We just had some TV cabling redone and an amplifier added, so thass prolly where the issue lies, but I'm seeing NO SIGNAL reported for most Freeview channels - except I can get BBC Parliament and all the radio channels on Freeview. If say the new amp was on the blink I'd expect none at all.
I'll be calling the installer tomorrow, but I wondered if anyone else had seen anything similar. Transmitter is Dover (freeview.tv reports no problems there).
I would hazard a guess that if you had a good signal before the dingbat installer has either left something unconnected or has left a whisker of copper wire from the cable screening shorting out the signal. I'd start by disassembling and checking all the plugs. Also try connecting direct without the amp.
Tim
I'll have to figure out how to do that on my Grundig set top box.
Terrestrial (hence Dover transmitter :-)
Oddly, it's all come back now. We dint do nuffink honest Guv (except watch an episode of the Good Life on DVD).
The set top box showed signal levels higher than they were before, for channel 81 (BBC Parliament) and non-zero for all the others (as opposed to zero).
I take the point about an intermittent bit of copper but when it was away, it was away solid, and it's come back solid.
I need to pin down the times of when it does this.
The installer (actually our electrician) measured signal levels and said that the amp restores signal (some 10dB, is that right for a typical amp you'd have in the attic?) after attenuation caused by extra cable I asked for (we've got a longer cable run now than before because I want to be able to (a) have the amp easily accessible in the loft and (b) have the amp somewhere that I can tap off it later).
Can I ask another TV question? Anyone having probs with a Panny TH42PX70? It switches itself maybe from AV to HDMI or TV etc etc, when it does this the remote becomes VERY slow, many seconds. After a while it switches off then on again and is fine until next time.
This is totally misleading. He says 'Freeview' for one thing. And mentions that the transmitter is at Dover, not up in space. And it's bollocks anyway.
Bill
you are receiving one MUX out of 5.
mislaigned aerial, wrong aerial for the band or most likely a bad connection and reflections in a cable.
BTDTGTTS
AIUI you've had extra cable installed, and on the end that's remote from the aerial an amplifier has been added.
Technically, the best place for the amplifier is as close to the aerial as you can get.
What may have happened is the signal for one mux has, due to the new cable, degraded less than the others, and that's the one you're seeing.
Try bypassing the amp and seeing what happens.
Another problem might be mismatching of impedances giving rise to standing waves on the feeder. One mux has just the right wavelength/frequency to have a signal peak at the amplifier or TV. Altering the length of the feeder cable might help.
Can your system report signal-to-noise ratios as such (which might be better than 'quality'), or perhaps Viterbi data? You could monitor these while making changes.
Terry Fields
What is this MUX of which you speak?
Well I'm glad someone's awake.
Did I mention it came back last evening? Well, gone again this morning.
I did wonder whether he'd wired the amp power via the CH supply for the pump motor or something, but after the CH went off this morning still NO SIGNAL.
Anyway the lad's coming round today some time. He's local so knows he can't screw it up.
In message , Tim Streater wrote
List of TV channels on each MUX
MUltipleX.
Freeview has just 5 'stations' or 5 frequencies but each 'station' carries up to 25 channels that are digitally MULTIPLEXED together.
you are only receiving ONE of the five - the one that carries what you are getting.
That is a shorted cable or an open circuit cable somewhere - giving standing wave reflections and nulling out all but one station.
Eeeeiiiioouuuwww.
Could still be the amp I suppose. But let's see what Our Garry has to say later.
Meanwhile I have:
NOT_FOUND_ERR: DOM Exception 8: An attempt was made to reference a Node in a context where it does not exist.
to sort out.
Normally that sort of fault affects one or at most two muxes only. The usual (boring, simple) reason for reception of less than the full number of muxes is that they are at different strengths at the aerial terminals and all then suffer roughly equal attenuation for some reason or another.
Bill
well a good place to start is here to see what is on waht muxws and at what strength..
A strong possibility then is that it's the result of UHF propagation conditions being 'up' recently, during the sustained period of high pressure we've just had. The signal strength being up but the quality down does tend to point to it being co-channel (or even adjacent channel) interference from another transmitter.
A problem with digital is that it gives you little or no clue why reception has failed, unlike analogue where it was usually possible to recognise the type of interference (etc.) causing the problem.
I don't use jquery or any other such library. Turned out I was trying to appendChild(p) to a document fragment where p was null.
That's been my theory about what we've been seeing recently. Seriously degraded signals in the evening, but still high signal strength.
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