All posts by Michael Perry
Below are all of Michael Perry's postings, with the most recent are at the bottom of the page.Whenever i watch moving sport especially football I experience
Tuesday 11 October 2016 10:56AM
Bungay
Tuesday 11 October 2016 10:56AM
Bungay
derek gill:
1080p is a system of progressive scanning in the vertical direction. It means that each adjacent horizontal line making up the picture is sent immediately after the previous one directly above it.
1080i means the picture is interlaced, that is where each alternate line is transmitted until the screen area has been covered by half the number of lines need. Then the other lines in between those already sent are transmitted to fill in the spaces.
Interlaced display was how the 'old' 405 and 625 line analogue transmissions were sent out. Currently, digitally encoded transmissions such as Freeview are sent out as progressive scan. The advantage of progressive is that there is little, if any, flicker and the screen refresh rates can be faster. It is generally considered that progressive gives a better viewing experience.
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Bob Ratcliffe:
Yes. The same satellites used by Sky are used for Freesat so the same dish is perfect for getting Freesat - even the LNB and wiring is the same. Just connect the cables from the dish LNB to the inputs of your Freesat receiver. Good ones are available for reasonable prices and you can get a STB that can record as well for around 150 or so for a good one. There are some cheaper but they are often suspect for reliability in my experience.
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Nicolas:
It is not 'ghosting' as that only affects analogue transmissions. What people are seeing is the effect of a low bit rate transmission, as MikeB suggests. If the bit rate is low then what they transmit is only a full rendition every several fields followed only by difference information. The effect is for there to be a 'stuttering' of the moving image as it traverses across the screen, particularly noticeable on fast moving elements, such as Formula 1 cars, football and rugby players, horses, etc.
It is not a fault but a well known, to electronics engineers at least, artefact resulting from the bit rate being transmitted having been set too low for the programme. The reason they do that is so that more channels can be incorporated within the available data set for a particular multiplex (that can only carry a finite amount of data).
The DVB-T2 transmissions used mainly for HD services is better at displaying moving pictures with less noticeable artefacts such as these. In the future, all Freeview transmissions are likely to use DVB-T2 encoding, which means less of these picture disturbances but viewers will all need equipment capable of receiving HD services, so a full HD set is required and not just an 'HD ready' set that does not have the DVB-T2 capability.
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Colin Smith:
Looking at the information accessed via the blue boxes below your posting, it is clear that Bluebell Hill is the best option. Your are only 16 km away and your aerial would need to point due west. However, when you retuned after moving it is likely that your equipment picked up Crystal Palace instead of Bluebell Hill, they are almost in the same direction. Crystal Palace signals are in Group A so appear before those from Bluebell Hill which are in Group B. The digitaluk trade information shows which channels you should be using. I suggest you firstly check that your aerial is a Group B type, or better still a log-periodic one, and is aimed due west at 270 degrees. Then unplug the aerial from the equipment and do a full retune to clear out the unwanted settings. Then start another retune but plug the aerial back in when it reaches Channel 31. That should mean it get the services from Bluebell Hill. If there are any problems, then a manual tune of each multiplex may be required, using the channel data shown in that digitaluk trade information.
BTW, there is no TV transmitter in Maidstone shown on any of the location data available.
The only other transmitter possible is at Dover, which is south east of your location but is shown as giving very poor reception. It is a Group C service so an aerial for that will not be very good for Crystal Palace and not ideal for Bluebell Hill.
Hope that helps?
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Colin Smith:
Sorry, also meant to mention that as you are relatively close to Bluebell Hill you should ensure that the signal strengths shown for each multiplex is not too strong. A strength between 65% and 85% is best, more than that usually results in pictures breaking up and often sound problems. You will not need any form of booster or amplification.
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nicholas:
In the UK UHF television was only broadcast on channels 21 - 69, frequencies higher than that were allocated to other non-TV broadcasting. The allocation of channels was by an international agreement way back in the fifties and sixties. Since Ofcom was given the UK responsibility to oversee frequency usage in the UK, there have been a few changes with more to come in the next few years.
As far as I am aware, VHF is not capable of carrying sufficient bandwidth of data for 625 line PAL transmissions with a higher image definition than was possible with 405 line services, hence UHF was used. Agreed it has a shorter range so for fuller coverage more main and repeater transmitters were needed - but that allowed regionalisation to smaller areas. That is now considered a commercial advantage.
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Nicolas:
To my certain knowledge, many of the TV transmitters are still fed via microwave links and not satellite links (I have yet to see a microwave dish on a TV transmitter site point up at a satellite! And I've been in the industry since 1960.).
The carrier frequency can be significant in planning services. Band 1 Channel 1 has a video carrier allocation at 45 MHz, for it to carry a DVB-T2 multiplex, for example, would mean going way outside the channel bandwidth allocated by international agreement.
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Alistair Broadley:
Following on from that said by jb38, the only other alternative, if the aerial cannot be repositioned, is to consider Freesat - providing the new hotel structure does not obstruct the view of the satellites. As a very rough guide, check to see if the hotel is anywhere near a line of 28 degrees east. If it is then there may even be problems getting Freesat and Sky. If it is not then it may be worth one resident trying to get Freesat. Sky would be an expensive alternative as it is a subscription service.
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Antoinette Sorreda:
Your first action should be to switch off the Sky box with the remote control and then unplug the mains supply to the box by switching off the mains socket and pulling out the black mains plug from the back of the Sky box. Then wait at least 5 minutes. Then put the mains plug back into the back of the Sky box followed by reconnecting the mains supply and switching that on. Then wait another 5 minutes to let the Sky box set itself up again. Then use the remote control to switch it back on to its normal operation and check that the TV shows a picture and gives sound (it will normally show channel 998 first). If all is well then problem solved. If you still don't get sound and pictures, try changing channel to 101 and you should get BBC1. If not, then the Sky box probably has a fault that should be reported. If you took out the insurance it should be covered, otherwise they will charge.
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Tuesday 11 October 2016 10:47AM
Bungay
Julie Rowe:
You are only 7km from the Rosehearty transmitter which is at a bearing of 55 degrees from your location.
It is highly unlikely that you will need an amplified aerial system as you are so close to the transmitter.
If you click on the small blue box labelled 'digitaluk trade' at the bottom of your post it will tell you more details.
Note also that there has been some engineering work going on at the transmitter.