I hope you have either already retuned or will retune today all your Freeview tv receivers. That will bring in the D3&4 Mux at the full power of 200kW, so if you've previously had problems receiving stations like ITV-1, C4 and C5 you should now be watching uninterrupted pictures. Don't forget the final retune you will have to do is on 18 April, if you are receiving from Rowridge but not if you are receiving from a relay transmitter or from the Mendip transmitter. Difficulty in receiving other stations now may well be cured at that time.
If you have a high definition Freeview receiver you will now also be able to receive, for the first time via terrestrial television, the four high definition stations: BBC-1 HD, BBC HD, ITV-1 HD and C4 HD. There are two points about these high definition stations which are relevant.
1. They are being transmitted from Rowridge on channel 21. This is the lowest channel in the UHF spectrum and the one to which a Group A aerial is least sensitive. Don't be concerned, therefore, if your equipment shows slightly lower signal strength and/or quality than for the standard definition stations. It may be between 10 and 20% lower but should still provide a stable picture and sound, unless you are near the "cliff edge" for the standard definition channels. In which case you may have some problems.
2. Only BBC HD at presents transmits all high definition sourced programmes. That means they are made in high definition. Because the other three high definition stations are HD versions of their standard definition counterparts, not all their programmes will have been made in high definition. Usually the listings magazines will include the letters "HD" in their description of a programme made in high definition. If those letters are not included it indicates the programme was made in standard definition. You will need to check that your listings magazine does use that identifier.
A programme made in standard definition is upscaled prior to transmission on a high definition channel. That doesn't make it high definition but just ensures it fills your tv screen completely. Your tv does that upscaling to all the standard definition stations you tune into anyway. It makes little difference whether you use the high definition station or the standard definition station to view a standard definition programme, but it does have a significance when using a PVR (Personal Video Recorder) to record such a programme.
If you record a standard definition sourced programme from the high definition station it will take up as much space on your PVR's hard disc as if it were a true high definition programme, which is a bit of a waste of space. You might just as well record it from the standard definition station and let your tv upscale for you. That way the programme will take up only about 25% of the space on your hard disc which recording from the high definition station would have occupied, with no disadvantage in picture quality.
Wednesday, 21 March 2012
Sunday, 11 March 2012
Co-Channel Interference
The weather forecast for this week is for the high pressure over the UK to maintain and even strengthen its position. This is the "ideal" situation for co-channel (sometimes called cross-channel or pattern) interference to occur while trying to receive a television transmission. With analogue tv this shows up as a pattern of wavy or horizontal lines on the screen. With digital tv, once a threshold has been reached, you lose the Mux you're trying to watch completely.
These events are caused by a powerful tv transmitter somewhere in mainland Europe (or elsewhere in the UK) being unusually received by your aerial owing to its transmissions being reflected by the atmosphere down to your aerial. In low pressure weather conditions such transmissions go in straight lines off into space.
Some enthusiasts like to receive distant tv transmissions and their forecasts are for Tuesday to Thursday of this week achieving the peak for such reception and therefore for co-channel interference to be more likely.
If you draw a straight line on a map from Wimborne to Rowridge and extend it beyond, it goes very close to Lille in France. There lies a powerful digital tv transmitter which includes transmissions on channels 21, 24 and 27, exactly the channels used by Rowridge for its three PSB (Public Service Broadcast) Muxes. If you find this week, or at any future time, that you lose any or all of these three Muxes, that transmitter could be the problem. The solution is to have your aerial rotated through 90 degrees so it is vertically polarised. I would advise waiting until after 18 April to have that done otherwise you will lose some stations in the meantime.
These events are caused by a powerful tv transmitter somewhere in mainland Europe (or elsewhere in the UK) being unusually received by your aerial owing to its transmissions being reflected by the atmosphere down to your aerial. In low pressure weather conditions such transmissions go in straight lines off into space.
Some enthusiasts like to receive distant tv transmissions and their forecasts are for Tuesday to Thursday of this week achieving the peak for such reception and therefore for co-channel interference to be more likely.
