Help! I've lost channels and I can't work out why...

[Derf1969]

...other than that I'm a dunce and I've done something wrong, obviously!

I recently replaced a 43cm mini-dish with a 60cm Raven and a quad LNB supplied with the dish (it was local and cheap and I thought it would be easier to hit the right satellilte!)

Before the new dish, I was getting no signal strength on my Thomson DSI 4101 and about half quality and of course constant dropout and freezing at every gust of wind and drop of rain.

Now I'm getting about one-third signal strength and eight-tenths quality, but I'm missing some channels and still having poor reception on a couple of others.

Note, I live just north of London, so I was expecting much better performance than this from the new dish and obviously not expecting to have any missing channels.

The dish has been aligned with a compass and sat meter and, from everything I can see (UKSatelliteHelp.co.uk - UK satellite tv dish set up guides, software and news, neighbours' dishes) it's pointing in the right direction - but obviously, I'm willing to be told otherwise if it fixes the problem.

I wondered if the receiver wasn't switching polarity, but a check of the missing channels shows that they're a mix of both V and H.

From what I can tell, it's also running the latest firmware version.

Here are a sample of the channels I'm missing:

Sky 2
Sky 3
Living (& +1)
Living 2
Virgin 1 (& +1)
Bravo
Challenge
ParaComedy 1 (& +1)
ITV2 +1
Zone Romantica
Hallmark
E! Entertainment
TCM
FX+
Trouble (& +1)
Propeller
Disc RT +1
Disc RT Extra
Eurosport UK
Eurosport 2 UK
Motors TV
Sky News
Nat Geo Wild
Sky Sports Extra
Sky Sports News

I'm getting poor reception on:

ITV 3
VH1
VH1 Classic
TMF
Channel U
Film 24
Travel Channel +1

So, any ideas?

Am I pointing at the wrong satellite - close, but no cigar?
Has the ancient receiver given up the ghost?
Does the antique cabling that I inherited from the previous occupants need replacing?

Any and all suggestions and thoughts gratefully received

[Robbo]

Hi, are you actually seeing a picture on the channels identified with poor reception? Are they the correct channels?

If so, you are on the correct satellite.

Unless there is a receiver fault then you will have to check all the other likely problems, eg dodgy cable, LNB fault, dish alignment.

Try adjusting the dish while looking at the signal quality screen, to see if you can improve it.

Try replacing the cable, wiring direct from receiver to dish, with no joins or connection poins in-between. Ideally you want pf100 or wf100 CAI approved cable, you can normally buy short lengths on ebay.

Robbo

[Derf1969]

Hi - thanks for the quick response.

Yes, the channels with poor reception are showing the correct channels.

I'll maybe try replacing the cabling with something a bit better quality.

I hope that the LNB is okay as it's supposedly (and looks) brand new (but I know it doesn't always work that way... ).

I used a sat meter to adjust the alignment, so I'm not sure how I would go about improving the alignment.

Is it possible that I'm aligned to another satellite just off the right one and therefore getting the higher strength channels as "over-spill"?

[Robbo]

Yes, if you have not got the dish aligned properly, it is possible for adjacent satellites to cause interference on a small dish. However 28E is the strongest satellite in that area so 28E would still 'win'

To improve the signal, look at the quality meter on the screen while adjusting the dish, I assume that you have no obstructions to your line of site to the satellite?

[Derf1969]

The odd thing is that until the old dish was dislodged by a storm, we had no real problems with any of the channels, and that was despite having a really poor signal on a 43cm dish... Rain or wind would cause disruption, but it was otherwise bearable.

That's what makes me wonder if something's gone pop somewhere.

Are there any known issues for Thomson receivers losing signal strength?

I was intending to use the additional LNB feeds for a second box in the bedroom, so I may as well get one anyway and see if that has a better signal and all those missing channels.

[Robbo]

Well, you could try your box on a neighbours spare output if possible. Might help diagnose if the box is knackered.

I know little about Sky boxes, some of the old Grundigs developed power supply faults, but I've not read about anyone having problems with a Thomson, mine's been going strong for 5 years now.

Robbo

[nanochickin]

it was local and cheap and I thought it would be easier to hit the right satellilte!

It actually works the opposite way round. The bigger the dish the harder it is to align to the correct satellite. The bigger the dish the narrower the focal point becomes, hence its harder to get it in the right position

Sky mini dishes can be out quite a bit and still give a reasonably good signal quality. The same thing as above really, Sky minidishes have quite a wide focal point compared to the larger dishes

I would just setup a portable TV near the dish so you can see the digiboxes inbuilt Signal meter. I think its no 6 in the services menu although i may be wrong as i haven't used my Digibox in ages.

Just try moving the dish slightly to see if it improves the signal quality and also try adjusting the skew of the lnb. Just remember that on a Digital system Quality of the signal outweighs the strength of it.

Try and get the best quality level you can even if it sacrifices a bit of signal strength.

With regards to your digibox the only fault i ever had with a Thomson box was an unbearably load screaming noise through the TV speaker after Sky kindly updated the software on it for me. Never found what was wrong with it as i just binned it and purchased another el cheapo box off ebay the next day

I know some other digiboxes suffered from tuner problems but i'm sure that was one of the Pace or Panasonic boxes



Nano

[joekir]

Hi,

3 possibilites:
1. Double check the F plug connections at both ends...use an ohmmeter if possible.
Yes, the cable might well be at fault, especially if water has affected it and there are joins that are not waterproof. As you say it's antique, that's where to look first.
2. You don't mention the skew....might cause this problem with a marginal signal if the alignment is not spot on. Did you peak it up with your meter?
3. Try another LNB...they do fail in this way, sometimes because of water ingress or just bad luck. Also, some people report poor signals from Zinwell quads.

[Derf1969]

Excellent info gents - especially "larger dish does not = easier to point"! Counter-intuitive, but now that you say it, it does make sense

I think it might be time to entertain the neighbours with a portable telly out front to see if I can get a stronger signal, although, like I said, it's stronger now than it's ever been and with a higher quality too...

F-plug has been stripped-back a couple of inches at the LNB end, but I will try the same at the receiver end (the cable has no apparent joins and isnt' a long run - 10 meters max).

Skew has been tried across all the five positions available and right to one side definitely gives the best quality.

Actually, when I think on, I noticed something last night when watching the signal quality for a short while (obviously nothing much of interest to me on Sky then ) despite it being a very still evening and no rain, the signal strength was bouncing up and down from about from one-quarter to one-third and back again....

It's a proper mystery

Thanks again for all the assistance - very much appreciated.

[Derf1969]

In case anyone is following this sad saga...

Got increasingly poor picture quality through yesterday evening until a lot of previously watchable channels (Discovery, ITV, Dave) were dropping out and becoming unwatchable

As everything was tightened to the max, I thought it was probably LNB-sag so first thing this morning I was out adjusting the dish again.

Now it is continually saying "No satellite signal..." despite the compass and sat meter treatment! Can't get a Sky lock on, despite the sat meter screeching its little heart out when pointed where all the info says 28E ought to be!

As there are no riots in the streets, I have to assume that Sky are still broadcasting and that my system has now gone completely kaput

I'm out of the country for a week, but when I get back I think the old dish and LNB will be refitted to see if that isolates the fault to the new quad LNB.

Then a change of cable and possibly receiver.

After that, I quit