Well, perhaps Ofcom were lurking in here over Christmas :-)


Ofcom has today published updated versions of its regional Digital
Switchover Transmitter Details documents, which can be downloaded from

http://stakeholders.ofcom.org.uk/bro...ce/dsodetails/.

The Document History provided at the end of each document contains
details of the main changes since the previous version.

On 05/01/2011 11:36, Mark Carver wrote:
Well, perhaps Ofcom were lurking in here over Christmas :-)


Ofcom has today published updated versions of its regional Digital
Switchover Transmitter Details documents, which can be downloaded from

http://stakeholders.ofcom.org.uk/bro...ce/dsodetails/.


The Document History provided at the end of each document contains
details of the main changes since the previous version.

Thanks for the link.

Out of interest, do you happen to know what is the reason why the
commercial multiplexes are often at only half the ERP of the PSB ones?
I see that at the end of the pdf it states "some channels may need to
operate at slightly reduced power levels compared to the final
post-switchover allocations shown in this booklet.". But half power is
hardly "slightly reduced", and why is it always the commercial mux which
is reduced?

--

Jeff

Jeff Layman wrote:

Out of interest, do you happen to know what is the reason why the
commercial multiplexes are often at only half the ERP of the PSB ones? I
see that at the end of the pdf it states "some channels may need to
operate at slightly reduced power levels compared to the final
post-switchover allocations shown in this booklet.". But half power is
hardly "slightly reduced", and why is it always the commercial mux which
is reduced?

At many sites the COM muxes are using allocations that have a lower
power clearance (for international frequency planning reasons) than the
PSBs.

Remember, in most cases, the PSB muxes are using three out of four of
the old analogue allocations. The Chester 1997 agreement stated that an
analogue channel could be reused for a DTT mux with a 7dB decrease in
power (comparing 'peak sync' for analogue, with 'mean' for COFDM).

That's why generally the post DSO PSB muxes are about a fifth
(or -7dB) of the old analogue power levels.

However COM power levels are 10db lower in many cases. They are on 'new'
allocations, where the international agreements may differ and/or are
tighter.

They are not really significanly lower than the PSBs, half the power is
only a difference of 3dB.

On 5 Jan., 18:17, Mark Carver wrote:

Remember, in most cases, the PSB muxes are using three out of four of
the old analogue allocations. The Chester 1997 agreement stated that an
analogue channel could be reused for a DTT mux with a 7dB decrease in
power (comparing 'peak sync' for analogue, with 'mean' for COFDM).

The GE06 is a new agreement - the
ST61 (and Chester 1997) agreements are
no longer valid for UHF and VHF III (june 2015).
The old ST61 allocations are in no way moved
into the GE06 agreement.
Everything in GE06 is based on a 'blank sheet of paper'
and 100% new requests from each country.

Ofcom happend to ask for some of the 'old'
channel numbers in Geneva 2006* - and was
in many cases succesful in getting them.

But all arguments of the type "we can reuse the
analogue channels for dtt" are not valid.

They are not really significanly lower than the PSBs, half the power is
only a difference of 3dB.

Agreed, unless some additional directional
reductions is used for the COM channels only.

Lars

PS! The GE06 was a multiyear proccess ending in 2006.

reslfj wrote:
On 5 Jan., 18:17, Mark Carver wrote:
Remember, in most cases, the PSB muxes are using three out of four of
the old analogue allocations. The Chester 1997 agreement stated that an
analogue channel could be reused for a DTT mux with a 7dB decrease in
power (comparing 'peak sync' for analogue, with 'mean' for COFDM).

The GE06 is a new agreement - the
ST61 (and Chester 1997) agreements are
no longer valid for UHF and VHF III (june 2015).
The old ST61 allocations are in no way moved
into the GE06 agreement.
Everything in GE06 is based on a 'blank sheet of paper'
and 100% new requests from each country.

Ofcom happend to ask for some of the 'old'
channel numbers in Geneva 2006* - and was
in many cases succesful in getting them.

Thanks for clarifying Lars, AIUI they did that so that post DSO the PSB muxes
would still be on three of the four 'Stockholm 1961' allocations, the logic
being that any communal aerial system filtering for analogue reception won't
need adjustment to pass the PSB muxes, plus of course the wider advantage of
keeping everything in the legacy aerial groups.

If you look at the post DSO tables, the vast majority of PSB allocations are
still on legacy Stockholm allocations.


But all arguments of the type "we can reuse the
analogue channels for dtt" are not valid.

They are not really significanly lower than the PSBs, half the power is
only a difference of 3dB.

Agreed, unless some additional directional
reductions is used for the COM channels only.