If you draw a straight line on a map from Wimborne to Rowridge and extend it beyond, it goes very close to Lille in France. There lies a powerful digital tv transmitter which includes transmissions on channels 21, 24 and 27, exactly the channels used by Rowridge for its three PSB (Public Service Broadcast) Muxes. If you find this week, or at any future time, that you lose any or all of these three Muxes, that transmitter could be the problem. The solution is to have your aerial rotated through 90 degrees so it is vertically polarised. I would advise waiting until after 18 April to have that done otherwise you will lose some stations in the meantime.
Wednesday, 7 March 2012
DSO-1 Completed
DSO-1 is now completed and the BBC-A Mux is now being transmitted from the new Rowridge transmitter at 200 kW power in both horizontal and vertical polarisation. During the night there have been interrupts to other Muxes, causing a possible problem depending upon your equipment.
Those of you with PVRs (personal video recorders) or any other digital Freeview recording device would be advised to leave such a device fully on for at least 30 minutes and then to check the Guide or Schedule for recordings you have already set up, especially series recordings. You may find the scheduling for those recordings has been deleted and they no longer show as being bookmarked for recording. Just redo the scheduling and remember to check that again at DSO-2 on 21 March and the retune event on 18 April.
All Relay transmitters should now be on stream for the BBC A Mux for the first time.
Those of you with PVRs (personal video recorders) or any other digital Freeview recording device would be advised to leave such a device fully on for at least 30 minutes and then to check the Guide or Schedule for recordings you have already set up, especially series recordings. You may find the scheduling for those recordings has been deleted and they no longer show as being bookmarked for recording. Just redo the scheduling and remember to check that again at DSO-2 on 21 March and the retune event on 18 April.
All Relay transmitters should now be on stream for the BBC A Mux for the first time.
Tuesday, 6 March 2012
Retuning
Tomorrow, Wednesday 7 March, you will have to retune each piece of equipment which sports a Freeview terrestrial digital tuner in order to continue watching BBC stations. In addition to television sets and set-top boxes this includes PVRs (Personal Video Recorders), DVD/HDD Recorders etc. Any recordings you currently have made will not be affected by a retune (a question I'm often asked).
Unfortunately It is not possible to provide a universal set of instructions for the process of retuning which will work every time in every piece of Freeview equipment. This is because each manufacturer has produced their own individual way of setting up how it should be done, even using their own unique vocabulary for each aspect. What is possible, however, is to provide a universal strategy for tackling the process and I list that strategy below.
Strategy for the Retuning Process applied to Freeview equipment
1. Follow the instructions for retuning provided in the manual you received with each piece of equipment. If you don't have a manual, they can be downloaded from the internet at no cost. Just Google the Manufacturer's Name and Model Number followed by the word manual, eg "Panasonic TX-L32E30B manual". The equipment does not have to be currently on sale - it is still possible to download manuals for older equipment.
2. Have open at the same time pages 14 and 15 of the Digital UK booklet "Your Guide to Switchover", delivered to all homes in the area a few months ago. If you cannot find your copy there may still be some available from Wimborne Library or the Tourist Information Centre. Alternatively you could send to Digital UK for another copy: Phone: 08456 50 50 50
3. Click on these two internet addresses for further advice and information:
Digital UK Main Site
TV Retune Site
Digital UK are expecting around 6000 homes to contact their advice phone number during this Rowridge Switchover. By far the majority of those will be having a problem with retuning. Their phone help-line (08456 50 50 50) will be extensively manned on each switchover day.
For Wimborne U3A Members, I shall also be manning my own phone/e-mail help-line on 7 and 21 March and again on 18 April, for any member who is having a problem. The Digital Outreach grant will also fund home visits free of charge for anyone whose problem cannot be solved by phone/e-mail, on the day after each switchover date.
Unfortunately It is not possible to provide a universal set of instructions for the process of retuning which will work every time in every piece of Freeview equipment. This is because each manufacturer has produced their own individual way of setting up how it should be done, even using their own unique vocabulary for each aspect. What is possible, however, is to provide a universal strategy for tackling the process and I list that strategy below.
