All posts by Chris.SE
Below are all of Chris.SE's postings, with the most recent are at the bottom of the page.
Dan T:
Hi Dan. My suspicion is it was most likely weather conditions as StevensOnln1 has mentioned COM7 is still being transmitted from Fenton. Whilst mobile interference can't be ruled out, you should have received a communication from "restoretv.uk" if a new mobile mast operating in the 700MHz band is likely to cause you interference.
There had been moderate Temperature Inversion/Tropospheric Ducting affecting large parts of the UK for several days (pretty well a good week IIRC), it sometimes accompanies high pressure.
In such conditions, do NOT retune, it will more likely remove your correct tuning. It may even leave you incorrectly tuned to distant transmitters whose signals then disappear as conditions change.
Essentially it results in interfering signals from other transmitters in the UK or Europe reaching you and so your wanted signals are disrupted, and of course ability to receive signals from transmitters further afield that are on different frequencies. It can/did also affect FM and DAB.
It won't necessarily affect all multiplexes or necessarily at the same time if more than one. It can last for seconds, minutes, sometimes hours or longer.
These conditions cleared the UK by Thursday morning.
Despite the incorrect spelling, this link does work - simple technical explanation
https://www.bbc.co.uk/rec….jpg
Since Thursday conditions seem to have returned to normal, so if you haven't tried a manual retune for C55 since then I would give it another go. Also make sure you don't have any HDMI leads close to your aerial or fly-leads (especially if the latter aren't double screened coax) as HDMI has been known to cause interference especially to C55.
What figures does the Freeview Detailed predictor give for your COM7, and does the BBC one say variable or good?
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Karl:
Hi Karl. Merry Christmas to you.
As soon as I saw mention of your Blake LP28A I realised I'd completely forgotten about that one, haven't seen it mentioned for a while. Blake make some good aerials. Having a loft mounted aerial will certainly drop the signal strengths, so as your wanted signals seem strong enough, it's obviously helped with the unwanted ones.
Your posting error is not an uncommon problem that the site owner has had since some software upgrades, but also posts sometimes take a while to appear, so wait about 5 mins and do a refresh before trying a repost (so ignore the error message).
You are lucky in one way that Winter Hill's main multiplexes are within Group A (UHF channels as mentioned in Winter Hill (Bolton, England) Full Freeview transmitter | free and easy ).
COM7 as you probably know will close by the end of June 2022 so probably no real sacrifice (dont' know what will happen to those channels yet). The one exception for your area is the Preston Local mux on C40, just outside Group A. I don't know how sharp the fall-off in response is on the LP28A, do you get any signal on C40?
Those signals you were getting on C24 & C27 were highly likely to be from the Rowridge transmitter on the Isle of Wight. All those local stations are on BBCA there.
Winter Hill also uses those two channels for the Manchester Local and Manchester GI muxes, but Local muxes are beamed in the direction of the areas they serve.
As you were getting Rowridge at the time, there might have been some quality degradation/increased errors on you PSB muxes. Mendip also uses C32, C34 & C35 for those muxes, they have been received in the Winter Hill region on similar occasion in the past.
If you are interested in Dx, see Sandy Heath (Central Bedfordshire, England) Full Freeview transmitter | free and easy and the posts before it. The sites mentioned are useful (as well as having some links) but also get familiar with your own set's strength and quality/error figures for your muxes. Changes there will also give you a clue about your local conditions.
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Russ:
C25 is the SDN/COM4 multiplex and is transmitted at the same power as the ArqA/COM5 and ArqB/COM6 multiplexes. These are the same power as the main PSB multiplexes if using vertical polarisation (200kW) but they are only 50kW in horizontal polarisation.
The Planned Engineering should have been completed and I can't find any faults reported.
There's also the possibility that you may be in a location where that multiplex is not predicted to be received as well as the others but we'd need a full postcode to check that, as well whether your aerial rods (or squashed Xs) are vertical or horizontal.
What signal strength and quality figures have you got for all the other multiplexes?
How long has this problem been happening, is it very recent, ie the last day or two? Or has it been a problem since the new LG, and how long is that? An LG set shouldn't specifically be a cause.
Have you changed anything else around in your installation? Check all your coax plugs and connections for corrosion, bad connections etc. Make sure you haven't got any HDMI leads running close to your aerial or flyleads as HDMI has been know to cause interference.
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Andy Falls:
When you say you have tried "everything", does that include a retune?
Which way (rough compass bearing) does your aerial point and are the aerial rods (or squashed Xs) horizontal or vertical?
There are several transmitters that could be received at your postcode. You should get almost perfect reception from the Angus transmitter to the ENE of you.
Have you checked that your aerial looks intact and is still pointing correctly?
Also check your downlead is secure and not flapping in the wind and that the coax looks undamaged and check all connections and coax plugs behind your TV.
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Andy Falls:
See my reply to you here - Get to see your Freeview predictions map | free and easy
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MR P Mayhew:
Well, the disappointing news for you is that it is going to change, BUT COM7 was only ever a temporary lower power multiplex and is due to close by the end of June 2022. There's been no announcements yet about what will happen to any of the channels on the multiplex. The main HD channels 101-105 are on the BBCB HD multiplex and that transmits at the same power as the other 2 main PSB mutliplexes so you should not be having any problems with them, your post is unclear as to whether you do.
