All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
Richard:
We need a full postcode to look at the predicted reception at your location. I notice that in the past you have also talked about reception from Oxford. What sort of aerial setup have you got?
The tropospheric ducting that we've had in recent days has been unusually strong for the time of year. It is slowly subsiding and you should see an improvement as the night wears on. You may have noticed that the weather has also been unusually warm!
As I'm sure you can appreciate, the broadcast frequencies have to be "shared", not only with transmitters elsewhere in the UK, but Europe & the rest of the globe, as they always have been. If everyone just increased their power, then the mutual interference would be a lot worse at times like this, but also at times of more marginal ducting.
Unless we can suggest some improvements to your reception, it's a case of grin and bear it unfortunately.
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Mrs Diana Amory:
First let me wish you a happy new year and I'm sorry to hear it upset you, I know that others who live alone had similar feelings.
Yes it was adverse conditions called "Tropospheric propagation" or "Ducting" and is something that's more common in the summer, but the recent conditions have been unusually strong for the time of year, even in summer we rarely see it as strong as this.
Let me also say at this point, this is an independent help site, it's not the broadcasters, nor are we responsible for them, but I will say the abysmal lack of information they put out is unacceptable.
I'm afraid there's always a chance this could occur again due to unusual conditions, just like the weather in general has become more unusual at times, but it's not that common.
Do you not have a radio set you could use if this sort of thing happened again?
Whilst there are predictors out there that try to predict these conditions, they aren't 100% accurate, just like weather forecasts which can be inaccurate or suddenly change.
I hope your Freeview reception is normally OK.
Do post back if you have any more concerns or want any more help.
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Nigel Johnson:
MikeP has already commented about tropospheric ducting. The only thing I would add is the tropospheric propagation conditions have been unusually strong for the time of year, even in summer we rarely see it as strong as this. Have you not noticed how the weather has been unusually warm? But also note that high pressure doesn't mean that temperature inversion also occurs.
In general, the only time engineering work gets postponed is where engineers need to climb/work on a mast, generally for antenna work and the weather is too bad to do so. No antenna work is likely to be needed as that was completed some considerable time ago.
There is only one change at Sandy Heath on the 12th Feb. when the SDN/COM4 multiplex moves from UHF C51 to C33, there are no power changes.
If you can do manual retunes/scans then you would probably get away with just doing so for C33 if conditions were such that you might lose other multiplexes.
It's also worth remembering that frequency allocation is subject to International Agreements primarily through the ITU. Then within that there is the European Radio Spectrum Policy and The European Conference of Postal and Telecommunications Administrations (CEPT) which has representatives from member countries. They carry out studies and other activities to harmonise the use of the radio spectrum in Europe, and have supporting bodies such as the ECC & ECO also the Radio Spectrum Committee (RSC). Recommendations/decisions are made and this usually results in EU level legislation. EU Member States who have representatives on the various bodies, manage the radio spectrum in their national responsibilities, in the case of the UK this is OFCOM.
The particular channel allocations, powers and radiation patterns at each transmitter results from studies and agreements with neighbouring countries to ensure little chance of interference with others transmitters using those particular frequencies. (I have so far only come across one case in the UK of what I would regard as a cock-up & that affects only a small area).
The squeezing of Freeview channels closer together, as you put it, is unlikely to have any significant effect. With the sort of propagation usually seen, interference usually comes from greater distances, eg. Yorkshire transmissions being received on the South Coast/Isle of Wight. Channel sharing of transmitters that sort of distance apart has always been the case. In the old B&W 405 line analogue days, on one occasion I recall receiving pictures from Eastern Europe ! and we used to talk about "Continental Interference". So that should give you some idea about the potential effects of such unusual propagation.
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Simon Watkins:
As has been said quite a few times round here (see previous posts) the site owner has not had the time to keep up with all the 700MHz clearance changes. There are 1100+ transmitters in the UK. See my post at the top of this page (p203) for detailed information.
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E J Gooding:
It's the weather. Temperature Inversion to be precise, often comes with high pressure How clear skies and fine weather can affect your TV reception | Help receiving TV and radio & Effect of tropospheric ducting on Freeview | Help receiving TV and radio see also
Holiday black-out: do not adjust your TV - RXTV Log
It did happen with analogue http://tx.mb21.co.uk/feat….jpg ... is an example of what's probably the BEST you'd have got
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Simon Watkins:
I can't see where MikeP's post is to which you refer. Can you mention where it is please?
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Tuesday 31 December 2019 6:19PM
John:
Hi John, if you happen to come reading, a happy new year to you.
Was just checking a few things out and was "prompted" to go and look at the checker for EM and Bils after spotting something on the checker for other transmitters.
Hmm, more on that in a moment.
As you know, I'd previously mentioned that you'd likely lose COM8 from Bils after 13th Nov. and COM7 next year (5th Feb.) after retunes elsewhere. I can't find any mention that I made about you also losing COMs4-6 from Bils after 12th Feb. I don't recall seeing that, the prediction may have changed or I didn't notice! You are still predicted to get PSBs1-3 from Bils with no issue.
You are still predicted to get PSBs1-3 & COMs4-6 from EM with no problem, COM8 as it is now, and COM7 OK but maybe less after 5th Feb. and 4th Mar. about the same as COM8.
But now, here is the total speculation - I'd noticed on many (all that I've looked at) coverage checker pages, where it had previously said "Final prediction 2020" it now says "Final Prediction 2025" - that's changed in the last few days! It also applies to all that I've checked with COMs 7&8 - so are we to speculate that COMs 7&8 will continue until at least 2025?
One thing we do know is that the current licence for COMs 7&8 runs until 2026 with a caveat that 2yrs notice will be given if it is to be terminated sooner. So at least they should remain until 2022 as I've not seen (can't find) any announcements from OFCOM or Arqiva to the contrary or notice being given.
For anyone reading by the way, the predictions I was talking about at the start of the post are for John's location, not everyone, so others won't be necessarily losing any reception from Bilsdale.