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Is there a 'good' time to retune?

Discussion in 'Freeview' started by Last.To.Know, Dec 28, 2016.

  1. Last.To.Know

    Last.To.Know Member

    Since the Olympics Retune, my BBC4HD reception has been terrible.

    Does the day or time of day one retunes in any way change whether one gets a good set of channels?

    (Yes, I am clutching at straws).

    Also, that thread stated that

    Did BBC4 HD stay on COM8?

    Also, any help/ideas with getting better BBC4 HD reception would be gratefully received.
  2. Owen Smith

    Owen Smith Active Member

    BBC4 HD went back to COM7 the same as it was before the Olympics. The COM8 information appears to have been completely bogus, it was never on COM8. Your BBC4 HD reception should be the same as it was before the Olympics.
  3. prpr

    prpr Well-Known Member

    No. You're probably on the wrong transmitter if it was OK before. But unless you provide the relevant information...
    No, that was duff gen.
    It was cetainly the plan at one point, but it obviously got changed.
  4. Last.To.Know

    Last.To.Know Member

    Thanks for the reply, prpr.

    I'm on Sandy Heath, or at least I should be.

    I did not know I had access to the Mux info in Web-IF till I just looked, but here it is:-

    Channel Frequency Signal Strength Signal Quality Network Mux Type Channels >799
    32 562.0 MHz Cambs & Beds COM7/ARQ C DVB-T2 (HD) 17 view 0
    or, just the text to reveal the Signal Strength and Quality:-
    32  562.0 MHz  27%  100%  Cambs & Beds  COM7/ARQ C  DVB-T2 (HD)  17  view  0
    You're right, BTW.

    BBC4HD is on COM7.
  5. prpr

    prpr Well-Known Member

    Well COM7 from the Heath is definitely on 32, so it's not that.
    Do you want to post the strengths of your other muxes for comparison purposes?
  6. Owen Smith

    Owen Smith Active Member

    27% seems low for signal strength, that could be the problem.
  7. Last.To.Know

    Last.To.Know Member

    Here are the muxes:-
    Channel Frequency Signal Strength Signal Quality Network Mux Type Channels >799
    21  474.0 MHz  36%  100%  Cambs & Beds  PSB3/BBC B  DVB-T2 (HD)  7 view  0
    24  498.0 MHz  40%  100%  Cambs & Beds  PSB2/D3&4   DVB-T  (SD) 11 view  0
    27  522.0 MHz  42%  100%  Cambs & Beds  PSB1/BBC A  DVB-T  (SD) 24 view  0
    32  562.0 MHz  27%  100%  Cambs & Beds  COM7/ARQ C  DVB-T2 (HD) 17 view  0
    34  578.0 MHz  29%  100%  Cambs & Beds  COM8/ARQ D  DVB-T2 (HD)  4 view  0

    I only record HD and listen to the radio so I only really use Channel 21 DVB-T2 (HD) and Channel 27 DVB-T (SD).

    They usually record perfectly, weather permitting.

    BTW I already use a signal booster, albeit one that's now a decade old.
  8. Owen Smith

    Owen Smith Active Member

    You should also have 48, 51 and 52 for COM4-6 and 40 for the Cambridge local mux (which you might not be able to get as it transmits at low power from the Maddingley mast). I write as a fellow receiver of Sandy Heath.

    Your signal levels still look low. Even PSB3 on 21 at 36% seems low to me. Where are you?

    Your "signal booster" may be doing more harm than good depending on where it is and what type it is. It needs to be fully screened and on the aerial. If it is an old analogue design and on the back of the TV you are probably better off without it. It is free and easy to try removing it anyway.
  9. Last.To.Know

    Last.To.Know Member

    I'm in Milton Keynes, in a dip.

    There is a green plastic box attached to the aerial mast which I think is the signal booster, or part of it.

    The rest is a freestanding (i.e. not on the back of the telly) white plastic box, into which the aerial cable goes.

    Tomorrow, I might experiment with turning it off.
  10. Black Hole

    Black Hole Theloniuos Abbot

    Costs nothing to try, of course, but having an unpowered amp in the aerial feed isn't likely to help the situation! The amp may have failed. It would be better to see what happens if you bypass it, but I guess that wouldn't be an easy operation (and uncomfortable in the current weather).

    For test purposes I would be trying a separate temporary aerial.
    Trev likes this.
  11. Owen Smith

    Owen Smith Active Member

    The green plastic box on the aerial mast is probably the masthead amp. The white plastic freestanding box is probably the power supply, if it has a mains lead going into it then it feeds power (probably 12V DC) up the aerial coax to power the amp. The aerial lead has to go through the power supply to feed power to the amp.

    Some amps pass through normally if fed no power, whereas others drop the signal.

    This might be a 4G problem, if the amp has been there for about a decade as you say it might have been fine all this time until a 4G 800MHz basestation was installed close to you. This could be overloading the amp. It's only a theory, did you get anything through the post or letterbox saying you might get 4G interference?