Now if your aerial is pointing towards Sandy Heath (Anglia region), Bearing 104 degrees (almost ESE) with the rods (or squashed Xs) horizontal then the Freeview and BBC predictions are quite reasonable - variable reception which means it should be ok most of the time. Whereas if you aerial were pointing due N at the Waltham transmitter (Central East) you're predicted to get very poor reception of ANY of the COM multiplexes.
See Channel listings for Industry Professionals | Freeview for which channels are carried on which multiplex. (Note - there is no Local multiplex at Sandy Heath but there is a low power one at Madingley which is further away - you are not predicted to receive it).
A first check you could do is make sure you don't have any HDMI leads close to any aerial or flylead cables especially if the latter aren't double screened coax. HDMI has been known to cause interference especially to UHF C55 COM7.
If you are also having problems with the main HD channels 101-105, then this could be due to having too much signal as you've got 100% signal on all the other multiplexes. Apart from pixellation and sound breakup, the quality figure tends to reduce and weaker multiplexes will probably suffer first. If you have severe overload, the strength figure can appear to reduce as well when in fact it hasn't. If your amplifier(s) have a gain control, then try turning it down a shade so that the signal isn't 100% on the multiplexes.
If the amplifiers are splitters as well (feeding more than one set), try swapping outputs to see if anything changes but It's less likely that individual outputs go down, the whole amp may however. Try the aerial direct to one set without any amp/splitter and see what strength and quality figures you get for each multiplex.
Also just check all your coax plugs and connections, I assume you've checked your aerial looks intact and is still pointing correctly and that the downlead isn't flapping in the wind. Make sure there is no corrosion or water in the downlead at the plug end.
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Dan T:
Just one point of clarification, it doesn't matter whether it's 5G or 4G etc., it's whether it's transmitting in the 700MHz band. Some of those transmissions from some MNOs can be 4G. The MNOs coverage maps don't usually give an indication as to what band(s) a particular mast is transmitting on. There are some sources that do give some idea, but they aren't always up-to-date as they rely on users updating the data. Whether StevensOnln1 can tell us any good sites in that respect, I don't' know.
I would turn off any auto-retune where you can, it's more trouble than it's worth and there's no real benefit to it. If something changes on any of the COM muxes, you'll normally get an on-screen pop-up message telling you.
It might be worth just checking what sort of strengths you get with the aerial direct to one set, just as some sort of reference, can always be useful to check the amps aren't playing up as well.
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Karl:
It does sound like your set-up is working very well for you, and you choice of the LP28A was certainly wise.
I have been considering LPs for a while, for similar reasons, flat responses and impulse noise rejection not that I currently have any major issues with my current set-up.
When COM7 closes I shall revisit it so that I'm in a situation where I would be as future proofed as I reasonably could be, you don't know how things could change. Also whilst I'm not expecting any new mobile masts near me, especially on the line-of-sight, you can never be sure. Current masts are behind me and well to my right off the aerial beamwidth.
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tinman:
Ah, you've unfortunately fallen into the confusion between channel 64 - ie. LCN (location) 64 in the EPG and UHF Channel C64.
LCN64 is Freesports and it's carried on the COM7 HD multiplex which is on UHF C55 from the 25 main transmitters that still have it. BBC4 HD is on the same multiplex, it's LCN106.
See Channel listings for Industry Professionals | Freeview for which channels (programmes) are carried on which multiplex.
You can try a manual scan of UHF C55 (746MHz) but it's going to depend on which transmitter you receive. Even if it's a transmitter that has COM7, you may still not receive it as it's lower power than other multiplexes and you may not be in a location that can receive it (a full postcode would be needed to try and check that).
Also note that COM7 is (always was) a temporary multiplex which is due to close by the end of June 2022. There has been no announcements about what will happen to any of the channels carried on COM7.
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Friday 24 December 2021 2:07PM
Karl:
Hi. It would have been the weather conditions at the time.
There had been moderate Temperature Inversion/Tropospheric Ducting affecting large parts of the UK for several days, it sometimes accompanies high pressure.
In such conditions, do NOT retune, it will more likely remove your correct tuning. It may even leave you incorrectly tuned to distant transmitters whose signals then disappear as conditions change.
These conditions cleared the UK by Thursday morning.
Despite the incorrect spelling, this link does work - simple technical explanation
https://www.bbc.co.uk/rec….jpg
I would say you were possibly lucky that you didn't have any disruption to your normal multiplexes from Winter Hill.
Essentially it results in interfering signals from other transmitters in the UK or Europe reaching you and so your wanted signals are disrupted, and of course ability to receive signals from transmitters further afield that are on different frequencies. It can/did also affect FM and DAB.
I would guess that with reception of BBC Wiltshire you received one of the transmitters in the south of the UK. Without out looking up the channel numbers, I can't say which one of the top of my head.
It won't necessarily affect all multiplexes or necessarily at the same time if more than one. It can last for seconds, minutes, sometimes hours or longer.
The BBC had a warning on their Works and Warnings page for a few days, and Freeview had added one last Wednesday (better late than never!) but at the time it was then mainly affecting the S & SE.
As an aside, if your aerial is a log-periodic it won't be a group A as most are wideband, some newer ones are tuned/filtered to cut out signals above UHF Channel 48 (essentially Group K).
Does your Sony RDR-870 have a setting to auto-retune if it has no signal or receives new signals? If so, I would turn such a setting off as it can be more trouble that it's worth if your regular multiplexes are affected by interference.