All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
Howard Keene:
Predicted reception can vary considerably across your postcode, most likely due to the geography at some point between your location and the transmitter. Lower numbers in the postcode are predicted good reception, mid range number vary from "variable" to poor, and high numbers good reception of the PSBs but variable reception of the COM multiplexes. BUT also, several transmitters are receivable across the postcode. With the weather conditions around the time of the retune, signals from more distant transmitters could cause interference to wanted signals.
That all said are you sure your aerial is pointing at the Nottingham transmitter? Although it's the closest, it doesn't always give the best signal. You may be getting reception from Waltham (even then it may be slightly variable for the COM multiplexes). Neither transmitter is currently listed for Planned Engineering and I can't find any fault reports for either.
If your aerial is pointing at Nottingham, it should be pointing at a compass bearing of about 259 degrees that's 11 degrees south of due West and the aerial rods (or squashed Xs) would be vertical.
If your aerial is pointing at Waltham, it should be pointing at a compass bearing of about 136 degrees that's almost exactly SE, and the aerial rods (or squashed Xs) would be horizontal.
Having established which transmitter you should be tuned to, you can then check in your TV's tuning section if you are tuned to the correct UHF channels. Remember, reception will depend on precise location.
In the order PSBs1/BBCA, PSB2/D3&4, PSB3/BBCB HD, COM4/SDN, COM5/ArqA, COM6/ArqB, Local -
For Nottingham the UHF channels are C27, C24, C21; C33, C36, C48; C44.
Reception of the Local multiplex could be good or very poor.
In the order PSBs1/BBCA, PSB2/D3&4, PSB3/BBCB HD, COM4/SDN, COM5/ArqA, COM6/ArqB, COM7, Local -
For Waltham the UHF channels are C32, C34, C35, C29, C37, C31, C55, C41.
Reception of the Local multiplex could be (very) poor, and COM7 variable.
If you are incorrectly tuned, try a manual retune, for Nottingham, UHF C36, for Waltham C37. If that doesn't correct things, try unplugging the aerial and doing a full automatic retune which should clear all existing tuning as nothing should be found, then plug the aerial back in and repeat a retune, ideally a manual one for each relevant UHF channel.
If you are still having problems, have you altered anything in your installation recently? Check if other flats are having the same problem. Post back with any details.
| link to this comment |
Anthony:
The figures you have given suggest that not only have you got adequate signal strength but possibly too much!
What are the precise figures for strength and quality for each multiplex on your LG TV?
You are predicted to get very good/excellent reception from Winter Hill.
You should not be tuned to UHF C39, that is the D3&4/PSB2 mux from the Woodnook vertically polarised relay 1km from you (compass bearing 184 degrees, almost due S).
Your aerial (horizontal) should be pointing at compass bearing 215 degrees, that's 10 degrees S of SW.
In the multiplex order BBCA/PSB1, D3&4/PSB2, BBCB HD/PSB3, SDN/COM4, ArqA/COM5, ArqB/COM6, COM7
Winter Hill UHF channels are -
The main multiplexes are C32, C34, C35, C29, C31, C37, C55
The Local ones are Local Manchester, Manchester GI on C24 & C27.
Liverpool Local mux on C21, Preston Local mux on C40.
I doubt whether you'd get ANY of the Local multiplexes (even only 18km from Winter Hill) as none of them are beamed in your direction, you are not predicted to get any, the Preston one is the only likely possibility IMHO.
One thing to check is that you don't have any HDMI cables close to any aerial or flylead cables especially if those flyleads are not double screened types. HDMI has been known to cause interference, especially to C55.
Is your downlead double screened coax?
| link to this comment |
Felim Doyle:
Reception can be quite variable around the Silverstone area, we really need her full postcode (or one of a very nearby shop or pub, etc) to look at predicted reception. But in general, one might even expect more than 72 channels unless she's in a particularly difficult spot.
| link to this comment |
David Colenutt:
We're on the DAB transmitter page rather than the Freeview one, never mind, the only relevant information that's of significance at present is the UHF channels for each multiplex.
In the order PSBs1/BBCA, PSB2/D3&4, PSB3/BBCB HD, the UHF channels are C25, C22, C28
Check in your TV's tuning section that those are the ones you are actually tuned to, retuning after power cuts or other weather events could have got you inadvertently tuned to another transmitter.
More than one transmitter may be receivable in your locale, but as you haven't given a full postcode we can't say if this relay will give you the best reception, or which way your aerial should point, other than that the rods (or squashed Xs) should be vertical.
With some of the weather conditions we've had in recent months it's a good idea to check that your aerial seems intact and pointing in the correct direction with the rods (or squashed Xs) vertical and that your downlead looks undamaged and isn't flapping in the wind.
Also check all you coax plugs, connections, flyleads etc, unplug connectors check for corrosion or other problems and reconnect them. Flyleads can be a common problem, try swapping them.
