Technical fault on some channels

Bigcheeze

Recently, my sky service is giving me blue screen "technical fault with this channel" messages on certain channels. Sometimes the error is "no satellite signal is being received". It seems to happen with channels 101-108 and the sports channels 401-40x. A couple of times i plugged out the box for a few seconds and this seems to resolve the problem but tonight even thst doesnt work. I haven't noticed it with other channels. Any idea what the problem might be ?

Sam the Aerialman

Bigcheeze wrote: »

Recently, my sky service is giving me blue screen "technical fault with this channel" messages on certain channels. Sometimes the error is "no satellite signal is being received". It seems to happen with channels 101-108 and the sports channels 401-40x. A couple of times i plugged out the box for a few seconds and this seems to resolve the problem but tonight even thst doesnt work. I haven't noticed it with other channels. Any idea what the problem might be ?

Go into Services 4-6 (Signal Test screen) What is the signal quality bar registering? Either the dish is slightly up kilter and blowing in the wind, possibly a slipped U bolt or the box is donald ducked.

Bigcheeze

Sam the Aerialman wrote: »

Go into Services 4-6 (Signal Test screen) What is the signal quality bar registering? Either the dish is slightly up kilter and blowing in the wind, possibly a slipped U bolt or the box is donald ducked.

Strength is a bit over half, close to two thirds. Quality is almost the full bar.
If the dish is off kilter would that not affect all channels ?

Sam the Aerialman

Bigcheeze wrote: »

Strength is a bit over half, close to two thirds. Quality is almost the full bar.
If the dish is off kilter would that not affect all channels ?

I have seen on many occasions dishes go just a hair off and some channels remain and some or lost. Channels are beamed down from the satellite in different polarisations - A classic one is the movie channels disappear because they are broadcast in horizontal polarisation. If the indicated quality is almost full i would say the encoding of the box is almost knackered. Its the boxes way of telling you its on it's way out.

Switch the box off at the mains for 10-15 mins - Start up and hold in the back up button for around 30 seconds. A black screen will appear and will
run a test and update the box. Could a nasty over the air update the box received and occasionally goes haywire.

iqon77

I had a similar problem... if you have a cordless phone unplug it when the problem appears.. I had the same problem on the E3, TV3, C4... the signal from the phone seems to mess with the sat.signal... hope this helps !

watty

DECT cordless 1.9GHz add 9.75 = 11.65GHz, add 10.6 = 12.5GHz
Those are the two sets of channels that will be lost

Check here http://www.lyngsat.com/28east.html to see if frequencies above are within 20MHz of any Transponder corresponding to damaged channels

It means you have sub-standard sat coax (poor screen) or a bad connection that lets the 1.9GHz from phone or base unit get into cable.

Bigcheeze

Interesting. I'll try unplugging the cordless later. I didn't fully follow your post watty. Are you saying I need to check for a loose connection on the coaxial cable?

fat-tony

Sam the Aerialman wrote: »

If the indicated quality is almost full i would say the encoding of the box is almost knackered. Its the boxes way of telling you its on it's way out.

Sorry Sam - you've lost me there - what does that sentence mean

Sam the Aerialman

fat-tony wrote: »

Sorry Sam - you've lost me there - what does that sentence mean

I was suggesting that if the box is registering 100% signal quality then the alignment of the dish is not at fault. Missing channels, freezing of the box, resetting the box by taking out the figure 8 lead is often a sign that the equipment inside the box used to encode the signal is about to fail.

fat-tony

Sam the Aerialman wrote: »

I was suggesting that if the box is registering 100% signal quality then the alignment of the dish is not at fault. Missing channels, freezing of the box, resetting the box by taking out the figure 8 lead is often a sign that the equipment inside the box used to encode the signal is about to fail.

You mean decoding of the signal - not encoding?
I have had a problem with a SKY+ box PSU which started to fail, resulting in odd problems. Replacing the capacitors in the PSU sorted the issue.
You were being a bit cryptic in your reply, maybe?

