All posts by KMJ, Derby
Below are all of KMJ, Derby's postings, with the most recent are at the bottom of the page.
Deb: The most likely scenario for interference from 4G is where the Freeview signal is weak and the 4G signal is strong. Adding a wideband amplifier to the viewer's aerial with no filtering will result in the 4G signal becoming so strong that it overloads the tuner. The use of group A, B or K aerials where frequency allocation permits, plus good quality double screened coax will minimise unnecessary pick-up of the 4G signal in addition to the use of filters. A very small percentage of viewers who wish to receive C60 or C59 could have problems filtering out a strong 4G signal on say C61, especially if they are receiving from a vertically polarised relay transmitter.It has been acknowledged that changing to a transmitter in a different direction/ on a lower frequency/ horizontally polarised if possible could offer a solution in such cases, otherwise satellite or cable reception might be the only suitable alternative.
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Lesley: Why did the aerial man stop the signal from Yorkshire? Skipton is predicted to offer the best reception overall at your location, subject to there being no local obstructions to block reception. As this is only a PSB only relay, use of a Skipton aerial for BBC, ITV1/2 etc combined with Pendle Forest for the COM muxes would give the best chance of receiving all channels with reliable reception for the main channels. Note that when using two aerials an auto scan would normally tune Pendle Forest into "normal" channel positions, with Skipton in the 800s, unless manual tuning of the desired frequencies is possible.
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anna sharpe: It is possible that your receiver has tuned in to frequencies for a different transmitter to the one that your aerial is pointing to, resulting in it trying to receive a signal that is just below the threshold necessary to display the channels. If the aerial is pointing to Winter Hill check that BBC1 is being received on C62 and ITV1 on C59. It might be necessary to manually insert the Winter Hill frequencies after doing the reset procedure, alternatively start the scan with the aerial unplugged, so as to miss out the lower frequencies as used by Haslingden and Manchester Hulme, then plug it back in at about C48 so that the Winter Hill channels are scanned.
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Carmen Vassallo: The transmitter identification now refers to a region or area rather than an individual transmitter. This is because relay stations show the same information as the parent transmitter, which could be confusing to those unaware that they were not receiving the main station directly. It also helps with selecting the choice of region on those receivers that offer a choice, the receiver then selects (with luck) the strongest signal/best quality from those available for the chosen region. Sutton Coldfield is therefore a West Midlands option. If the channels were lost as a result of doing a retune it could be that old data was retained, in which case doing a factory reset prior to retuning should restore the full list. Otherwise the problem could be too strong a signal on affected mux(es) or single frequency interference blocking reception on affected frequencies.
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conor: That simply won't happen. They might appear on the Freeview "low budget" service in due course to encourage the purchase of Freeview HD receivers, but ultimately I would only expect them to be available on more transmitters as replacements for the standard definition service. Satellite is more complicated, with contracts with Sky and Virgin Media to take into account. Furthermore due to the large number of standard definition satellite receivers currently in use requiring continuation of the SD services it is likely that most commercial HD channels will opt to remain as subscription services on satellite in common with the German commercial networks.
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John: Shopping channels are unlikely to ever transmit in HD due to the extra costs involved. Three SD shopping channels could be a possibility, except for the fact that only a small percentage of viewers currently have DVB-T2 receivers. This factor is also likely to discourage other broadcasters, as it did Channel 5, who ideally would wish to discontinue the SD transmission once a decision to transmit in HD on Freeview is made.
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Lesley: I am assuming that reception from Pendle Forest, which carries 6 muxes is subject to interference or glitches from atmospheric changes at certain times of the day, but Skipton delivers a reliable signal on the 3 PSB muxes (only). This is why I suggested using Skipton for the viewing main channels, albeit with local content from Leeds, and combining this with Pendle Forest to enable reception of the COM channels, plus Manchester based local news output. To combine two aerials on one downlead is not very expensive, requiring the use of a group A + E diplexer. Note that Mux BBCA from Skipton changes frequency to C39+ on 10th April 2013, so the channel split on the diplexer needs to be below C39. Manual tuning of the Skipton frequencies followed by the Pendle Forest frequencies will, on most receivers put Skipton PSBs in the "normal" LCN positions, with Pendle Forest PSBs in the 800s. Auto tuning would put Pendle F. channels in the normal positions with Skipton channels (only BBC1 and ITV on some receivers that don't store the whole mux) in the 800s.
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Viv Gunton: What is the signal strength and quality on the SDN mux (ITV3) compared with that on say BBC1 or ITV1? It is possible that interference which only affects SDN is present, or the aerial position is such that it receives that mux less well than the others. The transmitter power at Hannington was not raised significantly at switchover, it was mainly viewers towards Guildford who would have noticed an improvement following the removal of restrictions in that direction.
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trevorjharris: Ofcom are keen for the Freeview muxes to move over to DVB-T2 transmission as soon as possible, so that more SFN working can be introduced as spectrum is made available for 4G/5G. They are not really bothered whether broadcasters choose to remain in SD or change to HD. Rather like they are not bothered if radio stations choose to transmit in mono on DAB to reduce transmission costs!
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Friday 7 December 2012 7:31PM
Mrs Lynda Ford: The BBC status report shows the Nailsworth transmitter to be off air from 14.26. There is no time shown for a return to service.