My Humax Forum » Freeview HD » FVP 4000T, 5000T

Picture freezing and pixelating on

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    IanWest

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    I've just replaced an HDR2000T with a refurbed FVP-4000T. Two reasons... 1/ I thought the 2000T was faulty and 2/ I wanted added features in the FVP. The fault I suspected is actually identical on the new box too. When playing through the box, I am frequently getting momentary freezing and pixelating of the picture. Sound is not affected. I got a TV engineer out yesterday and paid £78 just to be told my signal was 'perfect'. On all three tuners I get >87% Signal Strength and 100% Quality. I do not get the issue when playing directly through the TV. In all other respects the 4000T is behaving fine. Someone has suggested that my signal may be too good (really) and is overloading the tuners. Can that be right? Any other suggestions please. How do I solve the problem?

    | Thu 6 Apr 2017 9:49:35 #1 |
  2. Barry

    Barry

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    Welcome to our Forum

    There is anecdotal evidence that signal being 'to good' can cause issue but I have 100/100 without any issues.

    Other possibilities:

    HDMI cabling routed close to antenna feed, router located close to unit?

    | Thu 6 Apr 2017 10:13:24 #2 |
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    Martin Liddle

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    IanWest - 33 minutes ago  » 
    I got a TV engineer out yesterday and paid £78 just to be told my signal was 'perfect'. On all three tuners I get >87% Signal Strength and 100% Quality. Someone has suggested that my signal may be too good (really) and is overloading the tuners. Can that be right?

    It is certainly possible and I have seen it myself. I would suggest investing in a variable attenuator for the aerial feed to the Humax and see if it helps.

    | Thu 6 Apr 2017 10:25:52 #3 |
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    IanWest

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    Thanks for the feedback. I've just fitted an attenuator. Now need to monitor the box to see if it helps. I was wondering what level (strength %) to take it down to. Can't see anything in the manual to indicate minimum signal strength. I've currently got it set at +/- 70%. Any suggestions please.

    | Thu 6 Apr 2017 11:52:05 #4 |
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    Martin Liddle

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    IanWest - 4 minutes ago  » 
    I've just fitted an attenuator. Now need to monitor the box to see if it helps. I was wondering what level (strength %) to take it down to. Can't see anything in the manual to indicate minimum signal strength. I've currently got it set at +/- 70%. Any suggestions please.

    Signal strength readings tend to vary between the different Humax boxes. On an HDR-FOX T2 anything above 30% works for us but we are quite close to a transmitter; I would say 50% is a very safe lower limit. If the box is performing OK then increasing to 80% would be a reasonable limit but much better that you experiment. In a similar situation to you on a HDR-2000T (in a different location) I found that reducing signal strength to about 80% vastly improved performance but the final fix was to change the amplifier so that I could reduce the gain and remove the attenuator.

    | Thu 6 Apr 2017 12:06:24 #5 |
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    IanWest

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    Thanks again. I'll start low and work up. I'll let you know how I get on.

    | Thu 6 Apr 2017 12:13:14 #6 |
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    IanWest

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    Well, I wouldn't have believed that too good a signal could be the source of the problem. But, I've set it down at 50% and the Humax works just fine, and the problem is no more. I have a separate take off from the aerial down feed going directly to the TV so not using loop-through. As it works fine at 50% I am going to leave it there.
    Thanks for your help Martin.
    BR Ian

    | Tue 11 Apr 2017 13:43:14 #7 |
  8. grahamlthompson

    grahamlthompson

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    IanWest - 1 minute ago  » 
    Well, I wouldn't have believed that too good a signal could be the source of the problem. But, I've set it down at 50% and the Humax works just fine, and the problem is no more. I have a separate take off from the aerial down feed going directly to the TV so not using loop-through. As it works fine at 50% I am going to leave it there.
    Thanks for your help Martin.
    BR Ian

    The more sensitive the tuner the easier it is to overload the input. The tuner needs to output a faithfull copy of the input which requires a linear response from the lowest to highest signal level. If the signal input is too high the peaks are clipped resulting in a distorted output which causes issues. If the signal level is excessively high the signal level measuring circuitry can actually show a lower signal level. In this case attenuating the signal can actually increase the indicated signal level.

    | Tue 11 Apr 2017 13:50:31 #8 |

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