All posts by KMJ, Derby
Below are all of KMJ, Derby's postings, with the most recent are at the bottom of the page.
Keith Davies: After checking the William Hepburn's tropospheric ducting forecast for Northern Europe it would appear that your reception could be affected by out of area signals travelling further than normal, resulting in interference to your normal services. Rumster Forest and Rosemarkie both use frequencies received from Craigkelly and reception of transmissions from Norway is another possibility. In the event that alternative signals were present when you retuned you could have replaced your normal channels with a selection that don't work. (All DTT from Norway is MPEG4, so would need a Freeview HD tuner to decode it if it was receivable at your location) When conditions return to normal you would then need to carry out another retune to restore the correct channel list.
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Nick: a look at the Digital UK reception predictions for your location show that whichever transmitter is chosen there is unlikely to be reliable reception on Freeview across all services. It is fair to say that the more platforms you are able to use the more likely it becomes that you will be able to make the best use of your TV. If you are able to receive satellite transmissions they are likely to offer the most reliable TV service at your location, with Freeview for back up on those occasions that inclement weather or sunspots scupper satellite reception. Use of the internet too is another option, although reliability of online delivery can be very frustrating at times. Regarding Freeview I would be inclined to have a second aerial pointing to Sudbury/Rouncefall for backup on the PSB muxes as the prediction suggests that to be more reliable than the other options.
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Neil P: if you are still receiving the services on a TV upstairs it suggests that the HD receiver is either tuned to a different transmitter for reception of ITV and ITV+ or, if a different aerial is in use, the aerial on the upstairs TV is positioned more favourably for reception of the PSB2 multiplex. Is the HD receiver also failing to receive Channel 4, C5, ITV2 etc? If these services are still present and correct check the 800s of the channel list for working variants of ITV and ITV+ as there are occasions when after viewers have selected a particular choice of region in the tuning menu, the tuner stores services for that region in LCN positions in the channel list when it identifies a regional variation but stores national services on a 'first example found in the scan' or 'strongest signal available' basis.
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John Jenkinson: The COM4, COM5 and COM6 muxes from Durris share frequencies with the PSB muxes from Knock More. This results in low level signals from Knock More causing reductions in signal quality or blocking of reception for viewers of the Durris COMs in affected location a. Sometimes careful positioning of the aerial intended to receive signals from Durris can help in screening out the unwanted interference from Knock More. Any problems affecting BBC programmes are not caused by Knock More, but could be helped by careful aerial positioning. Aim for signal strength less than 90 percent but quality as high as possible, preferably 100 percent.
Also beware of interference from HDMI cables (if fitted) causing problems to individual frequencies.
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Peter: yes, for the past few days the weather conditions have been such that in some areas signals that normally give good reception have been subject to interference from distant transmitters resulting in glitching and the dreaded 'no signal' being displayed for various periods of time, whilst some services were received loud and clear tens or hundreds of miles outside their normal range. If you retuned because the normal programmes were not being received it is likely that services you have been watching for the past week were from different transmitters to the one that your aerial is pointing to. Once conditions changed or returned to normal the strength of the alternative signals would diminish or the signals disappear altogether, making another retune necessary to restore the correct channel list.
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Richard Horton: if another signal is blocking reception of the PSB1 mux from Tunbridge Wells no amount of retuning will restore reception until the unwanted interference has been removed or diminishes to a level that it no longer corrupts the data on the required mux. As this happens regularly and only to PSB1 it leads me to wonder if a signal that normally stops short of your location or is always present, but at an extremely low level, rears its head whenever conditions give a slight boost to its range. The COM5 mux from Sandy Heath would appear to be a possible culprit after studying coverage maps. If this is the case it might be possible to improve matters by slight repositioning of the aerial so it sees less of the unwanted signal. It is worth mentioning that the RF modulator in a Sky box or VCR being set around the frequency being blocked or interference from poor HDMI cables is sometimes found to be the cause of a mux being lost for a period of time with reception being restored whenever equipment is switched off or moved.
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Tracy Jackson-Brown: Is there no BBC1HD and BBC2HD at positions 101 and 102 in the channel list?
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All viewers: If any BBC channels were lost on 1st June 2016 to viewers using The Wrekin, Bromsgrove or Lark Stoke transmitters it will be necessary to carry out a retune to restore the service if these channels are still missing. This is because the PSB1 multiplex was reconfigured at that time to facilitate carriage of BBC Radio Shropshire.
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phill gethins: the PSB1 multiplex at The Wrekin, Bromsgrove and Larkstoke transmitters has been reconfigured to facilitate the transmission of BBC Radio Shropshire on Freeview. Whilst many tuners will automatically update to accommodate the changes some need to have a retune performed to achieve this. It might be necessary with some models to perform a factory reset (or return to shipping conditions) to remove all trace of the old PSB1 data before carrying out a retune to avoid the new data being overlooked. If PSB1 is still missing afterwards I can only suggest performing a manual tune on C26 to restore it in the tuner's memory.
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Sunday 22 May 2016 10:45PM
Chris: the latest tech parameters spreadsheet from Ofcom shows that Norwich 10B is now transmitted from Mendlesham.