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How useful is a Sky satellite signal booster?

Discussion in 'Sky, Sky+, Sky HD & Sky 3D' started by Steppenwolf, Jun 24, 2008.

  1. Steppenwolf

    Steppenwolf Member

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    We moved out standard non-HD Sky Digibox to the new annexe recently. That room is quite far from the Dish and the Sky Guy had to put in a very long (over 100 feet) cable to connect it to the box. As a result, the picture and to some extent the sound quality are poor, despite a good resolution TV.

    Maplins have an in-line satellite signal amplifier that is supposed be useful for such cases and boasts 20dB gain. It is economical at £12 and I am thinking of getting it (or a similar device depending on your suggestions). Plase advice if this booster really does improve the AV quality or if there are better options.
  2. fernandez

    fernandez Member

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    It seems that an inline booster will do nothing to improve actual AV quality.
    On a long cable run they can be useful to overcome signal losses but, having said that, if the signal received by the box is sufficient and there is no picture break-up or pixellation there is probably nothing to be gained with an inline booster.
    With digital the signal is either strong enough to give a picture or it isn't.
    As an example if the signal and quality readings were say 60/70 you would see no improvement if they were 80/90. Have you checked these?

    This from Satcure http://www.satcure.co.uk/tech/cable.htm

    "How long can a cable be before loss of picture quality occurs?

    This comes under the category of "how long is a piece of string". Basically, there's no answer unless you know the input signal level and the minimum output signal level required. You can then work it out by looking at the loss per metre. For our cables, the loss is about 13dB/100m at 470MHz (typical UHF) and around 27dB/100m at 1750MHz (typical satellite LNB frequency). SATDS is fractionally worse. So, if your UHF signal is only just high enough and you decide to add, say, another 46 metres of cable, you'll need a 6dB amplifier to compensate for cable losses"

    How is your TV connected to the receiver and what type of TV is it?
  3. Steppenwolf

    Steppenwolf Member

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    The TV is a new 37" Toshiba 37AV505D HD Ready one. We do not have HD in this room yet, but the standard box was moved from the main room where it used to give good pictures. But the guy who came to do the installation of Sky HD in the main room and move the old box to the aforementioned annexe room was very unimaginative and took the long route over the roof to reach the dish even though there was a shorter route thru the garage.

    I have complained to Sky and they are sending a Special Services and higher height certified engineer this Sunday; he is scheduled to spend upto 3 hours with us if necessary and among the many options suggested so far:

    1. Moving the satellite dish to a higher position on the chimney stack where there will be no interference from swaying trees (an occasional problem with high winds)

    2. Shortening the cable route from the new annexe to the dish by cutting through the garage. If the dish is mounted on the chimney, it will be a bit closer anyway.

    3. Getting the aforementioned or similar signal booster.

    4. Getting a bigger dish. I am not sure if this is an option or even going to solve the problem.
  4. skytecbvmo

    skytecbvmo Member

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    The Toshiba 37AV505D is a new tv that you never used with the old sky box bring your old tv into the room where your old sky box is and i bet it will be fine. :smashin:
  5. fernandez

    fernandez Member

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    Most options seemed to be covered there and with #4 (bigger dish), the Sky Zone2 60cm mini-dish would certainly give more margin in poor weather conditions if that's a problem.
    It'll be interesting to know the outcome and I'm sure you'll keep us informed.

    Could you explain more on "...the picture and to some extent the sound quality are poor..." i.e. breaking up/pixellation or lack of detail/unclear/fuzzy.
    What are the current signal/quality strength readings on the Sky box?
    • Thanks Thanks x 1
  6. Steppenwolf

    Steppenwolf Member

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    Thanks Fernandez. Picture and sound loss (pixellation and break-up of picture, brrrr type sounds) occasionally occur with high winds in all 3 TVs connected to the dish including the HD, presumably due to the tall, slim trees that sway a lot. Although the dish in the present position is looking between two such trees, winds can sway the trees in its way. Mounting the dish on the dummy chimney should solve that problem because it is higher than the treeline.

    The blurry picture with 'ghosting' of the images is a problem only in the annexe with the Toshiba plus the old standard box. I presume that this is because of the long (over 120 feet) cable length to the dish. There is a way out of this as well by cutting thru the garage and maybe a 20db gain booster.

    The Sky guys said that the signal strength is good in my area. My neighbours say the same and so it must be true.
  7. fernandez

    fernandez Member

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    There is no way that lack of signal strength can cause "..blurry picture with 'ghosting' of the images..."
    With digital you get a viewable signal or you don't - it's that simple. Ghosting is purely an analogue effect on actual received signals
    Pixellation and break-up of picture, brrrr type sounds are probably caused by *temporary* signal loss/drop due to blockage from the swaying trees in which case mounting it on the chimney will help as far as this (and signal) is concerned *but not* picture quality
    Check the signal/quality reading on the box that's giving you problems and, as skytecbvmo suggested, try another TV ( CRT if you can) in place of the Toshiba LCD and see if the blurry/ghosting is still present.
    Also check the SCART connections/configuration and placement/quality of the leads

    Interesting post on ghost images here
    http://www.digitalspy.co.uk/forums/showthread.php?t=675089
    and these
    http://tinyurl.com/5h6phm
    www.bbc.co.uk/reception/info/pdf/trees_factsheet.pdf
    and although this is American the principle is the same
    http://en.allexperts.com/q/TV-VCR-Stereo-1749/Hitachi-57-picture-ghosting.htm
    Last edited: Jun 25, 2008
  8. Adrian_F

    Adrian_F Active Member

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  9. Steppenwolf

    Steppenwolf Member

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    I just watched BBC2 on Freeview DTV and swapped to Sky while the same politician's face close-up was filling the screen. ON DTV the picture was perfect and on Sky, his face looked pockmarked. I then went to the bedroom & checked the same thing; this is closer to the dish and both DTV & Sky gave similarly good images.

    So it boils down to - I think - loss of signal in the Toshiba due to the long cable length. I just did your CRT test - coincidentally the same one that was married to that old skybox before with a shorter cable run and gave excellent images - and the CRT also had the same problem, although less obvious. Ghosting is more with Euro 2008 and such brodcasts; with BBC and ITV the colours look pasty and unnatural (not improved by playing with the settings; moreover, great on DTV) and the skin tones somewhat unnatural pockmarked.

    I have charted a shorter route to the dish and hope that the new engineer coming in will oblige. It involves no more holes and is more straightforward.

    I have heard that certain better quality Sky cables (like Maplin's XS46, but at £1.59 per metre, that would set me back some £75) cause less signal loss. Is that true? :lease:
    Last edited: Jun 25, 2008
  10. fernandez

    fernandez Member

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    A comparison of cables/cable losses can be found in the Satcure link in post #2.

    It would still be interesting to know what the signal strength/quality readings are on the problem box and perhaps you could compare them to the same readings on your other box(es).
    I know that these readings can vary between receivers and are, at best, only a guide - call it curiosity.
    Meantime the outcome of the Sky installer's visit is eagerly awaited and until then I'll shut up:D
  11. Steppenwolf

    Steppenwolf Member

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    Thanks Fernandez, you have been helpful. I just spoke to Sky installers and they said that they only provided standard cables and the low loss ones were not available even at extra cost. But they agreed to explore the shorter route to the dish and also to try the little in-line booster at the satellite end.

    If worst comes to worst, I can get a Sky qualified engineer privately; I have already spoken to a local one and we have agreed that I'll call him if the Sky engineers visit turns out to be unsatisfactory.
  12. fernandez

    fernandez Member

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    Was this problem ever solved and, if so, how?

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