Channel 4 HD signal quality inferior

[gebbel]

I just noticed today that the signal quality on channel 126 is about half strength. On the other freesat HD channels, it is over 90%. PQ is still very good but just wondering why the difference?

 

[MovieFan60]

Strange, here in the NW of England I'm getting almost 100%

 

[Stiggy]

I just noticed today that the signal quality on channel 126 is about half strength. On the other freesat HD channels, it is over 90%. PQ is still very good but just wondering why the difference?

Channel 4 HD is on Eurobird 1 28.2 rather than Astra 2D 28.2, so if your dish is slightly misaligned you will see a difference.

I've got to realign mine

 

[davemurgatroyd2]

Channel 4HD is on Eurobird at 28.5 East and most other freesat channels are on Astra 2 at 28.2 East. There is also a difference in the skew required on the lnb for the two satellites. Correct alignment is a compromise between the two satellites both in direction and skew.

 

[Stiggy]

Sorry, my typo.

Any tips other than moving the dish a fraction more to the east?

 

[Mr_Fantastic]

Sorry, my typo.

Any tips other than moving the dish a fraction more to the east?

lol, yeah, get a better dish. And/Or LNB

Sky minidishes are quite poor and even a marginal size increase can still be within 60cm dimensions. Some sky dish fitters make a very poor job of fitting them being on such tight time constraints, being paid to get dishes up with little time or regard to maximizing quality.

I replaced a very old Sky minidish with a fractionally bigger FaVal (<=60cm) dish and Invacom Quad LNB and it improved my signal enough to make it very usable. Now everything works quite well on Eurobird 1 and Astra 2 although there still are a few channels where the quality is lower than I would like but several trees might be having a marginal effect on my signal.

I only have a PC Sat card to use to judge the quality and it shows the following percentages using the FaVal dish:
C4 HD 83-84
NHK HD 83
ITV HD 1920 83/84
ITV HD 1440 81
BBC One HD 81/82
BBC HD 81/82
Movies4Men 83
Movies4Men 2 83
True Movies 82
True Movies 2 82
Horror 81
Horror+1 76
CBS Action 77/78
Film 4 80
Film 4+1 80
True Ent 81/82
BBC1 W mids 79/80

These percentages are with an old set of drivers which give a better indication of quality because they don't just show 100%, they give a much more linear indication of quality. A new set of drivers just shows the quality as being 100% on all of them, meaning that any errors are correctable. The driver makers claim that anything over 80% means all errors are correctable so they started reporting quality as being 100% where quality was above a threshold of about 80%. But even channels which previously reported the quality as being below 80% such as 76% now show it as being 100% so the 80% figure isn't quite as absolute as they claim. The lower quality gives less margin for error during bad weather, it's currently bright sunshine outside.

I just fitted a bigger Penta 85 which I am playing around with, I just hope no one starts questioning planning issues where I have it.

 

[Stiggy]

I do have a larger dish. I think alignment is my problem. I'm told the larger the dish the harder it is to get it properly aligned.

 

[Bat-man]

C4HD with me about 20% worse than others on both strength and quality but picture and sound fine.

 

[Tight Git]

I do have a larger dish. I think alignment is my problem. I'm told the larger the dish the harder it is to get it properly aligned.

Correct, but you'd need an enormous dish to be able to differentiate between 28.2E and 28.5E.

 

[gbmitie]

did you try tweaking the lnb ie twist for skew and move in and out for focal length, what make of dish and size is it and what lnb are you using ie make and is it a quad or a single?

gb--

 

[Mr_Fantastic]

I do have a larger dish. I think alignment is my problem. I'm told the larger the dish the harder it is to get it properly aligned.

Bigger dishes are more awkward to align, I noticed the difference between my smaller 60cm Faval dish and my Fracarro Penta 85.

did you try tweaking the lnb ie twist for skew and move in and out for focal length, what make of dish and size is it and what lnb are you using ie make and is it a quad or a single?

gb--

The focal length can make a big difference to quality, it did on mine and there is a large amount of moment possible with my LNB. I got 10dBuV more signal just by moving the LNB towards the dish from where I had it to begin with and I still have some tweaking to do so more improvement is possible.

There is also quite a difference in skew for Astra 2A, B & D and Eurobird 1 so that could have quite an impact on signal quality.

 

[castalla]

My experience with a 1.9 m dish ... is that lnb skew is critical.