The Wrekin overnight 18th-20th January tests will affect Sutton Coldfield
Brian Butterworth published on UK Free TV An essential part of the tests on the new aerials at The Wrekin transmitter - so they will function correctly on switchover day, 20th April 2011 - full power overnight testing is done.
During the test, all the existing Freeview services will remain on air.
However, the analogue services will be switched off as follows:
Tuesday 18th January: BBC ONE, BBC TWO from 0020 (plus ITV1, Channel 4 and FIVE).
Wednesday 19th January: BBC ONE from 0110, BBC TWO from 0010 (plus ITV1, Channel 4 and FIVE).
Thursday 20th January: BBC ONE from 0150, BBC TWO from 0010 (plus ITV1, Channel 4 and FIVE).
Because the commercial multiplexes will use C41, C44 and C47 at The Wrekin after switchover (and hence, during these tests) this will clash with Freeview multiplexes 1, 2 and A on the Sutton Coldfield transmitter.
This means that many Sutton Coldfield Freeview users will not have usable service overnight during the testing period.
Help with Freeview, aerials?
In this section
Wednesday, 19 January 2011
Stuart: Lark Stoke's pre-switchover digital services at at 25W, about the same as single energy-saving bulb. It is amazing that anyone gets Freeview from there at the moment.
Lark Stoke will be a 1.26kW digital transmitter after switchover, that's 50 times more powerful.
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Wutty: Sorry, I should have explained better.
After switchover there are six multiplexes broadcast - three are "public services" PSB1, PSB2 and PSB3, and three are "commercial", COM4, COM5 and COM6.
They are also known by other names. The PSBs are BBCA, D3+4, BBCB, the COMs are SDN, ARQA, ARQB.
At some transmitters the commercial multiplexes switch a few months after the official switchover, to protect the analogue services in other regions that are still broadcasting.
That's why you get the 28th September 2011 date for the "COM power up".
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Stuart: The analogue channel 5 network uses different transmitters from the normal analogue one-four network.
They are generally speaking the old ITV 405-line transmitters on UK TV Frequency map - channel C37 (602.0MHz) before switchover map | ukfree.tv - independent free digital TV advice and UK TV Frequency map - channel C35 (586.0MHz) before switchover map | ukfree.tv - independent free digital TV advice .
This means the network has different power levels and characteristics from both the analogue 1-4 network and the digital network.
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Wutty12:33 PM
Briantist - no need to apologise - The info is very useful and (now) I understand! Many thanks.
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chris1:59 PM
hi there , when the switch over is complete, and the transmitters are on full power, will there still be a limit on the maximum signal strength being recieved at the tv? for example at the moment signal strength should be between 45dbuv - 65dbuv, with the maximum being 65dbuv to stop the strength of analogue transmissions swamping the tuner....
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chris: I'm not sure how the physics could possibly do that, what with the inverse power law.
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Mike Dimmick6:55 PM
Reading
Brian:
Lark Stoke is currently a 6.3 kW transmitter according to Ofcom, and also Wolfbane's list of transmitters. I don't know where you got 25W from. It gets a reduction to one-fifth at switchover like the vast majority of sites.
25W would be very powerful for a compact fluorescent lightbulb, but very weak for a conventional incandescent. It's actually a good indication of how electromagnetic wave transmission drops off with increasing frequencies, as light is just an extremely high frequency radio wave (500 or so terahertz, one million times faster than TV signals). 25W at UHF TV frequencies can carry quite a long way - by the ITU-R estimation formula, with clear line of sight and assuming no interference or fading, you'd still get enough signal for digital TV more than 70km from the transmitter. For perfect analogue you'd have to be within 5 km as it requires so much greater signal-to-noise ratio.
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Mike's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Mike Dimmick: I'm not sure where the 25W came from exactly, I think it was from the original Ofcom/ONdigital database.
It is 6.3kW for analogue, and it would be very odd for the digital services to be at the same power as the analogue ones, as that doesn't happen normally.
Wolfbane is not a primary source, sorry.
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