HR24 pixelation - options?

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by su_A_ve, Feb 13, 2019.

  1. slice1900

    slice1900 Well-Known Member

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    One of the major reasons for LNB "failure" is due to frequency drift. Directv LNBs use DROs which aren't as good at maintaining an stable/exact frequency as a PLL (but they cost less...) so the center frequency of a transponder delivered to the receivers might be a little bit off.

    I'm not sure exactly how far off it can get before the receiver has trouble locking on, but it is easy to imagine some receivers are more tolerant of frequency drift than others. It is even possible (though less likely, of course) for this to be the case with two receivers of the same model, or two tuners within the same receiver, since they have their own mixer to downconvert to baseband and it isn't like those are accurate to 1 Hz.
     
  2. studechip

    studechip Godfather

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    I thought you had posted about the differing chips in dvr manufacturers. Regardless, I answered your question already. Or see slice1900's answer above.
     
  3. Superbowl

    Superbowl New Member

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    This is an issue that showed up on Wednesday, February 13. It is constant breakups on NYC locals. It is a problem that appears to be exclusive to HR24-500's only. It has nothing to do with connections or signals levels, etc. This problem is with HR-24-500's and NYC locals. Everyone call DirecTV and let them know about it.
     
  4. P Smith

    P Smith Mr. FixAnything

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    you are too conclusive but have not posted simple data like SS
     
  5. P Smith

    P Smith Mr. FixAnything

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    perhaps I missed a meaning …
    slice did exercise without putting up any real number what pose a risk of accepting his variant
    I've seen LNBF's LOF drift 7-8-10 MHz compensated without breakup of video/audio (BTW, dish diag info screen/msg giving out such drift for dish's LNBFs)
     
  6. slice1900

    slice1900 Well-Known Member

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    It is too bad there isn't a "professional" LNB that uses PLLs for commercial/MDU environments. I'd pay an extra $100 to account for the low demand/production volume of such a thing knowing that it reduced the chance of having problems. I've had to replace two LNBs over the years due to this, so now I keep a spare on hand so I don't have the shipping delay since the third party installer I use is more of a Dish guy and doesn't keep a Directv legacy LNB in stock.

    Of course at $100 maybe I'd be better off putting up a second dish as a backup which would cover pretty much all possible failure modes aside from "tornado blows the dish away" :)
     
    dreadlk likes this.
  7. dreadlk

    dreadlk Hall Of Fame

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    Your whole statement is very true and would normally be the case but Directv certainly took this into account and has the receivers peaking themselves on the slightly off LNB's. I know this because the AIM meter under the Freq correction column shows how far off freq an LNB is on each transponder and some of them are off by quiet a bit (1Mhz+) but the receivers on the system typically all read within the same range, maybe a 2-3 difference in Q.
     
  8. dreadlk

    dreadlk Hall Of Fame

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    I agree. I am shocked that some company has not made very high quality KU,Ka and Rb LNB's that will work with Directv.
    I would also pay a good amount of money for some LNB's that might bring up the signal by 10% or more and delay rain fade.
    I think it is possible as these directv LNB's are so cheaply made that I am sure their is a lot that could be done to make them better.
     
  9. slice1900

    slice1900 Well-Known Member

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    "Peaking" is about aim, it doesn't and can't correct for the LNB having the frequencies slightly off. The AIM meter shows the frequency error so that you can tell how far off the LNB is. I don't know how tolerant the receivers are, but the installers would know and if a customer is complaining about problems and the error is close to the margin they could know the replace it even if there weren't any problems at the same.

    The real problem isn't whatever amount the LNB is off by "out of the box", but changes over time as equipment ages and especially temperature dependent frequency drift. That's where you see LNBs that will pixelate or get 771s when the sun has been on it a few hours, etc.
     
  10. slice1900

    slice1900 Well-Known Member

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    The only way you'll improve signal is with a bigger dish. The LNA in the standard LNB already has less than 1 db of noise, so even a magic LNA that was noiseless would only improve things by about as much as adding 25-30% of area to the dish.
     
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  11. dreadlk

    dreadlk Hall Of Fame

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    A bigger dish is always the best solution but your not going to be able to use the standard LNBs due to the changes needed in spacing them apart.
     
  12. P Smith

    P Smith Mr. FixAnything

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    there is standard way - buy 1.2M AK/HI dish with correct LNBF
     
  13. slice1900

    slice1900 Well-Known Member

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    You just said you would pay more money for a custom LNB that gave you better signal and more resistance to rain fade. What you what isn't a custom LNB to go with a Slimline dish, because what you are hoping for there is against the laws of physics. So you want a custom LNB that's designed to go in a bigger dish.

    Presumably bigger than the 1.2m AK/HI dish, which is a pretty small improvement - theoretically 4 or 5 db and probably less than that in the real world.
     
  14. P Smith

    P Smith Mr. FixAnything

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    if DTV would provide separate Ka LNBF... you could re-use "spoon" C-dish size 10-12 ft
     
  15. slice1900

    slice1900 Well-Known Member

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    Well theoretically you could build this yourself. Use metal/foil to cover 101 & 103 to make a Ka only LNB pointed at 99, the other way around for a Ka only LNB pointed at 103, and use a standard Ku LNB for 101. Then you can locate them wherever you need to get the geometry right in whatever size dish you have - or even use three separate dishes.

    The gotcha is combining everything. For 103 it is no problem, you can connect two outputs from your "103 only" LNB to the 103 inputs on a SWM switch (life is easy now that there's no longer a need for 119) For 99/101 you will need some custom filters to clear out the 950 - 1450 MHz range from the "99 only" LNB and filter out just the 950 - 1450 MHz range from your "101 only" LNB". If you want reverse band you'll need some filtering for that too, but fortunately it can be done with ordinary diplexers (an exercise left to the reader)
     
  16. su_A_ve

    su_A_ve Legend

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    Well, early last week I replaced a few of the crimped connectors with new compression ones, but in the end I was able to swap both receivers with each other.

    Sure enough, the problem was the receiver, as the problem now moved to the other location, ruling out cabling or anything else.

    Called again and finally got a decent rep that set up a receiver swap and even credited me the $20 s/h fee. Hoping to swap it out this weekend.
     
    Rich likes this.
  17. su_A_ve

    su_A_ve Legend

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    So.. the replacement HR24 as soon as I took it out of the shipping box, I could hear some broken pieces. It's all scratched up and can see on the bottom that the front panel tabs are broken. And there is no warranty void sticker. Definitely refurb but the refurb sticker is from 2016.

    They're going to send another one and are assuring me that it will be a new unit... sure..
     
  18. studechip

    studechip Godfather

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    A new HR24? No such thing.
     
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  19. su_A_ve

    su_A_ve Legend

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    That's what offshore said. So after back and forth putting me on hold, I get transferred to the US for no reason. They have no clue, so start from scratch, only to get disconnected. Call again, 3rd rep transfers me to billing, 4th rep transfers me and cannot set up anything because there is a pending return equipment.

    After over an hour he is transferring me to the US who says to go to UPS and have them refuse delivery and return to sender. Once that's complete we can do another replacement.
     
  20. Rich

    Rich DBSTalk Club DBSTalk Club

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    Wonderful. And I thought they were actually doing some refurbishing. I just got a refurb that wasn't refurbed too.

    Rich
     

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