All posts by KMJ, Derby
Below are all of KMJ, Derby's postings, with the most recent are at the bottom of the page.
Nick: If the plan to extend the number of frequencies allocated to 4G takes place, C60 possibly down to C49 will be lost to broadcasting. There are a number of possibilities suggested for the COM muxes but it is most likely that they would be allocated frequencies in group A. This would of course require agreement with the other countries likely to be affected by such use, so I would guess that if there is any deviation from the plan due to avoiding interference to or from continental transmissions it would be more likely to occur in the East or South coast areas. The time scale is a bit vague, as both plans really require DVB-T2 transmission to be used to allow SFN working, so would not cater for the majority of receivers in current use. 2015 and 2020 are two dates which have been associated with the suggestions but the COM muxes are licensed beyond that time.
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Suzy: The transmitter identification names were changed to "area" names some time ago so as not to give incorrect information on the signals from relay transmitters. Sandy Heath and dependant relays now show Cambs and Beds, Oxford is Oxon and Bucks and Belmont is East Yorks & Lincs. If your aerial is pointing NNE/NE to Sandy Heath you should receive BBC1 East and ITV1 Anglia at positions 1 and 3 of the channel list. If the aerial is pointing WSW to Oxford then BBC Oxford and Meridian ITV1 should have been stored. After you have established which transmitter you should be receiving, do a manual tune for the correct set of frequencies after first clearing the channel list. SH is C24, C27, C48, C51, C52 plus C21 (HD). Oxford is C53, C60, C55, C59, C62 plus C57 (HD). Note that if you are seeing a signal from Belmont (which the "variable" prediction for C53 and C60 from Oxford suggests is possible when conditions are such, the channels will probably give unreliable reception if stored.
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jb38: Sorry, I didn't realise you had already replied until after I had sent my post.
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Julie ayling: Have you tried the set top box downstairs to see if it will receive the BBC channels on an aerial connection that you know to be working? If it works, you know that there is a problem with the signal being supplied upstairs and you will need to reposition or improve the aerial. If it still refuses to receive the BBC mux there could be a problem with the sensitivity or characteristics of the box, in this event if you give details of the make/model of the box a check can be made as to whether it is one known to have issues. Likewise, if you give some indication of your location, preferably a postcode, a check can be made on predicted reception in the locality.
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Richard: Is this Freeview or are you receiving satellite channels? If you have "no signal" on the HD version on satellite, try the SD channels which should be working fine.
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Jim: I have just had a look at the William Hepburn's tropospheric ducting forecast for last Friday and there was (for about 6am)a fair chance of ducting in the SE of England, stretching into East Anglia and the North of France. Although the digital signal on C50 is four times that which would normally be used to match the former analogue coverage, the analogue service did not have to contend with C50 being in use at Tacolneston, the nearest English high power transmitter at that time would have been Sutton Coldfield.
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Kevin Fagan: Further to what Mark Fletcher said above about single frequency interference, it is possible that ArqA from Black Hill is strong enough at your location to interfere with PSB3 from Tay Bridge. If this is the case, a different aerial position could offer a solution to the problem. This could mean as little as a few inches lower/ higher or to either side. Alternatively, if you have a reasonable line of sight to Angus to the North of your location, you might be able to receive a full Freeview service from there.
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Shai: If your aerial was suitable for the frequencies in use before switchover, in your area it will also be suitable after switchover as the frequencies are still within the original aerial grouping. Did you do a factory reset to clear the channel list of old data before you scanned for the post switchover services? Also, if you have a booster on your aerial it is possible that the signal is now too strong. In this event you will need to connect the aerial direct to the tv without the booster, or insert an attenuator in the aerial feed to reduce the level of signal.
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Jonathan Currah: It appears that you lost reception of SDN and ArqB muxes. Check that your receiver is tuned to the correct transmitter for the direction in which your aerial points. For Bluebell Hill this is C45 for ITV3 and C54 for Yesterday/Film4. You are predicted to have good reception possible from several transmitters, so incorrect frequency selection during a channel scan is possible. There is also the possibility that tropospheric ducting caused out of area signals to block reception of the missing channels, this being possible whichever transmitter is tuned in, but even more likely if, by chance, these two muxes were tuned to the "wrong" transmitter.
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Wednesday 25 July 2012 9:29PM
Paddy Webber: There is a large overlap of the coverage areas of the Crystal Palace and Sandy Heath transmitters. When scanning for channels, the CP signal on C23 is found before SH on C27, so BBC London channels are placed in the usual positions in the channel list, then when the SH signal is scanned, upon detecting a regional variation, many tuners will put either BBC1 East, (or sometimes all the channels on PSB1 from SH) into vacant positions in the channel list, usually in the 800s. Some receivers offer an option to select a regional preference for the allocation of channels into the LCN positions, but on receivers not having this facility it will be necessary to clear the channel list, then do a manual tune of each of the Sandy Heath frequencies to store the correct set of channels.