Missing channels

We have three Freeview tellies, all Sony's. I live within line-of-sight of the Sandy transmitter mast - I can see the lights on it from the garden. And yet, we regularly "lose" channels. The main TV lost Ch28 (E4) this afternoon, plus several others I didn't bother making a note of. A retune has brought them back. The PVR has also lost Ch28, so I assume it's them rather than me (I can't retune it until it has no pending recordings, so that'll get done tomorrow.)

However, the one in the bedroom (which faces Sandy), which is on a set-top aerial is being even weirder. I had the "missing channels" thing a couple of weeks ago, so I retuned it, and now Ch's 2,3,4,5 & 6 are missing completely. In analogue days the signal was so strong in this room we didn't need an aerial at all...

So, what's going on? And how do I get my missing channels back?

Reply to
Huge
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This is where the experts hang out

Reply to
newshound

As it is Freeview then uk.tech.digital-tv might just possibly be an even more apposite group.

Reply to
Robin

Ta.

Reply to
Huge

To answer this, see the thread I just cross posted from uk.tech.digital-tv

Note you are due another retune event on the 9th of next month.

You may need to wait for all the muxes to go to full power, failing that you need a better aerial for it.

Reply to
John Rumm

No signal all day at our house - but I borrowed a gizmo from our sparks, a DB-T signal meter made by SLX. This typically says we have 70dBuv, but the set-top box resolutely says "f*ck that".

The chain is at present aerial cable -> set-top box -> scart -> 1994 Panny. Solution: new telly (most likely, haven't got it yet)

Reply to
Tim Streater

En el artículo , Huge escribió:

The signal's too strong.

Firstly, if you have an amplifier, take it out. If that doesn't help, get a couple of in-line attenuators, suggest 6dB and 12dB. Try one, then the other, then both in series. I had to do this with my Topfield PVR which points at Winter Hill but was picking up channels from Moel y Parc after they increased signal strength following switch to digital.

These are the ones I got:

6dB:
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you could try this variable one (I haven't used it):

quote: "Greatly reduces interference caused by excessive signal strength."

watch for line break on that last link.

Reply to
Mike Tomlinson

Well here in Crystal Palace land we have had to put an attenuator in the lead to get the channels to behave. I wonder if some tuners are not happy with the huge signals now and create cross modulation to some degree, ruining the quality of the signals?

Brian

Reply to
Brian Gaff

In article , Brian Gaff scribeth thus

Seeing the way their made and the price of them I rather doubt they would have spent much on the dynamic range handling of them and they skimp in other areas too;!..

Reply to
tony sayer

Oh, great.

BTW, how does one get to find out about these events? Not so much for me, but it means we have to visit my 94 y/o MIL and retune hers, since she struggles to change channels, never mind retune the damn thing. She lives in N13, I assume that means her telly comes from Aly Pally.

I suspected as much. I suppose I'd better plumb it into the main aerial the other 2 TVs use. Means getting up in the loft. :o(

Reply to
Huge

It all worked fine after DSO which was last year some time.

The sitting room (TV & PVR) & kitchen (Digibox) are fed from a distribution amplifier from an aerial in the loft. The bedroom is on a "set top" loop aerial. Given that Sandy is ~15 miles away and plainly visible from the bedroom window, I'd be amazed if the bedroom telly isn't getting enough signal. Are tellies deaf as posts? (I used to work the Sandy amateur radio 144MHz repeater on 4W to a "rubber duck" inside the house - what's Sandy put out? 25kW or something?)

It looks like the sitting room/kitchen is a simple "retune required" since they're still fiddling with the muxes there (thanks, John Rumm). Not sure what the bedroom one is. The symptoms look like insufficient signal strength, which surprises me. (Sandy is horizontally polarised and loop antennae are polarised in the plane of the loop, right?)

Reply to
Huge

I shall experiment, thanks. I can take the active splitter out and replace it with a passive one.

But that doesn't answer the problem with the bedroom TV which is on a simple inside loop aerial.

Reply to
Huge

All the digital box's I have seen have a signal strength function and a signal quality as well. This is good for the problem you have to try and quantify it. Have a look in the tuning settings.

Reply to
Gary

Ooh, good idea. I shall try that almost immediately.

[Time passes. Wavey lines.]

Sorted!

The PVR just needed retuning, but wouldn't allow it with recordings outstanding. Without any recordings outstanding, it retuned fine.

The bedroom TV needed retuning also, but the menu option you need to use is conveniently called "Auto Startup" (which I had foolishly assumed was something to do with alarm clocks) and not "Digital Tuning", which is what I'd previously been choosing. I assume the former throws away all the old settings and starts again, whereas the latter just looks for new services.

I am getting old. I can no longer operate my own TV. Grrrr.

Reply to
Huge

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you enter a postcode and it will tell you when...

Quite likely. That also switched over recently. (Although I no longer use that Tx, the event was highlighted by the arrival of a former neighbour on the doorstep to tell me he has lost ITV. (which he had not actually lost, but it had moved to the BBC2 frequency)

Given your proximity to the Tx, as others have said, too much signal may be an issue with the TVs on the main aerial. For the portable - its anyone's guess.

Reply to
John Rumm

When you said it's visible I can see the light on it and you didn't need an aerial plugged into your bedroom TV, I assumed that you are about a mile or two away not 15 now!...

You sure that Sandy had a 144 MHz repeater I thought that was Barkway around a few miles east of Royston?..

TV its now on most all MUX's 200 kW..

Well there're settled down apart from the odd retune thats coming up. We're not having any problems here in Cambridge some 19 miles distant ..

Well there're polarised in all ways and more;-)..

Seems that you still might have an overload on an aerial and amp 'tho its difficult to say over the net. You could see if you could borrow a known good box from elsewhere tuned to the Heath or take your box around a friends thats got known good reception?..

>
Reply to
tony sayer

Thanks all, but it seems it was "just" "them" fiddling with the muxes combined with finger trouble by the idiot user (FX:waves)

Reply to
Huge

[tap, tap, tap]

Ahh, you need the "trade view", then it tells you about retuning events. A tad obscure ...

Tell me about it. Changing TVs is a very traumatic event for a confused

94 y/o.

Finger trouble.

:o)

Reply to
Huge

You will have to nab the next passing 8 yo you spot ;-)

Reply to
John Rumm

Oh well, keep the manual handy. There is another change to Sandy due on

9th May which will require a retune if you want to keep ITV3, 5*, 5 USA etc.

The Com4 SDN mux moves from UHF Channel 31 to channel 51 and increases power from 20KW to 170KW

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Reply to
UnsteadyKen

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