StewartJ

I had a similar problem turned out to be the head unit getting stuck on horizontal or vertical and therefore only picking up those channels until i switched the box off for a while then it seemed to work again for another period

fat-tony

Sam the Aerialman wrote: »

The NDS software that Sky use - A signal must be encoded before it is decoded. The signal is received by the lnb dropped a frequency, the transport stream is encoded by the box as the Sky signal it requires, is then presented to the box for decoding or modulating and reaches your television set. All done in a split second.

I wasn't trying to be intentionally cryptic i'm just very aware that not everybody is a satellite expert, like dealing with a customer at their front door.

Sorry Sam - but that doesn't make sense either. I'm aware that the video and audio streams are encrypted using NDS and need to be decrypted using the keys on the card etc, but this has nothing to do with signal quality / reception etc.
The transport stream, after being demodulated by the box, needs to be decoded from MPEG2/MPEG4 and decrypted - not "encoded by the box as the Sky signal it requires" ???

Your earlier post, which indicated that a full quality bar was somehow an indication of a failing box was confusing. We spend our time on these forums informing people that they should aim for as near a 100% quality bar on satellite and terrestrial digital reception.

Sam the Aerialman

fat-tony wrote: »

Sorry Sam - but that doesn't make sense either. I'm aware that the video and audio streams are encrypted using NDS and need to be decrypted using the keys on the card etc, but this has nothing to do with signal quality / reception etc.
The transport stream, after being demodulated by the box, needs to be decoded from MPEG2/MPEG4 and decrypted - not "encoded by the box as the Sky signal it requires" ???

Your earlier post, which indicated that a full quality bar was somehow an indication of a failing box was confusing. We spend our time on these forums informing people that they should aim for as near a 100% quality bar on satellite and terrestrial digital reception.

Apologies you're absolutely right when i read that back that sounded like utter nonsense i had written.

Bigcheeze

Just an update on this......I tried switching my Sky + box from the bedroom with the troublesome standard box downstairs to confirm if it was a box problem. The Sky + box worked initially but then started giving similar errors. So it looks like the problem was not with the box. I did the LNB reset as advised on the Sky website and the it seems to be working ok since then.


Edit: scratch that, the fault is back tonight.

ranger4

Could have a possible faulty tuner or problem with PSU.

fat-tony

Bigcheeze wrote: »

Just an update on this......I tried switching my Sky + box from the bedroom with the troublesome standard box downstairs to confirm if it was a box problem. The Sky + box worked initially but then started giving similar errors. So it looks like the problem was not with the box. I did the LNB reset as advised on the Sky website and the it seems to be working ok since then.


Edit: scratch that, the fault is back tonight.

That "LNB reset" doesn't do anything with the LNB as such. It just turns off some of the LNB settings in the SKY box and then turns them on again. The fact that the problem remained in the downstairs connection when you moved the SKY+ box to it would indicate that either the cable, the connection or the actual LNB on the dish arm is at fault. Does the "troublesome" standard box work ok upstairs?

Bigcheeze

fat-tony wrote: »

That "LNB reset" doesn't do anything with the LNB as such. It just turns off some of the LNB settings in the SKY box and then turns them on again. The fact that the problem remained in the downstairs connection when you moved the SKY+ box to it would indicate that either the cable, the connection or the actual LNB on the dish arm is at fault. Does the "troublesome" standard box work ok upstairs?

Yes it works ok upstairs. I guess its a dish problem as it only affects certain channels - Irish ones, sports, documentaries. BBC and sky news are never affected.

fat-tony

Your first post indicated problem with 101 - 108 and the premium sports channels. Your last post says that the Irish channels are ok - they are 101 - 104
If you can name several specific channels that are definitely affected, then maybe the problem can be isolated to the LNB or to external interference.

Bigcheeze

fat-tony wrote: »

Your first post indicated problem with 101 - 108 and the premium sports channels. Your last post says that the Irish channels are ok - they are 101 - 104
If you can name several specific channels that are definitely affected, then maybe the problem can be isolated to the LNB or to external interference.

No, last post says BBC and sky news are never affected.

Could it be that free to air channels are unaffected ?

