity we can't or don't make them anymore, used to work
at Pye TVT many years ago now but UK manufacturing industry ain't wot we
do much of now:(
Makes we wonder if our Mark a has gone to work for Arqiva knowing all
that???

No Tony, I started it by replying to Brian G and I worked for Arqiva (or
NTL as it then was) when NTL bought the service dept of Philips RCS (as
was Pye Telecom before that) in 1999.

I do wonder about Mark sometimes though!

You weren't a Pye (group) trainee in the late 60's/early 70's were you?

[tony sayer]

Post by Brian Gaff

Post by tony sayer

Post by Mark Carver

Post by tony sayer

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being

digital

Post by tony sayer

Post by Mark Carver

Post by tony sayer

Post by Brian Gaff
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

Last time i looked at Sandy heath they were using the Paragon series
transmitters, these use an Inductive Output Tube (IOT) a sort of mini
Klystron or klystrode!..

Comark IOTs at the highest power sites such as Belmont, Caldbeck,
Caradon, CP, Emley Moor PSB's, Rowridge PSB's, Sandy Heath PSB's, Sutton
Coldfield.
NEC DTU-52 at Beacon Hill, Black Hill, Blaenplwyf, Brougher Mountain,
Caldbeck Scotland, Carmel, Craigkelly, Darvel, Divis, Dover, Eitshal,
Hannington, Oxford, Rowridge COM's, Sandy Heath COM's, Tacolneston &
Winter Hill.
NEC DTU-10 at Angus, Bluebell Hill, Bressay, Cambret Hill, Chatton,
Fremont Point, Heathfield & Knock More.

I stand updated! Pity we can't or don't make them anymore, used to work
at Pye TVT many years ago now but UK manufacturing industry ain't wot we
do much of now:(
Makes we wonder if our Mark a has gone to work for Arqiva knowing all
that???

No Tony, I started it by replying to Brian G and I worked for Arqiva (or
NTL as it then was) when NTL bought the service dept of Philips RCS (as
was Pye Telecom before that) in 1999.
I do wonder about Mark sometimes though!
You weren't a Pye (group) trainee in the late 60's/early 70's were you?

I started work at Pye TvT in Coldhams lane Cambridge in around 1968 or
maybe 9! Worked on UHF 2 and UHF 77 'mitters mainly assembly and wiring
and did a little test work towards the end!

Worked on the last 405 line transmitter for ITV London at Croydon was
told that as i seemed to be the only one here who could read and
understand RF circuit diagrams was told to put indent markers on all the
components in the pen and output stages, nice to be told that by George
Hickson my foreman!

Best afternoon of the week was Friday George and the others would be
down the Rosemary branch and afterwards George would be arguing Irish
politics until manny Shelton the works MD calmed him down a bit!

Was then offered a job running the repair section of a local TV shop
great fun there had to help the aerial rigger one day was up on this
four story house and he had a collapsed lung had to put him over my
shoulder fireman fashion and carry the poor sod to the ground apart from
almost crapping myself there wasn't anyone nearby who had a phone to
call an ambulance. The next bloke was driving out with him one day and
he started shuddering and was having an epileptic attack had to pull the
poxy old vans handbrake and steer it into the verge as were we're going
downhill towards a main road!..

Started a firm dealing in Two way radio but that demised in the time of
the pandemic least wide area did..

These supposed retirement days see me assembling and planning Small
scale DAB transmitters and looking after a few commercial radio station
relays, much less boring than playing Golf:)..

[Woody]

Post by tony sayer

Post by Brian Gaff

Post by tony sayer

Post by Mark Carver

Post by tony sayer

Post by Brian Gaff
I was wondering that since digital, if the hardware has changed transmitter
side? By that I mean what sort of devices are used to generate the powers
needed at the Aerial?
Many moons ago it was your basic valve technology that they used, but have
they by now managed to get something more efficient? After all being

digital

Post by tony sayer

Post by Mark Carver

Post by tony sayer

Post by Brian Gaff
would increase the work done. Old Analogue tvs output was higher on some
scenes than others, but multiplexing several channels gets much closer to
always changing modulation at high power, one would imagine.
Brian

Last time i looked at Sandy heath they were using the Paragon series
transmitters, these use an Inductive Output Tube (IOT) a sort of mini
Klystron or klystrode!..