Strategy for the Retuning Process applied to Freeview equipment
1. Follow the instructions for retuning provided in the manual you received with each piece of equipment. If you don't have a manual, they can be downloaded from the internet at no cost. Just Google the Manufacturer's Name and Model Number followed by the word manual, eg "Panasonic TX-L32E30B manual". The equipment does not have to be currently on sale - it is still possible to download manuals for older equipment.
2. Have open at the same time pages 14 and 15 of the Digital UK booklet "Your Guide to Switchover", delivered to all homes in the area a few months ago. If you cannot find your copy there may still be some available from Wimborne Library or the Tourist Information Centre. Alternatively you could send to Digital UK for another copy: Phone: 08456 50 50 50
3. Click on these two internet addresses for further advice and information:
Digital UK Main Site
TV Retune Site
Digital UK are expecting around 6000 homes to contact their advice phone number during this Rowridge Switchover. By far the majority of those will be having a problem with retuning. Their phone help-line (08456 50 50 50) will be extensively manned on each switchover day.
For Wimborne U3A Members, I shall also be manning my own phone/e-mail help-line on 7 and 21 March and again on 18 April, for any member who is having a problem. The Digital Outreach grant will also fund home visits free of charge for anyone whose problem cannot be solved by phone/e-mail, on the day after each switchover date.
Sunday, 4 March 2012
FAQ - 2
Q. I live where I cannot receive Rowridge so have one aerial receiving analogue tv from Winterborne Stickland (which gives me South news) and another aerial receiving digital tv from Mendip (giving West news). What will I receive after the Switchover?
A. I'll answer this for each stage of the Switchover and the Retuning Event on 18 April.
7 March - DSO - 1
Winterborne Stickland will start transmitting all BBC stations digitally on channel 46. The same stations are transmitted from Mendip on channel 61 (at present - due to change in 2013). When you retune, your Freeview tuner(s) will start their scanning process from Channel 21 and work upwards. They will get to the Winterborne Stickland channel 46 first and so will slot all the BBC stations into their correct numbers. Therefore, whenever you then press "1" on your remote you will view BBC-1 South, for example. When the scanning gets to the Mendip channel 61 the same BBC channels will be slotted into numbers 800 and above. All other stations will be received as now.
21 March - DSO - 2
A similar situation will apply to the other two PSB Muxes which start digital transmission from Winterborne Stickland on this date. If you have a Freeview HD tuner it will put the HD stations from Winterborne Stickland (channel 40) into the correct numbers while the same stations from Mendip (channel 58) will be put into numbers greater than 800. Likewise, the D3&4 Mux (ITV-1, C4, C5 etc) from Winterborne Stickland (channel 43) will be stored in the correct numbers while those from Mendip (channel 54) will go into the 800s. All other stations will be received as now, but don't forget to retune on 28 March to continue to receive ArqA from Mendip.
18 April - Retune event
This event applies only to the Rowridge transmitter. The three COM Muxes (SDN, ArqA, ArqB) you will continue to receive from Mendip and their power will have increased on 27 and 28 March. Winterborne Stickland will not be transmitting those three Muxes.
All the above assumes you can receive the new digital transmissions from Winterborne Stickland. The digital transmission power will be 20% of the previous analogue power (200 W instead of 1000W) and Wimborne/Corfe Mullen are not in the service area of the transmitter. It is mere luck of geography which allows such reception now in out of service area locations. Having said that, digital transmissions do not need as much power as analogue transmissions.
