Replacement for old Sky Minidish

[xer0w]

Hi,

I've been having issues with 'BT Sport HD' on Sky, whereby the picture breaks up and pixelates to the point of being unwatchable, it only happens on the BTHD channels, nothing else. Both Sky+HD boxes have the same issue.

I've had an engineer round to check over my system, dish realigned, cables checked but no problems were found.

I’ve spoken to both Sky and BT about the issue and they just blame each other for the problem.

So I decided to do some research on this myself, and the best solution I can come up with is to replace my Sky Dish and LNB as it's nearly 15 years old, although I can’t find out specifically why this would cause the problem, it has been suggested that it might be the cause.

I’m not too sure however, if I should just go with another Sky minidish or a standard 60cm dish? My thinking here is that if I’m going to replace my dish I’d rather get the best solution possible as its installed at height and costs ££’s to get the work done.

I live in Central London and some people have said a Minidish is all you need, others that a ‘proper’ dish would be better all round and in bad weather.

Any help and advice much appreciated.

 

[Lazarus]

The HD versions of BT Sport are very close to frequencies prone to interference from Cordless Phones.

If you have such a thing, try turning off the Base Station and see if the problem disappears.

 

[xer0w]

I have tried this previously as it was suggested on BT's own forum, but unfortunately it didn't fix it for me.
When I do see the issue it gets so bad that I get an on-screen message saying 'no satellite signal is being received', other channels are fine when I switch over.
I'm no expert, but I'd be surprised if interference from a DECT signal would cause a drop out?

 

[Analoguesat]

DECT is a common problem and its more than enough to knock out one or two frequencies and a whole bunch of channels on the affected frequencies!

 

[Lazarus]

Oh, believe me they can.

They work at around 1880 MHz: The signal collected by your LNB is downshifted by either 9750 or 10600 MHz to a band from 950 MHz to just over 2000 MHz.

Working the sums backwards, Interference from a DECT phone can affect Channels on Transponders around 11530 and 12480 MHz.

The interference exploits weaknesses in cabling and connections, including wall faceplates.

It's very common indeed.

BT Home hubs are another well known offender.

The effect is either bad pixellation or no signal.

I still think you might have an interference issue and suggest you turn off any and all telephone, WiFi or similar electronics to prove or disprove. If proven, a simple elimination exercise will identify the culprit.

 

[xer0w]

Ok I'll try it again when I get the problem, as I'd rather not go spending £200 if I don't have to.... Typically its working fine at the moment.

 

[Lazarus]

Don't forget the source might lie with a close neighbour.

 

[xer0w]

I'd also add that when I was dealing with BT's helldesk, they requested I check channel 376 (Bliss) when the problem occurs and see if its replicated on that channel (it isn't). Would this be because they share the same frequency (again.. I'm a noob on this subject )

 

[Lazarus]

Bliss is on an entirely different frequency (11307 MHz) to BT Sport HD (11603 MHz).

Can't think what they are hinting at - but the fact they have some potential answers suggests you are not alone in your experiences.

 

[xer0w]

Really appreciate your help with this, it's been driving me crazy... Glad I found this forum now

Assuming it is interference, would it be worth upgrading to a better quality dish and LNB? Or would this be pointless.
I understand there are many factors at play with interference, and it might be a combination of things... but I'd like to start somewhere.

Assuming of course it can be fixed at all.

 

[Lazarus]

If it's interference, it will be exploiting cable shielding weaknesses local to the interference source (See earlier comment about cables/joints/wallplates).

Changing the Dish/LNB won't alter that.

The answer is prevention (moving the interference source further away), or cure ( using better quality cable, eliminating any unnecessary joints and fitting proper double-screened wallplates (If any are in use)).

The Skybox itself should be immune as it is effectively a Faraday Cage (Google is your friend!).

 

[xer0w]

I don’t have any wallplates or joints, just two cable runs straight from the lnb to the back of each box; I've no idea what type of cable it is.

 

[Lazarus]

I don’t have any wallplates or joints, just two cable runs straight from the lnb to the back of each box;

But even humble RG6 should do.

 

[Riverblue]

WF100 will be good enough. WF125 is thicker and less flexible, also you would need larger F plug fittings to suit, WF125 is only needed with very long cable runs, say 40m plus.

 

[davemurgtroyd]

If it is interference - you need to determine whether it is at microwace frequencies which would enter at the dish/lnb and really could only be cured by relocating a dish so that it is shielded from that interference OR is it RF interference which would be entering the system after the dish through the cabling, wallplates or directly into the receiver. Merely fitting a new dish/lnb at the present site is unlikely to solve the problem although a significantly larger dish may have a narrower "field of view" and lower the interference if it is at microwave frequencies. What quality is your existing cabling - double screened braid and foil? Do you have wallplates fitted.

Sources of microwave interference include radar (military and civil). car radar speed detectors, microwave links (security etc), mobile phone masts and even street lights. RF interference includes WiFi devices (baby monitors, routers, DECT phones etc) and poorly designed heating/boiler pumps. These are not exhaustive lists but merely the most common/

 

[xer0w]

Ah right thanks. I think I'll try that route first with some WF100.

 

[xer0w]

Not sure about my existing cabling, I've attached a picture of the connector end and with a ruler. Diameter is about 7mm.
I've done a magnet test now and the core doesn't stick

I live in a populated area with many WiFi signals and everything else in between I'm sure.
I just hope I can at least mitigate this issue if not eliminate it altogether, I don't mind spending some money to do it, I just want to make sure I'm on the right track.

 

[skomedal]

Picture 1 ( cable end ) shows a poorly fitted F con.

Dielectric should fill the whole screw end to the stop area and be visible when F con. viewed end on.

Regards

 

[Lazarus]

Yes indeed - looks like it has come unscrewed a bit from the cable, possibly causing the sheath to make poor or intermittent contact.

That won't exactly help immunity from interference.

 

[xer0w]

Thanks guy's, I'll rectify that.