The Digital Switchover is to commence this week across much of the South Coast of England, with the main transmitters at Rowridge (Isle of Wight) and Whitehawk Hill (Brighton) and associated relays to start the switch Wednesday 7th March 2012.
These transmitters cover an area stretching from Weymouth in the West (which is at the edge of the Westcountry ITV region) to Brighton in the East and include major towns and cities including Bournemouth, Salisbury, Southampton, Plymouth and Chichester. Whilst most of West Sussex started switchover last week, those parts to the South of the Downs will be affected from this week.
On Wednesday morning (7th March), viewers who receive Freeview will need to retune to restore all channels due to the BBC's services moving frequencies. BBC2 analogue is switched off for good just after midnight. During the night into the morning of Wednesday, remaining analogue and digital services will be affected and will be subject to shutdowns for several hours. Normal service should resume by 6am, but later in the day if receiving from a relay site.
The process repeats itself on 21st March, when all remaining analogue services cease, and further frequency changes take place, where many digital services will move to frequencies vacated by the analogue services, and parts of the UHF TV frequency band are cleared for use by 4G mobile internet from 2013. Again, services will be shutdown overnight for several hours (longer on relays). BBC standard definition services and radio stations on Freeview may go off air for a short time, but will return on the same frequency by morning. Viewers with Freeview HD certified equipment will be able to watch the Freeview HD service across the South Coast from the 21st March.
On the 18th April, viewers who receive direct from Rowridge directly will need to retune, as the commercial multiplexes carrying channels such as Sky News, Dave, 4Music, QVC, 5* and ITV4 move frequencies and commence transmitting a full power. Rowridge viewers have to do this additional retune, as all of Rowridge's assigned frequencies can't be used until London has completed switchover.
MORE TECHNICAL INFORMATION, INCLUDING UHF CHANNEL NUMBERS:Rowridge: http://a516.blogspot.com/2012/03/rowridge-uhf-broadcast-channels.html
Salisbury and Whitehawk Hill: http://a516.blogspot.com/2012/03/salisbury-and-whitehawk-hill-uhf.html
Digital Switchover Frequently Asked Questions: http://a516.blogspot.com/p/switchover-faq.html NEW
A few notable events occur in conjunction with the switchover along the south coast:
Dual polarisation transmissions from Rowridge - helping to reduce interference from France
Due to the proximity to France, and the fact that aerials pointing at Rowridge on the Isle of Wight are also pointing to France beyond that, there has been issues with interference from the continent. To mitigate this, dual polarisation will be used - signals will be broadcast in both horizontal and vertical polarisation.
Viewers who watch programmes from Rowridge transmitter will be able to tilt the axis of their aerials by 90 degrees, so that the rods along the aerial go from top to bottom, rather than from side to side. (Basically, aerials that birds can sit on are generally set for reception of horizontal polarised TV services - the elements are flat, whereas vertically polarised aerials are not, and unless birds can perch on the narrow points of the top ends of the elements will not find them comfortable to sit on!!!!)
Doing this will enable viewers to receive the vertically polarised service from Rowridge. Currently, all services are horizontally polarised - as are France's services. Until all services start transmitting in vertical polarisation and at full power in April, it will not be worthwhile changing the aerial, unless receiving via an indoor aerial*. Viewers who don't do anything will still be able to receive services, but some commercial services will be received at lower signal strengths and may be subject to inference from France or even Crystal Palace, London during favourable atmospheric conditions.
New relay transmitters to improve coverage of the core public service channels in Littlehampton and Worthing
Rowridge is not expected to provide completely reliable digital service across the South Coast in the direction of Sussex affecting Littlehampton and Worthing. Therefore, the existing relay at Findon will be boosted, and will transmit the basic public service channels at 40 times higher power than the previous analogue services. On the 7th, the BBC services commence transmitting at these higher powers, and then on the 21st March, ITV/C4/C5 and HD services commence. HD services require specific Freeview HD certified equipment. Households in this area may need to have their aerial installations amended so as to point to Findon, if they find Rowridge transmitter too unreliable. Commercial services will not be transmitted from Findon, as the commercial multiplex operators are not expanding their network at switchover.
Change of BBC Region in Brighton.
The Whitehawk Hill transmitter will switch BBC regions from March 7th, on the date that BBC digital services on Freeview commence on a new frequency. South Today will be replaced by South East Today. It is unknown whether the remaining analogue BBC1 service will continue to carry South Today until final switchoff on March 21st, or whether this service will be changed for its final two weeks on air.
ITV Meridian services will remain unchanged.
Change of source transmitter for Patcham and Hangleton
Viewers receiving from the relays at Patcham and Hangleton will also notice a change in their BBC region, as these relays will relay digital services from Whitehawk Hill transmitter as opposed to Rowridge transmitter, which is where the analogue services have been relayed from.
*reception via an indoor aerial only in areas close to the transmitter and especially in houses with a clear line of sight towards the Isle of Wight, or if you are on the Isle of Wight, with a clear line towards Rowridge.
The Digital UK newsletter contradicts itself. It states that all public service multiplexes from Rowridge transmitter will commence transmissions in vertical polarisation on the 21st, however the timeline for what happens on the 7th (stage 1), shows Rowridge VP - (vertical polarisation). Based on supporting information, a516_digital assumes that the BBC services will commence transmission in both horizontal and vertical polarisation on the 7th, when its services move to final post-switchover signal powers and frequencies, two weeks ahead of stage 2, when all other public service broadcasters commence on post-switchover frequencies and powers.