See what signal strengths and quality you are getting for the multiplexes (groups of channels) shown in your TV's tuning section, this might indicate potential issues with your aerial or downlead.
If you post the figures for each it may give us a clue.
Aerial misalignments, problematic connections, water ingress etc. can seem to affect reception of just AN individual or several multiplexes.
Who installed your booster and where is it located? How old, roughly, is your aerial installation?
Check that you don't have any HDMI leads close to any aerial or flyleads, especially if the aerial and flyleads aren't high quality double screened types. HDMI is known to sometimes cause interference.
If your problem is related to incorrect tuning, or a fault on your aerial system, adding a booster will not be of real help.
Over recent weeks, high pressure weather systems have periodically been accompanied by "Temperature Inversion/Tropospheric Ducting" where signals from distant transmitters in Europe or the UK are carried further than normal, due to the particular layers of the atmosphere. It causes interference to your wanted signals. This can result in changes to received signal strength and quality.
The problems can last for seconds, minutes ,hours, sometimes even longer. Do NOT retune, you are likely to just lose your correct tuning.
If this was the sort of problem you were having , and your reception is currently good, and you are correctly tuned, just post the postcode and strength & quality figures and we might be able to offer further advice.
| link to this comment |
James halsey:
Well bearing in mind that COM7 operates as a Single Frequency Network (SFN) and your location and aerial direction, that signal could be coming from Bluebell Hill or Crystal Palace or a combination of both.
None of which unfortunately changes the problem of interference to The Bluebell Hill Local mux on C21 from PSB1 on the Faversham Relay at Ospringe.
| link to this comment |
James halsey:
Sorry, didn't see your last before my last! Just happened to see your previous post and replied to that straight away. Because COM7 is an SFN, the transmitter information will be different and not identify a specific transmitter.
Unfortunately because there is no published list of Network IDs (that we've found) which identify transmitters, because Sittingbourne Stockers Hill also operates as an SFN, I doubt that the Network ID will identify that or Bluebell Hill.
| link to this comment |
Edward Slater:
Is that loop resistance down to the TV from the loft, or from the TV back to the aerial?
Has your aerial got a Balun? It maybe worth looking at the loop resistance directly at the balun and check the internal connections, there maybe an explanation there.
How long (roughly) is your downlead?
As regards signals from Sutton, polarisations can change in the near vicinity of walls, chimneys, roof tiles & etc. This is why, as I'm sure you already know, RF is often described as being a bit of a Black Art!
If you haven't tried, see if examining each UHF channel (say above 44) has any spurious signals on them. Using the TV tuning section, you can probably see the strength/quality by selecting it but without actually tuning it. There might just be something causing an issue.
| link to this comment |
Graham Woodthorpe:
When you say "interference", can you describe as best you can what it looks like? Is the picture going "blocky/pixellating" and freezing or something else? Does the sound break-up or make noises at all?
Has it been OK in the last 24hrs?
Can you say roughly which way (compass bearing) your aerial is pointing and whether its rods (or squashed Xs) are horizontal or vertical? Is it roof/chimney mounted or in a loft? Roughly how old is it?
Is it a booster/splitter (for more than one TV) - model number if you can, is it variable gain?
What filters are they and where did they come from?
If you provide a full postcode, we can check your predicted reception and if you can receive more than one transmitter, whether you are pointing at the best option.
If you look in your TV tuning section, possibly under Signal Strength or Manual tuning or similar, you should find the Signal Strength and Quality (or Error/BER) figures. If you could post those for each UHF channel for each of the multiplexes (groups of programme channels) that can also help identify any issues.
| link to this comment |
Michael Ellis:
In addition to what StevensOnln1 has said, in answer to you last question, I agree there's no need to turn it down to 77%, in fact 97% may well have been fine. What is important is the Quality figures if they remain at 100% then all is fine.
Over recent weeks, high pressure weather systems have periodically been accompanied by "Temperature Inversion/Tropospheric Ducting" where signals from distant transmitters in Europe or the UK are carried further than normal, due to the particular layers of the atmosphere. It causes interference to your wanted signals. This can result in changes to received signal strength and quality, picture and sound breakup.
The problems can last for seconds, minutes ,hours, sometimes even longer. Do NOT retune, you are likely to just lose your correct tuning.
If this was the sort of problem you were having , and your reception is currently good (and has been good for the last 24hrs), and you are correctly tuned, just post the postcode and strength & quality figures for each multiplex and we might be able to offer further advice.
| link to this comment |
Wednesday 2 February 2022 4:52PM
Scott bowles:
As you haven't given a full postcode, it's impossible to give a definitive answer. If the Stroud transmitter is the only one you can receive, as it's a Freeview "Light" transmitter is only has the PSB multiplexes and no COM multiplexes.
To answer more definitively, please provide a full postcode and information about which way your aerial points - rough compass bearing, (and its polarisation). Do you have any aerial distribution amp/splitter etc.