All posts by KMJ, Derby
Below are all of KMJ, Derby's postings, with the most recent are at the bottom of the page.
Hertfordshaz: Have a look in the 800s of the channel list for any alternative channels which carry Anglia news. When scanning if the London signal is found first (or Anglia is off the air or blocked by interference) you will find London channels stored on the "normal" channel positions. Retuning might restore the Anglia channels to their former location, but really you need to clear the channel list and do a manual tune, if possible, on the Sandy Heath frequencies.
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The best advice is surely to do a retune if and when you wish to make a change to the services being received. Personally, I retune when there IS tropospheric ducting, in order to find out what is available, but as Dave Lindsay says, this would clearly be inadvisable for anyone trying to find lost channels. Retuning is also unnecessary for an old lady (for example) who sticks to news and soaps for her daily viewing and would not watch any extra channels even if she had them. Likewise, viewers who live in overlap areas with resulting difficulty in getting the correct frequencies tuned in might prefer to leave well alone.
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Nick: Do you have Dave or Sky News? If not, it would appear that you are missing Mux ArqA. Try a manual tune on C60 in order to see what signal strength and quality is present.
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Stu Seddon: You should be able to receive the full set of Freeview channels. If you have ITV1 and C4 you should also have Channel Five as this is on the same mux, available from all UK TV transmitter sites after DSO, Additionally, if you can receive QVC you should have the remaining Channel Five group channels. Try a manual tune on C27 for D3+4, and C25 for SDN from Rowridge. If you have a non functioning Channel Five in the channel list, do a factory reset to clear the old data before retuning.
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paul: If retuning restores channels which are broken up or missing, it suggests that possibly you are receiving signals from more than one transmitter. Does your receiver do an automatic retune each night? If so this facility should be turned off if possible, after tuning into the correct set of frequencies for the Sudbury transmitter. You do not say which muxes are giving problems. The PSB muxes are possibly being received additionally from Bramford which is in the same direction as Sudbury, but transmit with vertical polarisation. If it is the COM muxes that are giving problems, these are also predicted to be receivable from Tacolneston at your location. When doing a scan for channels try to note which frequencies are being stored when you have correct working channels, then if possible check which frequencies are being received when the channels are breaking up. I should also mention that in the (less likely) event that Bramford or Tacolneston signals give good reception whilst Sudbury gives breaking up reception this would indicate Sudbury to be delivering too much signal.
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Snarf: What do you now have stored in position fifteen of the channel list? I would suspect that the inversion effect could have been at work delivering out of area signals, unless an automatic retune took place which coincided with Rowridge being off the air, resulting in an alternative frequency being stored for ArqB.
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T J Bull: Are the channels on Mux D3+4 being received from the transmitter to which the aerial is pointing? Crystal Palace and Sudbury are both shown as possibilities for reception at your location. Check if there are any alternative channels stored in the 800s of the channel list that work correctly. You could also try moving the position of the connecting leads relative to the TV and recorder to make sure there is no interaction between them, causing interference to block the required mux.
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Dave Lindsay: We are now in a situation where technology is changing so fast that there does not seem to be any answer to the problem of constantly having to buy new equipment. Some people moan about needing a new Freeview box or a new aerial every few years, but happily accept a situation where a new mobile phone is needed every couple of years or a computer costing hundreds of pounds is required to use BBC i-player because the BBC have decided to make it no longer compatible with IE6 or older windows systems. I sometimes wonder if the planners were already aware of plans to use more spectrum for 4G, but delayed the transfer of transmission of the COM muxes in group A because DVB-T2 would need to be employed and too few people have the necessary receivers at present.
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Len Dixon: The planners are so keen to utilise every possible bit of spectrum that it is inevitable that frequencies are used close to those of broadcast transmitters. It is somewhat alarming that there is talk of trying to use frequencies in between those of the TV and radio transmitters in areas where there is any space. What will the band II (FM) frequencies be used for after transfer of national and regional radio to DAB? It is fair to say that Freeview is a more user friendly system and is very cost effective in built-up areas. In fact satellite transmission would need terrestrial back up in urban areas to achieve the same penetration as the current Freeview network. I think it was more of a political rather than practical decision to convert every relay to digital rather than utilise satellite in the more remote areas. The question of 4G interference is really one of viewers needing aerial systems that incorporate good quality screened cable (including fly leads), and as a first line of defence using a group A or K aerial in those areas where this is appropriate to give best possible gain on the required frequencies. Manufacturers of masthead amplifiers could produce a range that incorporate a suitable filter, removing the need for additional equipment to be fitted to viewers installations.
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Wednesday 27 June 2012 10:41PM
tony: It is possible that some parts in the South of England are currently experiencing the inversion effect at work, resulting in normal reception being blocked by out of area signals. Apart from that, the Digital Uk postcode checker shows that predicted reception for the COM muxes at your location is best from Crystal Palace. In fact you are shown as possibly losing ArqB completely from Bluebell Hill in due course! You could try to do a manual tune on C45 to see if there is a usable signal for SDN (QVC etc) from Bluebell Hill, after first clearing the channel list of any existing data for the SDN channels.