BBC Four HD
Intelligent, idiosyncratic and provocative perspectives on every subject, for people who think differently.Main TV standard-definiton channels
How to Watch: BBC Four HD
High definition channels
| Channel name arrow_drop_down | web | radio | Freeview | Sky | Freesat | ||
|---|---|---|---|---|---|---|---|
| BBC Four HDaccount_box | live_tv | 106watch_later | 116watch_later | 108watch_later |
Regional content: National channel with no regional content or variations.
media.info: For full details of broadcaster contacts, see the
media.info BBC Four HD page.Official site: See the
BBC Four HD website.From Wikipedia: - en.wikipedia.org
read more about BBC Four HD on wikipedia (summary by Clipped).Freeview multiplex: BBC Four HD is on multiplex PSB3 in
.Monday, 6 April 2020
S
Steve B5:13 PM
Many thanks Chris, I'll try all of that tonight and post the outcome.
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Tuesday, 7 April 2020
S
Steve B6:13 PM
Hi Chris, thanks for your in-depth advice. I followed it all, but, alas still no Freeview Channels between 105 and 200. Those channels that are working have a signal strength of 100%.
I've now connected an additional TV to a separate aerial sockets, with the same results.
Pretty sure the signal to my house is good; I got 71 channels with the aerial disconnected!
Forgot to mention that the aerial feed goes thru' a Signal Booster/Splitter, which is an added complication. I'm going to bypass the splitter in case that's the problem, but it's odd that the problem started when the changes were made on the 20th Feb at Winter Hill.
If this doesn't shed any light on the problem, I'll have to change the aerial, but not sure which one I should get. Covid19 problem has delayed the next Winter Hill change that was due this April.
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C
Chris.SE9:53 PM
Steve B:
Try connecting the aerial direct to one feed for a single TV and see what happens. The fact that you are getting 71 channels with the aerial disconnected does imply the signal is very strong.
It could be that the additional signal from UHF C32 is causing overload somewhere (remember the old PSB1 mux on C50 is still simulcasting - channel numbers 751 et seq. so those will very old Group C/D aerials that won't receive C32 have a period of time to get the In Home support for the aerial change - which is the primary cause of the need to delay the final changes as the In Home support is difficult or impossible with the social distancing requirements).
If the gain on the booster/splitter is variable, try turning it down a touch, otherwise you might need to experiment with an attenuator (you can get a variable one for ~5 on eBay). Try moving the aerial around in the loft if that's possible, even just changing the bearing slightly if nothing else is practical.
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MikeP
10:14 PM
10:14 PM
Steve B:
A signal strength of 100% is too much and will cause problems, that may be the cause of your problems. You need to reduce the strength to between 70 and 85% ideally. You may need to try fitting an attenuator to reduce the signal levels.
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C
Chris.SE10:50 PM
MikeP:
We have been through this argument before, the 100% is NOT ALWAYS too much and won't necessarily "cause problems", and is what he had before (if you bothered to read his original post and he has no problem with the other muxes), it's a totally arbitrary figure dependent on the set manufacturer and he doesn't necessarily NEED to turn it down to your arbitrary figure of 70-85%.
I do suspect though that there is now some overload with the "extra" mux still broadcasting, which is why I suggested he experiment in the manner mentioned. The overload may be desensitising things sufficiently that the weaker COMs 7&8 are not getting decoded, but he needs to prove that by carrying out the suggested checks.
There is no point in continuing to refer to arbitrary 100% and 70-85% figures of a meaningless whatever signal level that's not a defined standard that all set manufacturers use. If it is overload, he'll need to reduce the signal to an undefined level that restores satisfactory reception of all muxes.
Aerial direct to one set is the first check to carry out. Simply moving the aerial - (maybe slightly off-beam) may also be a solution. As you well know RF can be a bit of a black art at times.
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Wednesday, 8 April 2020
MikeP
11:13 PM
11:13 PM
Chris.SE:
In my considerable experience in the TV industry, 100% is ALWAYS too much. Get used to the idea of being wromng sometimes.
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Thursday, 9 April 2020
N
nobody12:48 AM
MikeP: 100%? Of what? Steve B said "Those channels that are WORKING have a signal strength of 100%"
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C
Chris.SE1:05 AM
MikeP:
My experience says there are so many instances I have encountered where it says 100% and presents no problem. It's 100% of an arbitrary figure, so get used to the fact that your arrogance is not appreciated. I'm not the only one on this site who has challenged this ridiculous claim of these arbitrary figures based on their experience. If you'd simply said you agreed with me that signal overload was a likely possibility instead of yet again posting such meaningless figures, there would be no argument. Furthermore, for the sake of making a point, if the signal was turned down to 70% on the strongest muxes, this may put the signal of the weakest muxes below a decodable threshold (off the cliff edge). It's simple, if overload is the issue, then the signal should be reduced JUST SUFFICIENTLY so that all muxes are receivable without issue, not some meaningless arbitrary figure. Indeed if front end saturation was happening, even with the signal reduced it may still say 100%, a lot depends on front end design. Don't bother to argue the point any more, you'll get the same response.
Steve B:
As I said previously, if the gain of the booster/splitter is adjustable, experiment by turning it down a bit, what the strength figure says is irrelevant (within reason), a consistent 100% quality figure is the primary aim. Try the aerial direct to one set as it's unlikely that this will cause overload, but see what you get. If that manages to get a signal on mux 7 &/or 8, then try tweaking the aerial position/bearing to maximise the COMs7&8 signals.
Then re-connect your standard set-up, if you then lose COMs 7&8 then it's clear that overload is causing the problem, get that variable attenuator, I found this one reliable in the past - eBay item number: 310160230552
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MikeP
9:59 PM
9:59 PM
Chris.SE:
100% leave no leeway for variations in signal streng5th and many tuners are not able to deal with excessive signal strength. Hencw the advice to not have 100% strength. If you do have then there can be occasions when the atmospheric absorption reduces (less moisture for example) so the strength increases. If there is no leeway then that often results in loss of signals. So keeping it well below the limiting strength is far better than risking having too much. It has been so since the days of analogue transmissions and it is actually more critical with digital transmissions. Knowledge of RF transmissions and what affects them is vital,
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C
Chris.SE10:21 PM
MikeP:
How dare you lecture me about RF transmissions as though you are the only person on the planet that knows about these things.
As "nobody" has said "100% of what", as you clearly don't seem to understand what I've spelt out already.
YOU (nor I) know what 100% means on a variety of receivers, IT'S TOTALLY ARBITRARY depending on the design, you do NOT know if it is THE limiting strength. In some instances it WILL mean no Margin (poor design), in others they may be plenty of Margin. Each installation needs to be considered in its own right. Just get over it.
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