Terrestrial Switchoff - sorry to labour the point but...

On Fri, 22 Mar 2013 02:13:12 +0000, Bill Wright
wrote:

Max Demian wrote:

Isn't that what set-top rabbit ears are for?

Yes but modern sets radiate more RF than the old ones!

Bill

True, but modern sets don't suffer from corona discharge from the EHT.
(remember the white vertical 'rope' interference on Band I)

--
Graham.

%Profound_observation%

Ian Jackson wrote:

Do any DTV TV sets or STBs tune to Band 1? I think they start much
higher (off the top of my head, around 130MHz?). If so, that's another
reason for not using Band 1 for digital.

We'd just need another chuffing set top box.

Bill

In article ,
Andy Wade wrote:
On 21/03/2013 18:58, Woody wrote:

\pedant mode on

There were five channels in Band 1 and eight channels in Band
III. They were only about 6.5MHz wide as against 8MHz used today.

\pedant mode off

A c t u a l l y , dear pedant, I think you'll find that 405-line system
A used 5 MHz channelling, or perhaps I should say 5 Mc/s.

European 625-line is (or was) System B in the VHF bands and used 7 MHz
channels, not 8. This was never used in the UK of course. 8 MHz
channelling only appears at UHF,

My memory says that Eastern Europe used a 6.5MHz sound carrier at VHF.
System D, I think.



System G for the mainland and System I
(with 6 MHz sound and originally a wider VSB) for the UK, also used in
South Africa.
and Hong Kong

--
From KT24

Using a RISC OS computer running v5.18

On 21/03/13 17:09, Peter Duncanson wrote:
"Yes Sir/Madam. I know you have an old VHF aerial on your chimney, but
it's pointing in the wrong direction. Anyway, you need a High Definition
Digital VHF aerial."

A digital aerial can catch all those 1's and 0's, but an "analogue"
aerial can't..!? Cue same marketing scam as in early 1980's with
"digital headphones" after launch of the CD player.

On Sun, 24 Mar 2013 23:26:26 +0000, Ar wrote:

On 21/03/13 17:09, Peter Duncanson wrote:
"Yes Sir/Madam. I know you have an old VHF aerial on your chimney, but
it's pointing in the wrong direction. Anyway, you need a High Definition
Digital VHF aerial."

A digital aerial can catch all those 1's and 0's, but an "analogue"
aerial can't..!? Cue same marketing scam as in early 1980's with
"digital headphones" after launch of the CD player.

Somewhere I have a pair of headphones with "laser" in the name. They do
not send beams of light into the ears!

--
Peter Duncanson
(in uk.tech.digital-tv)

On 24/03/2013 23:26, Ar wrote:
On 21/03/13 17:09, Peter Duncanson wrote:
"Yes Sir/Madam. I know you have an old VHF aerial on your chimney, but
it's pointing in the wrong direction. Anyway, you need a High Definition
Digital VHF aerial."

A digital aerial can catch all those 1's and 0's, but an "analogue"
aerial can't..!? Cue same marketing scam as in early 1980's with
"digital headphones" after launch of the CD player.

Generally designed to make the most of the improved HF performance of CD
players after the dull sound of cassettes. They did this by making the
HF even louder than it was on the already top heavy CD.

Painful, most of them were.

--
Tciao for Now!

John.

On 3/25/13 12:26 AM, Ar wrote:
On 21/03/13 17:09, Peter Duncanson wrote:
"Yes Sir/Madam. I know you have an old VHF aerial on your chimney, but
it's pointing in the wrong direction. Anyway, you need a High Definition
Digital VHF aerial."

A digital aerial can catch all those 1's and 0's, but an "analogue"
aerial can't..!? Cue same marketing scam as in early 1980's with
"digital headphones" after launch of the CD player.

My uncle was offered a 'color aerial' decades back. And yes, we
continentals had color on VHF ;-)

gr, hwh

I am not aware that CDs are in any way top-heavy.

If recorded faithfully without any digital processing (which is
important to specify because digital processing is widespread), they
should have the same FR as the original sound, up to their cut-off
point of 22kHz. However, when processing is applied, it usually seems
to be either designed to boost the bass (not the treble) end, and/or
squash the dynamic range to achieve more instant 'impact'.

I think what may be going on here is that many previous analogue
systems were top-light. For example, IMS the top end of AC is limited
by the slow tape speed to about 16kHz or so, that of a Shure VIII
vinyl cartridge is around 20kHz, and although a good consumer
open-reel tape system at its fastest tape speed (19cm/s) could match a
CD's FR, it could never begin to approach its SN ratio, say 45dB as
opposed to 100dB. This significantly higher SN ratio of CDs also
allows one to hear fainter, higher transients in the sound that used
to be swamped by vinyl noise or tape hiss.

