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No TV signal in the middle of the night

Discussion in 'Audio Visual' started by StephenOak, 9 Jun 2020.

  1. StephenOak

    StephenOak

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    We have an indoor aerial which works fine, Crystal Palace is close - I regularly see the mast when I am out.

    A couple of time recently I have tried to record programmes in the middle of the night (1-3 am) and when I looked at them all that was shown was a message like 'Bad or no signal'.

    I was up late yesterday and so at c. 1am I looked and I had lost all channels, all of them just displayed that error message.

    The aerial cable connects to a PVR, which loops through to a second PVR and from there to the TV. I checked via both PVRs and had the same issue on both of them. This morning everything was fine.

    Any ideas what is causing this?
     
  2. Sureitsoff?

    Sureitsoff?

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    do any of the pvr's go to "sleep" overnight as a power saving method? also some tv's etc switchoff if no remote button is pressed for a time
     
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  4. StephenOak

    StephenOak

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    The first PVR in the chain (a Humax) already had 'Power saving in standby' set to Off. I can't see an RF out setting, but with no power saving it should be looped through.

    The second one had 'Power saving in standby' set to On from midnight to 6am, with RF out set to On. I don't see how this could cause the problem as this machine is second and I could see nothing when it was switched on. However I have now set 'Power saving in standby' to Off and will look tonight.
     
  5. Lucid

    Lucid

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    You probably need to spend a little time investigating because this isn't a simple "check the aerial plug2 sort of problem.

    Where I would start is by checking the signal late at night direct in to the TV. That means taking the aerial lead out of the PVRs and plugging it directly in to the TV, and making sure that the TV is correctly tuned. If you still lose signal late at night, then you've got an issue with the aerial system or TV, so you know you shouldn't need to waste time looking at the PVR box settings.

    For a TV to cause an issue, it would have to put power up the coax to knock out a remote powered aerial amplifier. I've come across this with some LG TVs in a couple of rare instances. Either the customer had gone through some menus and decided that turning any "helpful" features on would be a good idea, or the TV was changed and the default setting for Antenna Power was ON but no one checked or understood to check whether it was needed. There may also be the case of the TV firmware being updated and some settings returned to default rather than how a customer set them.

    Obviously with the above, it only really applies if you have an aerial amp, and it's hard to see how this would only affect things during a specific time, but it's still worth checking.

    While in the TV menus, check for any timer settings or timer recording settings. Again, this is just eliminating possibilities that are easy to tick off. Where the signal still goes off, and there's nothing from the above that's applicable, then there's a good chance that your system is picking up some local source of interference.

    You haven't gone in to detail yet about your aerial system; its age, condition etc so the following is simply the next step in a sight-unseen troubleshooting list.

    Digital TV is more prone to interference affecting the signal. Poorly-shielded coax such as old TV aerial leads or those inexpensive aerial fly leads with the moulded-on ends are a common cause. Maybe the aerial is past its best, and while picking up enough signal still to give a useable result, when the interference strikes it tips the balance just over the edge in to failure. Another possibility is that the system is over-amplified and the interference is again the straw that breaks the camel's back.

    Check through any connections and make sure that the aerial plugs are still fitted well enough to get a decent signal connection. Single-shielded coax can be a weak spot, so aerial systems with old coax should have the cable upgraded to double-shielded for digital. Use good quality all copper coax: Webro WF100, Labgear PF100, Nexans copper NX100. Replace any cheap moulded-end fly leads with ones made up from the spare coax. Look at the aerial wall plates if fitted. If you see just a simple 1" square circuit board with screw clamp terminals then it's probably unshielded too. Replace that with a shielded wall plate.

    Check this stuff out and come back to us with more info.



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  7. StephenOak

    StephenOak

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    @Sureitsoff? actually had the right answer.

    Neither of the boxes I am using was going to sleep but there is also a BT TV box that my wife got for free in order to access on demand services on the TV. About the time we got that we also got a new 'smart' TV that can access on demand services.

    So the BT TV box is wired up between the aerial and the first PVR, but is never used and is not very visible. And it was set (by default?) to go to Deep Sleep mode between 1an and 8am. So initially I completely forgot about it.

    Changing that setting resolved the issue. Thanks for your help.
     
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