All posts by Chris S
Below are all of Chris S's postings, with the most recent are at the bottom of the page.
yes there was a severe high pressure event . For a time I could tune in pictures from transmitters at Sandy Heath , Sudbury , Crystal palace and even Dover! The multiplex on UHF channel 31 is usually the most affected . I believe that interference from the Oxford transmitter is the main culprit because it transmits on most of the same UHF channels as Tacolneston. In North Norfolk we also pick up signals from the continent . Its probable that there will be less problems next year when Tacolneston will change to new frequencies (retune and possibly new aerial then needed) . You will be most affected by interference if you do not have the right aerial . Loft aerials are definitely not recommended in problem reception areas .
If you cannot stand loosing channels a couple of times a year I would recommend switching to Freesat . Freesat uses a dish just like sky and is not affected by high pressure weather. Freesat receivers are not expensive and receive all the same channels as freeview except QUEST and DAVE. FREESAT needs no subscription (unlike sky)----------------------my location Mundesley
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I think the reason people keep wrongly assuming the problem is a fault at the transmitter is that interference in the pre digital analogue TV days often made patterns or snow on the picture . Interference on digital will often knock out a tv picture completely !
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I notice that in the new plan some main transmitters use exactly the same UHF channels as each other . Will there be a frequency offset or other means to reduce the chance of co channel interference?
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Replacing the dipole is not a general solution . It just happened in your case that using an insulated dipole shifted the frequency response to improve the wanted channel. Sheer luck! Usually any modification of an aerial will not improve reception.
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Colchester should see a strong signal from Sudbury with the correct aerial . AS Mike says because its easy for the tuner to pick up the wrong transmitters on similar frequencies (in that area) my guess is that a manual tune is necessary . Use the listed UHF channel numbers listed on the Sudbury freeview page to do this. (note that the "channels" referred to in tuning are UHF channels not the freeview channels)
Some tvs will need the tuning first to be cleared by doing an auto tune with the aerial disconnected.
side note .. the ideal aerial is a type E . I wouldn't yet buy a new aerial because next year Sudbury will get best reception on a type K ! Though in a strong signal area like Colchester if you have a wideband aerial it should work now and next year too after the major frequency change.
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like Brian I have technical qualifications and have worked in aerial design and testing. Yes you can design a good aerial with copper but at UHF its no better than aluminium . I think you are probably making an assumption that because copper is a better conductor than aluminium it should automatically improve any aerial . It doesn't improve a UHF aerial because resistance is low due to the surface area. its mainly the thickness length and position of aerial elements that decides the performance. I'm sure you could improve a cheap aerial on certain channels by carefully optimising the dipole size but the point is its not whether its copper or aluminium that makes the difference.
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Nick unless you've tried a near identical dipole in aluminium you've havn't the full facts . I can see a lot of your posts give good info based on long experience but you have to be careful what you say if you have not got relevant training in the subject. I'll take up no more space on this subject.
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Tricia: re reception in edgefield . I live not far away in North Norfolk . com7 is the most unreliable group here too even though I do have a wideband log aerial . I notice its worse during high pressure weather conditions so I guess that it is interference from the Oxford transmitter that uses the same UHF channel 31.
The problem should go away (touch wood) next year when Tacolston stops using channel 31 . Meanwhile I use freesat because fromn august 1st freesat now transmits all the same channels as freeview including Dave!
Fresat does not suffer from continental interference . Ocassionally a problem here near the North Norfolk coast.
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sounds a bit like the only change might be a new source of interference such as from a telephone mast . Or also possible that you are getting a signal from a Dutch transmitter . There are some on UHF channel 31 . But Dutch interference usually only shows up occasionally in times of high pressure weather. Loss of signal shows as a low reading of signal strength . Interference can read like high signal strength fooling you into thinking everything is ok. Also living near the coast I have reverted to Freesat to avoid continental interference . I may switch back to freeview next june when the freeview channels will be changed but there is not much incentive as you can now watch all the same channels on freesat.
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Wednesday 18 January 2017 11:06AM
People should not retune during a period of poor reception they may well tune into say Sudbury instead of Tacolneston . Then when reception actually goes back to normal they will loose some channels because they wont still be tuned to Tacolneston!