SKY +/Digital signal quality/strength ??

Discussion in 'Sky Digital TV Forum' started by rsvman, Jul 19, 2004.

  1. rsvman

    rsvman
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    What should the average signal quality/strength be ??

    I know different areas have different values.. is there a sky map that show expected strengths etc..


    ALSO...

    Anybody know where to get a cheap satellite dish meter , for aligning up the dish etc..
     
  2. Starburst

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    If the system is well installed you should be looking at max levels for both strength and quality however due to minor but cumulative issues anything around three quarters is good. The higher the reading the better although in good/clear weather that is less important but when the weather is bad with rain/snow cover the drop in signal reception requires that you have a lot of leeway to compensate.

    There is very little difference in signal strength when you consider the size of the UK and the overall footprint of the satellite coverage. However in bad weather northern and western locations can and do go for a Zone 2 (60cm?) dish instead of a standard minidish, this gives them the leeway I mentioned before.

    Coverage examples..

    Astra 2D
    Eurobird

    As for the sat meter perhaps Satcure.
     
  3. rsvman

    rsvman
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    Thanks for the reply..

    The reason for the question, was that on sky setting signal/quality is about 50/40 and during some programs where fast action is on screen, especially during the euro football and some motorsports, i would get ghost/trailing images when the person passed the ball or was running..i watched on normal terrest. channel bbc1/itv rather than through sky (bbc1/itv) and i did not get this ghosting/trailing image ??

    Also this weekend we had a heavy downpoor and we actually lost the signal..


    Could this be due to the low signal ..??

    My setup is sky digital through rgb to component to Denon 3803 into pionner mx plasma..i even by passed the Denon with no difference..

    I live around the stansted airport area (N.London).. so i would expect a good sky signal ..
    Does sky have a list of expected signal strengths/quality for each area in the uk (counties etc) ??

    Any advise would be welcome..



    Any advise would be welcome..
     
  4. stevebez

    stevebez
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    Rvsman - I am curious how your converted RGB picture compares to composite or S-Video? I am contemplating doing the same but it sounds like you are not getting the performance that the suppossedly better quality RGB / component should provide si not being realised.

    Rgds Steve
     
  5. rsvman

    rsvman
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    Steve..


    The sky digital has scart-rgb outout, so the only way to put it through the denon was via rgb-component JS box.. this does work fine as i did have my older dvd player going through this as well...hich was fine..

    Differences between the outputs ... depends on the input ie source.. if the sky broadcast is crap, then you'll get crap out..

    I think in thi scase maybe with some of th estrong winds we've had the dish has moved slightly out of line, thus giving me a poorer picture.. it snot frosty or anything, just when fast moving sports like football /motor-racing. the rest of the normal programs are fine...
     
  6. Starburst

    Starburst
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    The signal strength readings are on the low side and I am not surprised you lost the signal when it rained as the water absorbs/masks the signal and eventually the tuner can not see it.
    A dish realignment would probably sort that out.

    The "ghosting" you are seeing is more to do with the less than perfect bitrates and encoding that is evident on all digital platforms, the use of a larger screen (both CRT, LCD and Plasma) just amplifies that effect.
    An analogue source is not compressed and has strict quality regulations, the move to digital broadcasting has been corrupted by broadcasters who have used it to save money, no problem as such but not at the expense of picture quality. DVD's which use the same mpegII compression proves that the technology is quite suitable for domestic broadcast telly.

    The signal is coming from a satellite in geo-stationary orbit above the equater, the distance between London and Nottingham (for example) is insignificant in regards to reception. The actual installation and quality of the components will make far more impact on the final results than the location of the house the dish is bolted on to.
    The exception to this is far northern and western locations which as I have said sometimes require a slightly larger dish to compensate for a slight drop off in signal power and the issue of heavy weather redusing it even further.

    I would suspect that re-aligning your dish will solve part of your problem and might just improve picture quality slightly if the decoder does not have to use much error correction although that isn't a given.
     
  7. rsvman

    rsvman
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    To fine tune the dish, is moving the x/y axis needed or adjustment of the LNB ??
     
  8. Starburst

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    Might be worth adjusting the LNB first to see if there is any difference in the reported signals strengths but I would expect the dish itself is slightly out of alignment. It has been quite common that the heavier Quad LNB (compared to a single) causes the arm to droop very very slightly which can affect the reception.
     
  9. rsvman

    rsvman
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    Tried adjusting the dish and Lnb last night.... no difference ??

    The signal/quality is still 60/40...

    What next .. cables ??
     
  10. Starburst

    Starburst
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    I am surprised you couldn't increase the strength readings at the very least, you do have a clear line of sight to the satellite, no trees or tall buildings close by?
    Worth remembering that the dish can be moved in the x/y axis and also the LNB "skew" can be adjusted (clockwise/anti clockwise) also the LNB itself can be moved along the arm to alter the focal point.

    The quality of the cable will certainly have an impact on the ability of the LNB and tuner to communicate which makes using a sat meter even more useful so you can test the dish without relying on the cable/digibox figures.

    It may be worth investing in the e-book from Satcure which covers SKY D installation for the amateur, it certainly will help with the finer points:)
     
  11. rsvman

    rsvman
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    I tried the x/y axis of the dish and the z axis of the LNB but no diff.. but i did not try the rotational axis of the Lnb (skew) as the Lnb slider is flat rod.. ie will slide but not rotate..

    Line of sight looks ok, close to a building but not obstructed..

    I was looking at a meter, but so many comments about using the digital meter on the sky box (ie. under settings /system test etc..) is better, i didn't buy one..

    The cable has been there for around 12 years, so i suupose it could have deteriated..?? i have the sky mini dish .. would this cause the lower readings ??

    It would be nice to have a list of peoples signal strength/quality .. this would see what the average should be..

    I have just purchased sky+ with a quad Lnb, so i think i will replace the cable, when addng the other cable for sky+ and see if this makes a difference..
     
  12. Starburst

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    Twelve years old is quite old for a cable:)
    I would most certainly replace that with some two runs of good sat cable (CT100) or if you prefer the shotgun cable (CT63).

    A standard Zone1 minidish (42cm) is perfect for England, if it's installed correctly you should have 99.9% reliability, if you prefer you could go for a Zone2 dish or even an normal oval but beware certain LNB's are matched to a particular dish type.

    SKY+ (version 1).
    Input 1...........80/80
    Input 2...........70/80

    PACE 2200
    Input 1...........60/70

    The readings are taken from the default transponder, they should not be regarded as accurate for channels on the other satellites.
     

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