There is another possible scenario, depending upon how difficult it is where your house is situated to receive the new Rowridge higher power transmissions. It's not beyond the bounds of possibility that your Winterborne Stickland aerial may receive the Rowridge transmissions at sufficient strength. In which case, because Rowridge will be transmitting the BBC A Mux on channel 24, on 7 March your tuner(s) will lock onto that first while scanning. You can spot this usually by watching your on-screen display while the scanning is happening. Some equipment displays the channel numbers it's locking on to - other equipment doesn't but just provides a progress bar. If that progress bar slows down and holds very early in the scanning it suggests channel 24 is being stored. If you monitor the stability of those stations and all remains well, a change of aerial to receive just from Rowridge becomes a possibility once the DSO and Retune Event are over. A vertically polarised Group A aerial would seem the best bet, but your aerial installer would advise on the actual aerial needed after testing the signal strength: do wait until after 18 April for such a venture.
One final point. To work from two aerials requires the cable from each be joined at some point so only one cable is connected permanently to your tv or set top box (stb). That joining is via a device called a diplexer. A diplexer will lower the signal strength at your tv/stb. A single aerial receiving from just one transmitter will therefore always provide a higher signal to your receiver than that from a two-aerial diplexed arrangement. The difference is not large but could be significant.
A. I'll answer this for each stage of the Switchover and the Retuning Event on 18 April.
7 March - DSO - 1
Winterborne Stickland will start transmitting all BBC stations digitally on channel 46. The same stations are transmitted from Mendip on channel 61 (at present - due to change in 2013). When you retune, your Freeview tuner(s) will start their scanning process from Channel 21 and work upwards. They will get to the Winterborne Stickland channel 46 first and so will slot all the BBC stations into their correct numbers. Therefore, whenever you then press "1" on your remote you will view BBC-1 South, for example. When the scanning gets to the Mendip channel 61 the same BBC channels will be slotted into numbers 800 and above. All other stations will be received as now.
21 March - DSO - 2
A similar situation will apply to the other two PSB Muxes which start digital transmission from Winterborne Stickland on this date. If you have a Freeview HD tuner it will put the HD stations from Winterborne Stickland (channel 40) into the correct numbers while the same stations from Mendip (channel 58) will be put into numbers greater than 800. Likewise, the D3&4 Mux (ITV-1, C4, C5 etc) from Winterborne Stickland (channel 43) will be stored in the correct numbers while those from Mendip (channel 54) will go into the 800s. All other stations will be received as now, but don't forget to retune on 28 March to continue to receive ArqA from Mendip.
18 April - Retune event
This event applies only to the Rowridge transmitter. The three COM Muxes (SDN, ArqA, ArqB) you will continue to receive from Mendip and their power will have increased on 27 and 28 March. Winterborne Stickland will not be transmitting those three Muxes.
All the above assumes you can receive the new digital transmissions from Winterborne Stickland. The digital transmission power will be 20% of the previous analogue power (200 W instead of 1000W) and Wimborne/Corfe Mullen are not in the service area of the transmitter. It is mere luck of geography which allows such reception now in out of service area locations. Having said that, digital transmissions do not need as much power as analogue transmissions.
There is another possible scenario, depending upon how difficult it is where your house is situated to receive the new Rowridge higher power transmissions. It's not beyond the bounds of possibility that your Winterborne Stickland aerial may receive the Rowridge transmissions at sufficient strength. In which case, because Rowridge will be transmitting the BBC A Mux on channel 24, on 7 March your tuner(s) will lock onto that first while scanning. You can spot this usually by watching your on-screen display while the scanning is happening. Some equipment displays the channel numbers it's locking on to - other equipment doesn't but just provides a progress bar. If that progress bar slows down and holds very early in the scanning it suggests channel 24 is being stored. If you monitor the stability of those stations and all remains well, a change of aerial to receive just from Rowridge becomes a possibility once the DSO and Retune Event are over. A vertically polarised Group A aerial would seem the best bet, but your aerial installer would advise on the actual aerial needed after testing the signal strength: do wait until after 18 April for such a venture.
One final point. To work from two aerials requires the cable from each be joined at some point so only one cable is connected permanently to your tv or set top box (stb). That joining is via a device called a diplexer. A diplexer will lower the signal strength at your tv/stb. A single aerial receiving from just one transmitter will therefore always provide a higher signal to your receiver than that from a two-aerial diplexed arrangement. The difference is not large but could be significant.
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