Thus, to someone used to an analogue sound, a CD at first hearing
seemed unusually bright in the treble, though one's ear adjusted
fairly quickly, after which, going back to the analogue source can be
almost painful. But, in the absence of processing (always
remembering), it's the CD that has the authentic sound - that is the
sound closest to what was actually recorded - not the analogue
systems.

On Mon, 25 Mar 2013 15:20:09 +0000, John Williamson
wrote:

the already top heavy CD.
--
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"Ian Jackson" wrote in message
...
In message , Stephen
writes

If they sold off the whole of UHF, we could go back using VHF for TV if we
just forgot about the regional news. Freeview only needs 6 channels for
single frequency networks and these 6 should be available on VHF Bands I
and III.

Only the regional TV variations need to be relegated to satellite, cable &
internet.

The VHF bands are much less attractive to mobile phone operators because
of the much longer aerials required (particularly for Band I) but they are
perfectly good for terrestrial TV, and a new VHF TV aerial would be
cheaper than a dish, and much easier to align. We might return to the days
of H
aerials, X aerials and Band III Yagis, but with digital TV on VHF instead
of 405 lines.

There are only eight or nine 8MHz VHF TV channels available (3 in Band 1
and 6 or 7 in Band 3) - and it would be extremely difficult
comprehensively to provide the whole of UK with 6 digital MUXes in the
same way as the two analogue channels were provided. At best, the full 6
MUXes could probably only be provided in well-separated centres of large
populations.

I don't think this is the case. They should be able to use the same 6
channels at all transmitters like National DAB. A VHF network for Freeview
could be designed alongside an upgrade to DAB/DAB+, using the same
transmitting aerials and the same transmitter sites.

It may only need 5 multiplexes as there would be no need to duplicate the 4
main channels (BBC1 HD etc) in Standard Definition as is done at present. No
duplication of DAB radio on Freeview VHF would save some more space. The
system could use the European 7 MHz channel standard to integrate with DAB
which uses the same standard.

It might work out something like this: Channels E6, 7, 8, 9, 10 for DVB-T2,
and Channels E5, 11, 12, 13, 14 for DAB+.

In message , Stephen
writes

"Ian Jackson" wrote in message
...
In message , Stephen
writes

If they sold off the whole of UHF, we could go back using VHF for TV if we
just forgot about the regional news. Freeview only needs 6 channels for
single frequency networks and these 6 should be available on VHF Bands I
and III.

Only the regional TV variations need to be relegated to satellite, cable &
internet.

The VHF bands are much less attractive to mobile phone operators because
of the much longer aerials required (particularly for Band I) but they are
perfectly good for terrestrial TV, and a new VHF TV aerial would be
cheaper than a dish, and much easier to align. We might return to the days
of H
aerials, X aerials and Band III Yagis, but with digital TV on VHF instead
of 405 lines.

There are only eight or nine 8MHz VHF TV channels available (3 in Band 1
and 6 or 7 in Band 3) - and it would be extremely difficult
comprehensively to provide the whole of UK with 6 digital MUXes in the
same way as the two analogue channels were provided. At best, the full 6
MUXes could probably only be provided in well-separated centres of large
populations.

I don't think this is the case. They should be able to use the same 6
channels at all transmitters like National DAB. A VHF network for Freeview
could be designed alongside an upgrade to DAB/DAB+, using the same
transmitting aerials and the same transmitter sites.

It may only need 5 multiplexes as there would be no need to duplicate the 4
main channels (BBC1 HD etc) in Standard Definition as is done at present. No
duplication of DAB radio on Freeview VHF would save some more space. The
system could use the European 7 MHz channel standard to integrate with DAB
which uses the same standard.

It might work out something like this: Channels E6, 7, 8, 9, 10 for DVB-T2,
and Channels E5, 11, 12, 13, 14 for DAB+.

Because of the need to prevent co-channel interference, it took five
Band 1 and eight Band 3 channels to provide two nationally-available
405-line analogue channels. OK, digital may be more resistant to the
effects of co-channel, but it seems extremely optimistic that five
adjacent channels at the bottom end of Band 3 could provide five MUXes
nationally. If it were possible, surely they would already be doing this
in Band 4 (say channels 21 to 25), leaving the rest of Bands 4 and 5 for
'other things'?
--
Ian