Comark IOTs at the highest power sites such as Belmont, Caldbeck,
Caradon, CP, Emley Moor PSB's, Rowridge PSB's, Sandy Heath PSB's, Sutton
Coldfield.
NEC DTU-52 at Beacon Hill, Black Hill, Blaenplwyf, Brougher Mountain,
Caldbeck Scotland, Carmel, Craigkelly, Darvel, Divis, Dover, Eitshal,
Hannington, Oxford, Rowridge COM's, Sandy Heath COM's, Tacolneston &
Winter Hill.
NEC DTU-10 at Angus, Bluebell Hill, Bressay, Cambret Hill, Chatton,
Fremont Point, Heathfield & Knock More.

I stand updated! Pity we can't or don't make them anymore, used to work
at Pye TVT many years ago now but UK manufacturing industry ain't wot we
do much of now:(
Makes we wonder if our Mark a has gone to work for Arqiva knowing all
that???

No Tony, I started it by replying to Brian G and I worked for Arqiva (or
NTL as it then was) when NTL bought the service dept of Philips RCS (as
was Pye Telecom before that) in 1999.
I do wonder about Mark sometimes though!
You weren't a Pye (group) trainee in the late 60's/early 70's were you?

I started work at Pye TvT in Coldhams lane Cambridge in around 1968 or
maybe 9! Worked on UHF 2 and UHF 77 'mitters mainly assembly and wiring
and did a little test work towards the end!
Worked on the last 405 line transmitter for ITV London at Croydon was
told that as i seemed to be the only one here who could read and
understand RF circuit diagrams was told to put indent markers on all the
components in the pen and output stages, nice to be told that by George
Hickson my foreman!
Best afternoon of the week was Friday George and the others would be
down the Rosemary branch and afterwards George would be arguing Irish
politics until manny Shelton the works MD calmed him down a bit!
Was then offered a job running the repair section of a local TV shop
great fun there had to help the aerial rigger one day was up on this
four story house and he had a collapsed lung had to put him over my
shoulder fireman fashion and carry the poor sod to the ground apart from
almost crapping myself there wasn't anyone nearby who had a phone to
call an ambulance. The next bloke was driving out with him one day and
he started shuddering and was having an epileptic attack had to pull the
poxy old vans handbrake and steer it into the verge as were we're going
downhill towards a main road!..
Started a firm dealing in Two way radio but that demised in the time of
the pandemic least wide area did..
These supposed retirement days see me assembling and planning Small
scale DAB transmitters and looking after a few commercial radio station
relays, much less boring than playing Golf:)..

One of my fellow trainees was a chap called Phil King. Not sure if he
was TVT or Unicam but ISTR he ended up as MD!

[tony sayer]

Post by Woody

Post by tony sayer
These supposed retirement days see me assembling and planning Small
scale DAB transmitters and looking after a few commercial radio station
relays, much less boring than playing Golf:)..

One of my fellow trainees was a chap called Phil King. Not sure if he
was TVT or Unicam but ISTR he ended up as MD!

Don't recall anyone of that name, but then again this was all a long
time ago now!..

Interesting site:)

https://www.pye-story.org/companies/pye-tvt-story/transmitters

[Mark Carver]

Post by tony sayer
Makes we wonder if our Mark a has gone to work for Arqiva knowing all
that???

Ha, no, I'm winding down these days. Too busy being a grandad !

[tony sayer]

Post by Mark Carver

Post by tony sayer
Makes we wonder if our Mark a has gone to work for Arqiva knowing all
that???

Ha, no, I'm winding down these days. Too busy being a grandad !

Since becoming a Granddad I'm winding up! Least the nippers are good at
that! Bless 'em!...