My Humax Forum » Freeview HD » HDR FOX T2

Intermittent COM7 and COM8 channels on HDR FOX T2

(11 posts)
  1. grahamlthompson


    special member
    Joined: Feb '11
    Posts: 10,280


    ZenSlo - 45 minutes ago  » 
    I am aware that the UHF signal is analog at the masthead.
    I am aware that the term “digital aerial” (which I did not use) is meaningless.
    You have made two suggestions for the cause of my specific problem (thank you).
    Your first suggestion was that the aerial signal to my Humax was too strong. I think this is improbable given that with my old aerial (with no masthead amplifier) my signal strength/quality (as measured by my Humax) was 5/10 on COM7 & COM8 and I had the problem.
    Your second suggestion was that by using a masthead amplifier I was distorting the signal by “clipping” it in a way that produced exactly the same problem I was having with my old (un-amplified) aerial. Again I find that improbable.
    Both of your suggestion fail to take into account the fact that my TV can display a perfect picture on the same signal that my Humax claims to be “no signal”.
    Does anybody else have any suggestions?

    Getting fed up with this. Amplifier design is a compromise . You can make a amplifier that is very sensitive. The output waveform follows the input over a limited range. If the signal level exceeds the linear response limits at either end the output waveform of the is distorted by either chopping off the peaks or the troughs resulting in a waveform with either the positive peaks chopped of at a constant level.

    This is the basis of amplifier design I learned at about 18 (now 74).

    The TV that works on your system could be either have less sensitive tuners or simply further from the aerial with the longer coax runs being sufficient to keep the input levels within the linear response levels of the tuner front end amplifier even with a log 36 in my loft.

    I can assure you that mu HDR-FOX-T2 tuners have a rock solid signal some 30 mls or so from a relay transmitter.

    I have amplification at the aerial but only enough to recover the numerous passive splits to feed multiple tuners. Even so I need to reduce the signal level to around 60%.

    Both take account of the difference between your TV's. It's the fact that you don't even understand the basics of analogue signal level amplifiers that's the issue.

    Mentioning the fact that it's digital TV has no relevance at all.

    Sorry but I am out of here. Trying to help, if you aren't prepared to try any suggestions I have nothing further to add.

    Good luck with resolving your issue.

    Basically a spectrum analyser would be needed to find the source of the problem.

    one thing is certain, the HDR-FOX-T2 is arguably the best Freeview+ box Humax ever made. Any reception problems is going to be down to your end.

    Basically seeking too high a signal level. Digital TV can cope with low signal levels to produce a perfect picture thanks to the built in error correction. At DSO the digital signal power was increased to a point where anyone that had high gain aerials ans amplifiers could and should have removed them.

    Try removing HDMI interconnects from other kit close to the RF cabling.

    HDMI cables can radiate in the UHF range and create issues.

    Replace all RF interconnects with double screened satellite grade cable. Ideally Webro WF100.

    Throw away any wall outlet plates that are not fully screened.

    Lastly read this

    Thu 29 Nov 2018 22:27:07 #11 |

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