    Another option is the amp has simply failed due to age or water ingress or your cable is water penetrated. Age takes its toll on outside installations.

    Being in Milton Keynes you won't get the local Cambridge mux. But you should still get SD muxes on 48, 51 and 52. If you don't that's a bad sign, it means your reception is borderline. Can you try tuning them in?
  12. Luke

    Luke Well-Knwon Member

    That part of your analysis may be a bit of a red herring. Given that the aerial system is old it is very likely that the aerial is of type group A. Muxes on 48, 51 and 52 are significantly outside the group A reception range.

    Not if it is a group A aerial.
    Last edited: Dec 30, 2016
  13. Trev

    Trev The Dumb One

    Yeah. According to ATV aerial characteristics, the gain of a group A over about CH40 is zero. But that does not explain the OP's not very good signal level on CH 21-34, but might 'make a hole' in higher CH numbers
  14. Last.To.Know

    Last.To.Know Member

    Thank you for that, Owen.

    I remembered the postcard I'd kept from Let's Be Clear at 800.

    I went through their Diagnose Now tool, which made me think that may be an issue.

    I phoned them this morning and they are sending out an engineer tomorrow.

    Yes. Saturday. New Year's Eve. For free.
  15. Trev

    Trev The Dumb One

    Hopefully, he will be able to give you a pointer into what's wrong. But as others have said, it's probably not 4G, more likely an aerial or amp problem.
  16. Owen Smith

    Owen Smith Active Member

    But never mind, an engineer is coming out to look at the problem for free. Won't provide a fix for free if it's not 4G but at least the original poster will get an opinion from someone in the trade that hopefully has some clue.
  17. Owen Smith

    Owen Smith Active Member

    I realised the group A issue last night. But the original poster said the installation is about 10 years old, which is after Sandy Heath started broadcasting digital on high UHF channels. So either it's a digital spec system with a wideband aerial and hence could suffer from 4G interference. Or it's an older analogue spec system with group A aerial, which could be part of the problem as the aerial might not have a balun, the coax might be crappy "low-loss" analogue era rubbish, and the masthead amp and power supply would likely be unscreened which can cause all sorts of problems.

    So to my mind the lack of 48, 51 and 52 indicates a problem, either that it's an old analogue spec aerial system or that a digital spec system is performing badly.
  18. Last.To.Know

    Last.To.Know Member

    The engineer has just been.

    My old aerial amplifier was unshielded, he said.

    He replaced it with one that was shielded and filtered (I think?).
    He also added a new internal amp/filter/dongle to my aerial cable chain.

    He also made sure to note down it was a Humax HDR T2 as he said "they want to know what is affected (or not!)".

    He gave me an at800 card, on which he had ticked the box
    "Mobile signals (4G at 800 MHz) have not contributed to or caused disruption on your TV."

    I was not charged for his work or the new parts.

    Web-IF reports thusly:-
    Channel Frequency Signal Strength Signal Quality Network Mux Type Channels >799
    21  474.0 MHz  36%  100%  Cambs & Beds  PSB3/BBC B DVB-T2 (HD)    7   view    0
    24  498.0 MHz  40%  100%  Cambs & Beds  PSB2/D3&4  DVB-T (SD)    11   view    0
    27  522.0 MHz  42%  100%  Cambs & Beds  PSB1/BBC A DVB-T (SD)    24   view    0
    32  562.0 MHz  27%  100%  Cambs & Beds  COM7/ARQ C DVB-T2 (HD)   17   view    0
    34  578.0 MHz  29%  100%  Cambs & Beds  COM8/ARQ D DVB-T2 (HD)    4   view    0
    which is odd as the TV GUI has them all around the 60% mark.

    I've cleared the browser cache and still the same.
  19. Owen Smith

    Owen Smith Active Member

    Those signal strengths in webif are exactly the same as you posted previously, and the number of channels per mux are the same too. If the TV GUI is reporting 60% signal strength then that's correct, the question is what's up with webif.

    More importantly, has this work fixed your reception problem? You didn't say. Anyway at least you got it done for free.

    Does the new "internal amp/filter/dongle" have a mains lead going to it? If it does then it is the power supply for the new amp, it's generally not a good idea to leave an ancient one in use as it was probably also unscreened. Did he take the old internal box out of the aerial chain?

    Did he say whether your aerial is Group A or Wideband? If your signal strength is now around 60% you really ought to be able to receive COM4-6 on 48, 51 and 52, unless your aerial is Group A. Have you tried a retune, or tried just tuning in those muxes if you don't want to do a full retune?
  20. Owen Smith

    Owen Smith Active Member

    Ah, when you say the TV GUI do you mean the actual TV's tuner, or do you mean the Humax HDR Fox T2 GUI as displayed on the TV? If you mean the actual TV's tuner then that can easily be 60% when the Humax is showing lower figures, because this is a percentage of an arbitrary 100%. The 100% figure is not calibrated between different products, you can only compare figures with those measured on identical equipment.