Yes, good point. Of course directional restriction data is bizarrely kept out
of the public domain (other than by reverse engineering by selecting postcodes
and sticking them in the DUK checker). Mustn't make things too easy for
riggers it seems.

--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

On Wed, 05 Jan 2011 17:17:11 +0000, Mark Carver
wrote:

Jeff Layman wrote:

Out of interest, do you happen to know what is the reason why the
commercial multiplexes are often at only half the ERP of the PSB ones? I
see that at the end of the pdf it states "some channels may need to
operate at slightly reduced power levels compared to the final
post-switchover allocations shown in this booklet.". But half power is
hardly "slightly reduced", and why is it always the commercial mux which
is reduced?

At many sites the COM muxes are using allocations that have a lower
power clearance (for international frequency planning reasons) than the
PSBs.

How far does UHF travel? I can understand that there would be
problems in Kent or Essex but in Scotland you must be thousands of
miles from anywhere. Is foreign interference a serious issue?

Or thinking about it do the power restrictions depend on where the
transmitter is located in the UK?

On Wed, 05 Jan 2011 17:03:51 +0000, Jeff Layman
wrote:

On 05/01/2011 11:36, Mark Carver wrote:
Well, perhaps Ofcom were lurking in here over Christmas :-)


Ofcom has today published updated versions of its regional Digital
Switchover Transmitter Details documents, which can be downloaded from

http://stakeholders.ofcom.org.uk/bro...ce/dsodetails/.


The Document History provided at the end of each document contains
details of the main changes since the previous version.

Thanks for the link.

Out of interest, do you happen to know what is the reason why the
commercial multiplexes are often at only half the ERP of the PSB ones?
I see that at the end of the pdf it states "some channels may need to
operate at slightly reduced power levels compared to the final
post-switchover allocations shown in this booklet.". But half power is
hardly "slightly reduced", and why is it always the commercial mux which
is reduced?

None of that nonsense here - one hundred thousand watts for every
multiplex. Over half a million watts in total. Jeremy Clarkson will
be impressed !!!

In article ,
Scott wrote:
On Wed, 05 Jan 2011 17:17:11 +0000, Mark Carver
wrote:

Jeff Layman wrote:

Out of interest, do you happen to know what is the reason why the
commercial multiplexes are often at only half the ERP of the PSB ones?
I see that at the end of the pdf it states "some channels may need to
operate at slightly reduced power levels compared to the final
post-switchover allocations shown in this booklet.". But half power is
hardly "slightly reduced", and why is it always the commercial mux
which is reduced?

At many sites the COM muxes are using allocations that have a lower
power clearance (for international frequency planning reasons) than the
PSBs.

How far does UHF travel? I can understand that there would be
problems in Kent or Essex but in Scotland you must be thousands of
miles from anywhere.

The nearest railway station to Shetland is in Norway!
and Ireland is quite close too.

Is foreign interference a serious issue?

Or thinking about it do the power restrictions depend on where the
transmitter is located in the UK?

--
From KT24

Using a RISC OS computer running v5.16

On Thu, 06 Jan 2011 18:09:25 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
On Wed, 05 Jan 2011 17:17:11 +0000, Mark Carver
wrote:

Jeff Layman wrote:

Out of interest, do you happen to know what is the reason why the
commercial multiplexes are often at only half the ERP of the PSB ones?
I see that at the end of the pdf it states "some channels may need to
operate at slightly reduced power levels compared to the final
post-switchover allocations shown in this booklet.". But half power is
hardly "slightly reduced", and why is it always the commercial mux
which is reduced?

At many sites the COM muxes are using allocations that have a lower
power clearance (for international frequency planning reasons) than the
PSBs.

How far does UHF travel? I can understand that there would be
problems in Kent or Essex but in Scotland you must be thousands of
miles from anywhere.

The nearest railway station to Shetland is in Norway!
and Ireland is quite close too.

Most of Scotland is rather further from Norway.

Northern Ireland is of course part of the UK, so any 'international'
planning would only affect ROI which is quite a distance from Scotland
(and even further from Shetland).

Is foreign interference a serious issue?

Or thinking about it do the power restrictions depend on where the
transmitter is located in the UK?

My question was whether the restrictions are specific to each
transmitter site or if there global restrictions for all sites, which
would seem unnecessary in many cases.

In article ,


Northern Ireland is of course part of the UK, so any 'international'
planning would only affect ROI which is quite a distance from Scotland
(and even further from Shetland).


A quick look at a map will show the ROI is only about 40 miles from
Scotland at the nearest point


My question was whether the restrictions are specific to each
transmitter site or if there global restrictions for all sites, which
would seem unnecessary in many cases.

but you also said: "in Scotland you must be thousands of miles from
anywhere."

--
From KT24

Using a RISC OS computer running v5.16