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

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On Sun 22/10/2023 14:40, Brian Gaff wrote:
> 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!

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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"Woody" <harrogate3@ntlworld.com> wrote in message
news:uh3b1g$2fc66$1@dont-email.me...
> On Sun 22/10/2023 14:40, Brian Gaff wrote:
>> 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!

On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
<brian1gaff@gmail.com> wrote:

>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?

On 23/10/2023 10:48, Brian Gaff wrote:
> 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.

On Mon, 23 Oct 2023 10:56:47 +0100
Scott <newsgroups@gefion.myzen.co.uk> wrote:

> On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
> <brian1gaff@gmail.com> wrote:
>
> >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!

--
Davey.

On 23/10/2023 in message <uh5jcb$335m6$1@dont-email.me> Davey wrote:

>On Mon, 23 Oct 2023 10:56:47 +0100
>Scott <newsgroups@gefion.myzen.co.uk> wrote:
>
>>On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
>><brian1gaff@gmail.com> wrote:
>>
>>>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 :-)

--
Jeff Gaines Dorset UK
Politics is the art of looking for trouble, finding it whether it exists
or not, diagnosing it incorrectly, and applying the wrong remedies.

On 23 Oct 2023 11:01:06 GMT, "Jeff Gaines" <jgnewsid@outlook.com>
wrote:

>On 23/10/2023 in message <uh5jcb$335m6$1@dont-email.me> Davey wrote:
>
>>On Mon, 23 Oct 2023 10:56:47 +0100
>>Scott <newsgroups@gefion.myzen.co.uk> wrote:
>>
>>>On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
>>><brian1gaff@gmail.com> wrote:
>>>
>>>>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?

On Mon, 23 Oct 2023 12:36:12 +0100
Scott <newsgroups@gefion.myzen.co.uk> wrote:

> On 23 Oct 2023 11:01:06 GMT, "Jeff Gaines" <jgnewsid@outlook.com>
> wrote:
>
> >On 23/10/2023 in message <uh5jcb$335m6$1@dont-email.me> Davey wrote:
> >
> >>On Mon, 23 Oct 2023 10:56:47 +0100
> >>Scott <newsgroups@gefion.myzen.co.uk> wrote:
> >>
> >>>On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
> >>><brian1gaff@gmail.com> wrote:
> >>>
> >>>>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?

--
Davey.

On Mon, 23 Oct 2023 13:49:34 +0100, Davey <davey@example.invalid>
wrote:

>On Mon, 23 Oct 2023 12:36:12 +0100
>Scott <newsgroups@gefion.myzen.co.uk> wrote:
>
>> On 23 Oct 2023 11:01:06 GMT, "Jeff Gaines" <jgnewsid@outlook.com>
>> wrote:
>>
>> >On 23/10/2023 in message <uh5jcb$335m6$1@dont-email.me> Davey wrote:
>> >
>> >>On Mon, 23 Oct 2023 10:56:47 +0100
>> >>Scott <newsgroups@gefion.myzen.co.uk> wrote:
>> >>
>> >>>On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
>> >>><brian1gaff@gmail.com> wrote:
>> >>>
>> >>>>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 :-)

Scott <newsgroups@gefion.myzen.co.uk> wrote:
> On Mon, 23 Oct 2023 13:49:34 +0100, Davey <davey@example.invalid>
> wrote:
>
>> On Mon, 23 Oct 2023 12:36:12 +0100
>> Scott <newsgroups@gefion.myzen.co.uk> wrote:
>>
>>> On 23 Oct 2023 11:01:06 GMT, "Jeff Gaines" <jgnewsid@outlook.com>
>>> wrote:
>>>
>>>> On 23/10/2023 in message <uh5jcb$335m6$1@dont-email.me> Davey wrote:
>>>>
>>>>> On Mon, 23 Oct 2023 10:56:47 +0100
>>>>> Scott <newsgroups@gefion.myzen.co.uk> wrote:
>>>>>
>>>>>> On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
>>>>>> <brian1gaff@gmail.com> wrote:
>>>>>>
>>>>>>> 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.

On 23/10/2023 13:51, Scott wrote:
> 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.

On Mon, 23 Oct 2023 14:26:16 +0100, David Woolley
<david@ex.djwhome.demon.invalid> wrote:

>On 23/10/2023 13:51, Scott wrote:
>> 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!

David Woolley <david@ex.djwhome.demon.invalid> wrote:
> On 23/10/2023 13:51, Scott wrote:
>> 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.

On 23/10/2023 15:13, Tweed wrote:
> 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".

David Woolley <david@ex.djwhome.demon.invalid> wrote:
> On 23/10/2023 15:13, Tweed wrote:
>> 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….

On 23/10/2023 in message <uh66gq$38a5h$1@dont-email.me> David Woolley wrote:

>On 23/10/2023 15:13, Tweed wrote:
>>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 :-)

--
Jeff Gaines Dorset UK
The first five days after the weekend are the hardest.

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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"Scott" <newsgroups@gefion.myzen.co.uk> wrote in message
news:bogcji5l99mroji0fnqknvug9b1e4avs95@4ax.com...
> On Mon, 23 Oct 2023 10:48:50 +0100, "Brian Gaff"
> <brian1gaff@gmail.com> wrote:
>
>>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?

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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"David Woolley" <david@ex.djwhome.demon.invalid> wrote in message
news:uh5gek$329eh$1@dont-email.me...
> On 23/10/2023 10:48, Brian Gaff wrote:
>> 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.

In article <uh38p4$2erkk$1@dont-email.me>, Brian Gaff
<brian1gaff@gmail.com> scribeth thus
>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
--
Tony Sayer

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

Give him a keyboard, and he will reveal himself.

On 04/11/2023 14:49, tony sayer wrote:
> In article <uh38p4$2erkk$1@dont-email.me>, Brian Gaff
> <brian1gaff@gmail.com> scribeth thus
>> 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.

In article <kqn4dqFlabtU1@mid.individual.net>, Mark Carver
<mark@invalid.com> scribeth thus
>On 04/11/2023 14:49, tony sayer wrote:
>> In article <uh38p4$2erkk$1@dont-email.me>, Brian Gaff
>> <brian1gaff@gmail.com> scribeth thus
>>> 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???
--
Tony Sayer

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

Give him a keyboard, and he will reveal himself.

On Tue 07/11/2023 12:29, tony sayer wrote:
> In article <kqn4dqFlabtU1@mid.individual.net>, Mark Carver
> <mark@invalid.com> scribeth thus
>> On 04/11/2023 14:49, tony sayer wrote:
>>> In article <uh38p4$2erkk$1@dont-email.me>, Brian Gaff
>>> <brian1gaff@gmail.com> scribeth thus
>>>> 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?

On 07/11/2023 12:29, tony sayer wrote:

>
> 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 !

In article <kqv5c1F32lU1@mid.individual.net>, Mark Carver
<mark@invalid.com> scribeth thus
>On 07/11/2023 12:29, tony sayer wrote:
>
>>
>> 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!...
--
Tony Sayer

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

Give him a keyboard, and he will reveal himself.