Occasional picture interference - on 2 installations

[Grmblwd]

Hello,
I have 2 satellite dishes one at each end of the house (35m between them)
One has a Sky dish and the other is a 60cm dish, both have a Humax Foxsat-HDR television recorder, both upgraded to 1TB HDD, and both have a 4 way LNB's with only 2 of the 4 being connected.
I have been having a problem with the Sky installation where the picture is messing about occasionally. I get some pixilation, scribble, ghosting etc.
It started about 2 months ago, and I assumed it was a neighbour's tree causing the problem and he kindly chopped 10ft from the top, clearing the line of sight.
The problem still occurred so I checked the LNB and found the front cover had broken (been in service since 2007) So I replaced the LNB and re-made the connections on both ends of the Co-axials, (there are 2 connections) and it is still happening.
I swapped over the Humax boxes, but the problem still persisted, so I assumed the Humax boxes were OK.
The other 60cm installation has no line of sight problems but is now playing up and appears that both installations have faults at the same time.
I replayed a recording made of the same programme on both the boxes, and they each had faulty pictures at the same place in the recording, but were not the same level of fault.
I have had no problem at all since I installed the systems in 2007 and both had 95% Signal strength and 90% Signal quality. This now sems to fluctuate where both LNB1 and LNB2 signal goes off and comes back on again, and the levels fluctuate.
I would guess it happens maybe for a second or two and very sporadic on the time interval.
I cleaned both dishes, checked the alignment and both are good.
I know weather has a part to play with rain causing disruptions, but in the past the rain had to be torrential to cause a problem.
I have some technical knowledge, but do not consider myself an expert.
Thanks for reading this missive.
Any Ideas of what may be the cause?
Regards

 

[jeallen01]

I'd be far more inclined to suspect the cables immediately near the receivers! The RF ones really do need to be high quality double-screened coax, like WF100, AND properly terminated with decent connectors in order to considerably reduce any cross-coupling between the cables from the 2 dishes!

OR possible inteference from the cables connected to other equipment in the vicinity?

O

 

[ozumo]

Does the interference coincide with anything like a fridge or boiler pump switching on?

 

[jeallen01]

Does the interference coincide with anything like a fridge or boiler pump switching on?

Certainly seen exactly that interferring with a mate`s hifi system a long time ago!

 

[Grmblwd]

As I said the installations have been in place for 16 years without any problem until early June. The particular recordings referred to were for 1 hour and within that period the interference lasted about 6 seconds.
I can watch for 3 or 4 hours with no interference at all, so I don't believe it can be related to the connections, or else why is there periods with no problem?
There is/are no new appliance/s operating.

 

[PaulR]

What sort of environment are you in? Are you in a town or country location? Has there been a new mobile phone mast erected recently? Anything else changed at a neighbour's perhaps?

 

[sonnetpete]

Wasn't there something similar to this a while ago caused by DECT cordless phone interference?

 

[Grmblwd]

I am in rural Brittany, with the nearest phone mast about 6km's distant, and there is nothing changed within the local area.

 

[sonnetpete]

I am in rural Brittany, with the nearest phone mast about 6km's distant, and there is nothing changed within the local area.

I think the problem manifested itself with cordless phones connected to your land-line.

 

[Channel Hopper]

Hello,

I have been having a problem with the Sky installation where the picture is messing about occasionally. I get some pixilation, scribble, ghosting etc.
.......Any Ideas of what may be the cause?
Regards

Ghosting ?

Can you take a picture next time it happens ?

 

[Grmblwd]

We have had VOIP since 2008, so don't have a landline as such as all calls are made over the internet.
The only explanation of ghosting is where the image has a matching shadow around the object/person, so maybe shadowing is a better description.
Will try to get a picture.

 

[dmaavrigdo]

We have had VOIP since 2008, so don't have a landline as such as all calls are made over the internet.
The only explanation of ghosting is where the image has a matching shadow around the object/person, so maybe shadowing is a better description.
Will try to get a picture.

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[PaulR]

We have had VOIP since 2008, so don't have a landline as such as all calls are made over the internet.

VOIP is irrelevant in this. It's been delivered along the copper wires to home until a recent push for fibre. So, if you're still on ADSL or VDSL then you are using a phone line. Within the house, unless you're using an old style fixed telephone, there will be DECT cordless portables in in use surely?

A further thought. Just possible you're using satellite or a wireless broadband? Please confirm.

The only explanation of ghosting is where the image has a matching shadow around the object/person, so maybe shadowing is a better description.
Will try to get a picture.

Maybe haloing would be a better description? Is tis permanent or does it come and go?

 

[scopus]

I take it both dishes have direct cabling from the LNB to the receivers? Nothing inline, switches, splitters etc?

 

[Grmblwd]

I do have cordless phones in the house, and as they also have been in use since 2007 I don't understand what would happen for them to cause a problem. They are all operating normally.
I am on ADSL through the telephone system of France, with 2Mb/sec broadband which again I have used since 2005.
It is raining today and I have had severe disruption of the signal shown on attached photo, so I am going to assume the problems are with the weather.

 

[Grmblwd]

One system has direct cabling, and the other has 1 direct cable and 1 with a connector which I have re-made the ends.

 

[scopus]

One system has direct cabling, and the other has 1 direct cable and 1 with a connector which I have re-made the ends.

Can you run a new temporary cable from the dish to one of the receivers just to eliminate any cable issue? Odd the same thing is happening at the same time on both the receivers..More likely some sort of airborne or even mains interference I would guess..Could you even borrow a different make of receiver to eliminate that?..

 

[Captain Jack]

BTW, don't discount Humax boxes being at fault. A lot of them have failing PSUs due to being kept warm or just age/poor components. A PSU recap fixes all manner of problems there.

 

[jeallen01]

Can you run a new temporary cable from the dish to one of the receivers just to eliminate any cable issue? Odd the same thing is happening at the same time on both the receivers..More likely some sort of airborne or even mains interference I would guess..Could you even borrow a different make of receiver to eliminate that?..

Quite likely - especially on oldish receivers where the conducted immunity may have deteriorated over time.

OTOH, any chance it could be anyone starting an old car, old petrol mower or something similar with an old petrol engine? - the suppression on old petrol engines was often poor.

Edited: Could even be from the starter motor of an old diesel engine!

 

[scopus]

Quite likely - especially on oldish receivers where the conducted immunity may have deteriorated over time.

OTOH, any chance it could be anyone starting an old car, old petrol mower or something similar with an old petrol engine? - the suppression on old petrol engines was often poor.

Also, has the neighbour had anything new?? Heat pump, perhaps, anything like that?