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Thread: 100% signal strength and quality until 7:30 at night

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    Unhappy 100% signal strength and quality until 7:30 at night

    Hi Guys,

    I have 100% signal strength and quality, but for some reason at random times during the day, usually a night, the signal quality drops to 0% for an hour or so.
    Signal strength never drops below 100% when its happening. Any idea what this may be? We had an electrician and a technician come out to look at it.
    They replaced a bunch of cables but had no real idea.

    Cheers!



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    It very easy to have a 100% signal strength and 0% quality if the transmitter is running with no programming.
    You need to check around you (neighbors) to see if others are experiencing similar problems to eliminate the possibility the problem is with your equipment.

    Does this happen on all channels or only some and what transmitter are you receiving your signal from?
    What is your situation in relation to the transmitter, ie close or distant, clear view or 'obstacles' in the signal path?
    Last edited by gordon_s1942; 04-09-16 at 01:24 PM.
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    Firstly, where are you located and which transmission site are you receiving your TV signals from?

    Are you using any type of signal amp/booster?

    It's difficult to tell what your real signal levels are when given as % rather than in dBuV and quality in BER/MER, but when you have readings as high as you have, suggests you may actually have too much signal, causing overload, which is why I asked about amps, etc.

    It reception cuts out regularly at 7.30 suggests there is some device on a timer, or is manually used at that time that generates interference.

    A signal amp will also amplify any interference.

    More info needed to try and help.

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    Thanks for the quick reply guys.

    You need to check around you (neighbors) to see if others are experiencing similar problems to eliminate the possibility the problem is with your equipment.
    I have been in touch with 3 or so of my neighbors but unfortunately they all run satellites / don't watch free to air.

    Does this happen on all channels or only some and what transmitter are you receiving your signal from?
    Typically it happens to all channels some being worse than others. I'm not 100% sure on the the transmitter my LG and other TV's won't pony up this information. Is there somewhere I can find this out?

    What is your situation in relation to the transmitter, ie close or distant, clear view or 'obstacles' in the signal path?
    Again not too sure sorry.

    A signal amp will also amplify any interference.
    Definitely no new gain amplifiers or anything like that. My antenna and everything has not changed. We got the cables replaced thinking maybe some water was causing it but alas it didn't do anything.

    It reception cuts out regularly at 7.30 suggests there is some device on a timer, or is manually used at that time that generates interference.
    Yea this was my first thought, nothing internal from my unsteranding. I spent a couple of hours running the tv without anything else plugged into any socket into the house, including wifi / everything else.
    I should also point out that it usually happens at 7.30 but it can happen at 8 or 9. Very occasionally during the day I'm told but very rare.

    Completely stumped on this one. The probability that it is something external seems high to me but I'm not an expert. I guess something could of happened to the antenna placement or the cabling.
    Last edited by nomadxxx; 04-09-16 at 08:17 PM. Reason: words

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    You haven't answered my first question... where are you located?

    Where is your antenna pointed?.... some locations may be covered by more than one transmitter, which is why I need more info.

    Do you have any wireless devices in your home that get turned on around the time you lose TV reception? Room/baby monitor, computer, modem, etc?

    Any electrical device that gets turned on around the time of reception loss... including LED lamps, electric fences, radio equipment?

    What type of antenna are you using? Posting a pic will help if you don't know.

    Do you only have one TV antenna outlet?... if not, how many?

    You say the neighbours you've asked only have satellite..... do they have a problem with terrestrial reception?

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    Quote Originally Posted by gordon_s1942 View Post
    It very easy to have a 100% signal strength and 0% quality if the transmitter is running with no programming.








    My old Panasonic plasma shows this when the WIN Tx loses its programme input. It also only requires 35dBµV at the antenna input of the set to give a 10 on signal strength.
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    Quote Originally Posted by Antennaman View Post
    It also only requires 35dBµV at the antenna input of the set to give a 10 on signal strength.
    Excellent example... 35dBuV is insufficient to get a lock, let alone reliable reception, so without accurate signal measurements, it's almost impossible to determine what's happening.

    Which is exactly why a % reading means jack.

    You can have ten tuners, all the same make and model, and you'll likely get ten different readings.

