All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
Jeanette Phillips :
In addition to the full postcode, please tell us which way (approximate compass bearing) that your aerial is pointing, and whether it's external or in the loft.
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craig:
You are correct in that retuning shouldn't make any difference ....... unless ......... you weren't correctly tuned before doing so or you've now tuned to unusually strong signals.
IF you are correct;y tuned, it's never advised to retune if you have no signal or badly pixellated pictures, as this often just clears the correct tuning.
Check in your TV tuning section which UHF channels you are tuned to for each of the multiplexes.
Now being correctly tuned depends on which transmitter your aerial is pointing at. Even so, aerials have what are called "side-lobes" and can pick up signals from other directions/hence transmitters in some conditions (typically the sort of conditions we have at present!). You might readily get signals from 3 other transmitters.
Which way (rough compass bearing} is your aerial pointing and are the rods (or squashed Xs) vertical or horizontal?
If it's pointing at Bretch Hill it should be pointing at compass bearing 243 degrees - that's roughly WSW with its rods vertical.
It may be pointing at the Oxford transmitter compass bearing 159 degrees ~SSE with the rods horizontal.
Do you normally get TV Channels like Sky Arts (LCN11), Quest (LCN12) & Drama (LCN20)?
Those will not come from the Betch Hill transmitter.
Also, reception in many areas is being disrupted by current weather conditions -
They have been causing Tropospheric Ducting affecting much of the south coast and southern parts of the country on Saturday and extending into the Midlands and North of the country through Sunday including East Anglia, now currently affecting Wales and England. These conditions have been unusually quite extreme on occasion recently.
This causes interfering signals from distant transmitters in Europe or the UK to affect reception of your wanted signals. This can periodically last, seconds, minutes and sometimes much longer - Do NOT Retune.
There is nothing you can do about this apart from wait for conditions to change, or use online streaming if available.
IF you did retune, you'd be best manually retuning the UHF channels for your transmitter, as detailed in the top section of the relevant transmitter page.
The BBC and Freeview have issued warnings -
High pressure weather conditions impacting TV & Radio services - from 07 October | Help receiving TV and radio
High pressure could affect reception across parts of the UK this week | Freeview
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Ian:
There is plenty of information in various places. For a start try reading my post immediately before yours.
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E McC:
Ha, I was just about to post similar information, then saw Steve's post. However this might be a slightly tricky one for you.
First, to be precise, there is no such thing as a digital aerial. Aerials are aerials, they pick up RF signals, they don;t care if the "modulation" on the RF is analogue or digital etc.
2nd, what is important is the aerial Group. I hope it's a Group K and not a Group T/Wideband, the latter will leave you vulnerable to possible interference from mobile phone masts that may use/start using the 700MHz band. You are surrounded by mobile phone masts!
You may have already received a postcard from https://restoretv.uk If not, go to the website, scroll to the postcard box, click Not sure and put in your postcode etc.
Should you have any unexplained interference problems (ignoring current weather conditions which should clear up in a couple of days) you can always contact them for a Free Filter.
The other "tricky" point is that for reliable reception from Londonderry, then aerial rods (or squashed Xs) should be vertical, whereas Holywell Hill is horizontally polarised. However because it's quite close and 20kW power, you may still get an adequate signal and luckily both transmitters are in a general westerly direction from you.
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Caspen:
The conditions are continually changing at present and in any event there will be slight differences between day and night.
TVs that automatically retune are a pain in the **** when we have such weather conditions or even when there is Planned Engineering, and often when there is "no signal" from your correct transmitter, they can then get tuned to weak unreliable signals from other transmitters!
Have a look in the TV Tuning section and have a look for an option to turn off/disable the automatic updating/retuning. If you aren't sure, post the make and precise model number and someone should be able to advise.
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Jeanette Phillips :
I had also meant to include the fact that this DID occur before DSO. With analogue you started off with lots of wiggly lines over the picture, maybe some buzzing and hash on the sound, until the channel became unwatchable and inaudible. You may have even seen some foreign pictures.
Before UHF TV channels, back in the old B&W 405 line days, similar problems commonly happened with the BBC channels in Band I, but it was a slightly different atmospheric phenomena called "Sporadic E" (referring the the E layer of the atmosphere). We used to call it "Continental Interference" !
Also the current conditions can/are affecting DAB and FM radio transmissions in different places.
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michael:
Hi michael. This one in theory, if you click on the menu and then select what you want to look at. The problem is some pages haven't been fully updated since B700 there was a lot of work to do and the site owner was struggling as most info on the changes came from pdf docs which are difficult to read and extra info except manually, things are better than they were though, there's also a lot of historic info that is difficult to find elsewhere.
The other "best" one is mb21 mb21 - The Transmission Gallery
It's a brilliant site, normally very accurate, has lots of pictures as well and a fair bit of historic info.
For a comprehensive list in one place, OFCOM's documents BUT they also have some errors, so it pays to cross check with other sources.
https://www.ofcom.org.uk/…xlsx
See the following pages on OFCOM's site for lots of useful info
Spectrum information - Ofcom
For radio, these documents listed here are very useful
Spectrum information - Ofcom /radio-tech-parameters
That should keep you busy for a while :)
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Margaret Bacon:
The important point to note about any disruption to your signals whether it be caused by Engineering, Faults, or Weather conditions, is that if you know you were correctly tuned to start with, then Do NOT Retune. (You can't tune to signals that aren't there or have severe interference.). Often under those conditions it'll clear your correct tuning so you have to repeat try until you get them back, which in a worst case could be some time!!
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michael:
Yeah, sometimes you wonder about some of the designers of modern "tech" whether they have any practical clue about using it!
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Tuesday 10 October 2023 9:32PM
Jeanette Phillips :
It doesn't happen every time we have "lovely weather". Sometimes - more often with high pressure but not always, it can happen in winter as well, we get these Tropospheric conditions. They have been quite extreme on occasion this time. See my post further up the page Caradon Hill (Cornwall, England) Full Freeview transmitter | free and easy for 21 years
Now, your location may not be the best for reliable reception from Caradon Hill. On a random check in your locale, there was better reception from the Redruth transmitter which is also a lot closer. However we'd need a full postcode to check your predicted reception as the local terrain can make a big difference. We could then possibly offer some advise that might help you get more reliable reception.