Its also an intermittent problem. It's working normally tonight but wasnt yesterday.

fat-tony

Sorry - missed the full stop:o
The RTE radio channels are on the same transponder frequency (10743H) as RTE TV and TV3 TG4 etc. Check the RTE radio channels next time you have this problem. It's almost certainly nothing to do with the fact that RTE TV is encrypted as you would get a card error. The RTE radio channels are FTA, though, so checking those will eliminate a problem with decrypting the channels. Discovery / Animal Planet are on 11388H and SKY Sports 1 / 3 / 4 are on 11469H. BBC NI is on 10817V. You should compare the signal quality bar on the affected channels with the signal quality on the unaffected channels. The signal strength bar is pretty irrelevant - it quality you're looking for.

It's possible that you are just marginal on the reception of some of the Horizontal transponders, so it may be just a matter of adjusting the skew on the LNB. You do this by loosening the screw and rotating the LNB in its holder slightly one way or another and checking the signal quality on the affected channels - but not in this weather!

Booms

Doesn't the signal strength indication normally show a default channel, not necessarily the one with the problem?

I think you'll need to go into manual tuning (For a sky box: system, 4,0,1, select) and select manual tuning, then enter the required values to see the actual strength for that channel.

Might result in better skew setting on a marginal channel.

Maybe someone else can advise better?

fat-tony

Thanks for that - I'm forgetting that the SKY boxes show the S/S and S/Q on a default transponder. I can call up the S/S and S/Q on any channel on the Humax Freesat box which I've been using for the past two years!

Manual tuning as you outlined is the way to go to tweak a specific transponder:)

Bigcheeze

Ok rte radio does not work when I have this problem. I can't manually tune the affected channels either

Booms

Can you clarify that the box when it is upstairs is connected to the same dish?
If it is, and the boxes both work okay upstairs with no problems, the dish must be aligned properly

If so, then either one of your LNB outputs might be banjaxed, or the cable to the downstairs box needs to be checked carefully
Is the f-connector making good contact with the cable? Is the copper centre core of the cable still copper coloured, or is it black? (which would indicate water in the cable)
Is there a cordless phone unit positioned near the box, or beside the cable anyway along its path? Unplug it from the mains, and see if the problem rights itself, and if it does move the unit further away
Have you done any DIY recently that might have damaged the cable? Doesn't have to be cut, compression will alter the characteristics of the cable, and cause strange frequency dependant problems

If none of the above work you might have a spare output on your LNB that you could switch the downstairs cable to. If the dish is mounted high up, you'd be better getting a professional to look after it - he'll have equipment, experience, and insurance if he's from ISAA

My moneys on the phone

( Do wireless internet routers have the same effect?)

fat-tony

The frequencies affected don't indicate a problem with a DECT phone and the OP has been asked to check for sources of interference. The fact that the issue is with a series of horizontal transponders would indicate a possible issue with the particular LNB output (as you say) or some problem with the particular cable or possible a marginal reception problem which could be sorted out by adjusting the skew on the LNB. It's time to check out the dish / LNB alignment - professional is good advice if the dish is in an awkward location or OP is not willing or able to access.

Bigcheeze

Yeah both connected to the same dish. There is one output point free on the lnb which I could try. Does the cable just screw on?

Sky suggested a system update and failing that (which it did) a service call. am I better off getting sky to come out or someone independent?

fat-tony

The cables just screw on to the LNB with a plug called an F-connector. They may be covered with a little rubber boot (to keep out the weather) or the LNB may have a pull-down shroud which covers all four connectors. Just push this up to access the individual cables. Can you identify which one feeds the troublesome downstairs point? As booms suggests, you need to check the central core of the cable to ensure it's not blackened by corrosion / water ingress. While you're up there you can check the skew of the LNB unit. Depending on the model there may be a screw which locks the LNB in a particular orientation. Loosening this and turning the LNB unit slightly clockwise or anti-clockwise may result in the improvement of the quality received.

Booms

Oops! Sorry Fat-Tony - hadn't read your earlier post stating it was isolated to horizontal frequencies carefully enough

How does the cable to the affected room get there? Is the dish on the same side of the house? If not is it possibly thrown over the roof apex to get from one side to the other rather then clipped to the eaves/wall? This could cause wear and water ingress