LNB Question

Discussion in 'Satellite TV, Sky TV & FreeSat' started by spacebiscuit, Jul 22, 2018.

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  1. spacebiscuit

    spacebiscuit
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    Are there any visible signs that an LNB needs replacing? I am trying to setup a motorised receiver with USALS that I have purchased and I can't get a signal. If I check the lnb the flay side that faces the dish is bulging a little - I'm not sure if this suggests replacement is needed?

    I had signal briefly on one transponder at 19e, I nudged the dish left and right and then totally lost the signal. Another dish in the same location receives my skyq sevrice so unlikely to be building or trees in the way. Have also checked the f-connectors.

    Any ideas?
     
  2. davemurgatroyd2

    davemurgatroyd2
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    If by flat face you mean the usually plastic cap facing the dish then that has no bearing on reception as it is transparent to the satellite signal and has no components inside that would cause swelling other than air pressure or heat deformtion.

    In over 30 years the only visible signs I have ever seen of lnb failure are corroded connectors and water/rust marks fron drain holes and connectors.

    Nudging the dish should move the lnb arm by millimetres only and should be immediately reversible if signal lost. Remember that aligning a dish is not only horiontal adjustment but vertical as well - tested by lightly pushing lnb arm up or down - if signal goes up pushing arm up then dish elevation needs lowering slightly and vice versa.

    How are you measuring signal levels? If using a receiver's own metering then remember that the receiver can take a good few seconds to lock onto signal before displaying the level - a great deal of patience required and cannot be rushed.

    If you received a signal once then it is unlikely the lnb is faulty.

    More details please on what you are trying to achieve, dish size and type, lnb make and model, receiver, what satellite(s) you are trying for, your location?. Remember also that initial alignment of a motoried dish should be on your southermost satellite - if in the UK that is 0.8W do not wave dish around the arc yet.

    Aligning your first dish can be a very time consuming and frustrating experience but once you have achieved it a couple of times it gets a lot easier but patience and very small movements with reasonable time for receivers to lock are the key
     
    Last edited: Jul 22, 2018
  3. spacebiscuit

    spacebiscuit
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    The receiver is a Zgemma H2s.

    Previously I had my dish working on USALS with another receiver. I removed the old receiver and added the new, added the longitude and latitude settings and then loosened the dish off and nudged it a little to get a signal on 28.2e.

    I am using the receivers software to meter the signal, and I think you're right, it maybe a little slow to respond and register the signal.

    I am sure I have an inline singal meter somewhere - I will try that perhaps.

    Thanks!
     
  4. spacebiscuit

    spacebiscuit
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    I managed to find a signal on 13e and 19e, however not all transponders have signal. Of the transponders that do work I get very raried readings, eg:

    SNR: 72% / AGC: 98%

    or

    SNR 0% / AGC 0%

    and typically:

    SNG: 72% / AGC 3-4%

    These are completely random, or both H V polarity transponders. This is making me believe that perhaps the lnb needs replacing?

    Any feedback welcome.
     
  5. TJT1

    TJT1
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    Are you sure that the dish is pointing to the right sat? i.e. Do you get the usual UK stuff when you think it is pointing to 28.2E?
     
  6. spacebiscuit

    spacebiscuit
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    Yes I defintely have the right satellites. For example on 4.8e I can ge tonly one transponder with 98% signal and 72% AGC. The test are all 0. On the said transpoder I checked a channel on Lyngsat and was able to view it OTV.

    On 28.2e I get 0 signal, can only get signal on 13e and 19.2e. I have tried a new LNB which gives maginally better signal strength, I am not beginning to suspect the receiver.
     
  7. Vin Blanc

    Vin Blanc
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    Take a look at an article I wrote a few years ago for caravanners who had to re-align their dish at each new location using an "in line signal meter". It may give you a good insight into just how delicate aiming the dish can be!

    Google "The art of aiming a satellite dish"

    Obviously, there are now more modern ways of doing it but it may just help you determine what you might be doing wrong.

    Vin Blanc
     
  8. davemurgatroyd2

    davemurgatroyd2
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    Your differing results on different satellite positions suggests that the mounting pole for your motor is not absolutely vertical
     

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