    There could be any number of contributing factors, so the more info we get, it may (or may not) give clues to something obvious.

    If the OP has had a technician out, it would be extremely helpful if that tech could provide all the digital readings obtained.

    Hopefully he had a digital meter and knew how to use it..... but sounds doubtful from the OP's post.

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    Quote Originally Posted by mtv View Post
    35dBuV is insufficient to get a lock, let alone reliable reception, so without accurate signal measurements, it's almost impossible to determine what's happening
    My instrument, & many TVs/recorders I come across, will work happily forever with signal levels of that magnitude, providing no further impairments arise.



    As mentioned, the OP needs to provide more information about his location & setup.
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    To check your location out, got to , type in your address and it will show you whats available in your area.


    If that link doesnt want to load, type the address into the browser yourself.
    Last edited by gordon_s1942; 05-09-16 at 03:06 PM.
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    From AS 49331.1:

    "B10.1 Antenna input sensitivity
    The minimum signal level, measured in 75 ohms, over which the receiver is able to tune
    and correctly decode DVB-T signals shall be as follows:
    For 64-QAM, 2/3 code rate—
    VHF Band III –81.5 dBm (27.5 dBμV)
    UHF Band IV and Band V –80.5 dBm (28.5 dBμV)
    For 64-QAM, 3/4 code rate—
    VHF Band III –80 dBm (29 dBμV)
    UHF Band IV and Band V –79 dBm (30 dBμV)
    For a method of measurement refer to Clause B3. The quoted values for receiver sensitivity
    are for PFP1 measurements, not for QEF criteria.
    NOTE: The minimum receiver input levels were derived using the following relationship (but
    have been rounded to an accuracy of 0.5 dB):
    Pmin (dBm) = (10 ×log10 (kTB) + 30) + NF + C/Nmin – Delta . . .
    where
    k = Boltzmann’s constant = 1.38 ×10–23 J/K
    T = reference noise temperature = 300K (27°C)
    B = system noise bandwidth = 6.657 MHz
    NF = noise figure of receiver (dB) (Table B1)
    C/Nmin = C/N threshold (Table B2)
    Delta = 1.3 dB (Refer to Paragraph B3.2)

    For example, for a receiver operating in a Gaussian channel environment in Band III:
    For 64-QAM, 2/3 code rate case with C/N = 18.9 dB . . .
    gives
    Pmin = –105.6 + 6 + 18.9 – 1.3
    = –82.0 dBm (27 dBμV)
    For 64-QAM, 3/4 code rate case with C/N = 20.4 dB
    gives
    Pmin = –105.6 + 6 + 20.4 – 1.3
    = –80.5 dBm (28 dBμV)
    NOTES:
    1 0 dBm = 108.8 dBμV (rounded after conversions).
    2 0 dB NF represents –105.6"
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    I don't know of any tech that would be happy to walk away from an installation, leaving a customer with signals of the absolute minimum.

    Anyhow, the OP hasn't even visited the site since his last post.

    There's also the possibility of signal levels being too high, causing overload... especially when DCP is quoted as being 100%.

    It's quite possible this may be one of those cases that can only be solved by being there with test gear, but some more info as requested from the OP would help us to help him.

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    My favourites over the last few months are LED downlights... heaps of them are crap and cause problems on one or many channels .

    Also LTE, it's everywhere and getting worse, have seen around 90dbUv of LTE off a band 3 antenna in one situation, anywhere there is a wideband amp there now needs to be an LTE filter in front of it... Am getting a couple every week.

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    Quote Originally Posted by beeblebrox View Post
    My favourites over the last few months are LED downlights... heaps of them are crap and cause problems on one or many channels .

    Also LTE, it's everywhere and getting worse, have seen around 90dbUv of LTE off a band 3 antenna in one situation, anywhere there is a wideband amp there now needs to be an LTE filter in front of it... Am getting a couple every week.


    Same here.

    I mentioned LED lamps but the OP didn't answer my question.

    I'm also finding the need to fit LTE filters in many instances, one in particular was over 100dBuV of LTE due to an LTE tower only a short distance away in direct line with the broadcast site.

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