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LNB Drift Detected??


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27 replies to this topic

#21 OFFLINE   P Smith

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Posted 02 May 2007 - 11:29 PM

Oh! That's explain :D.
"drift would best be explained as a point at witch the resonating frequency of the individual intake runners creates turbulence with in the plenum due to inconsistencies in volume/shape or location resulting in an uneven distribution of air mass/volume per cylinder yeilding uneven power ouput per cylinder creating uneven stresses in the reciprocationg assembly leading to vibrations witch over time lead to premature decay in the main bearing/ rod bearing and premature engine failure as the ocilating frequency of the engine changes due to small imperfetions..."
To someone ;) - I'm too old to swallow this 'soup' :P.

Show me how big should be dent for affect 12 GHz signal what will deform one tpn range ( 27 or 36 MHz ) that way when IRD will treat it as shifted median frequency for more then +-5 Mhz. We are talking now about SHIFTING input signal in range 12.2-12.7 Ghz. Ahhh, nevermind.

...Ads Help To Support This SIte...

#22 OFFLINE   ezra

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Posted 03 May 2007 - 12:53 AM

Now shifting is a whole new can of worms but i figured you might get a good laugh at my engine analogy :) I really lost several motors due to freak freq interference issues in my intakes and wife was not happy :( but i survived... now if you would like to play with lnbf drift you can mod your lnbf by removing the cover and changing the symetrical intake of the lnb to distort the wave collected and create turbulace... had this buddy had a call from one guy who had the drift issue and is was actully due to some bees that had gotten inside his lnb and were really messing things up for him... guy had to pay for lnb as insects are not covered under dhpp.. also P smith lets look at some stats here dish has over 13.3 million c\ustomers * varying ages of dishes */varying ages of lnbs and * the weather * manufacturing conditions/quality * a relative chaos element you get some weird results... one of them happens to be the lnb drift phenomenon and i call it the wobble/ woble sp?... it does not happen very often mathematicly (yeah right!) but in the real world where i work and live stuff happens all the time that jsut doesnt follow all those nice logical rules that we like to call physics or maxwells equations hence we have quatum theory/mechanics/ stuff like electrons tunneling when they should not be able too... etc etc so bro dont worry jsut join me one of these and take call "helping" cust all day with these types of issues and then see if all those laws really mean anything in the real world... As my Intergrated circuits profesor said " electrons don't ever play fair in the realworld, remeber they are the biggest cheaters of them all"
so I cheat right bvack at em :)

Now as to the switch issue i believe that has to due with E* engineering desing or lack of that does not terminate unused outputs... when i setup my uplinks I always terminated any unused trucks beacuse they could casue this freak rearfaction (sp?) you know the decompression wave effect taht would dirty up the signal and the modems/ upconverters didnt want/like dirty signals... also I have another theory that may sound totally bogus to you bro but hear/read me out.. eh heh he ..i have tested this at work and it works... usually with lnb drift or intermiten signal loss i have the cust unplug the lnb cable(sat in cable on the receiver) and if there are no other receivers connected i have them touch the copper wire inside the coax with their thumb/ key to the metal head... why do this to reset the lnb and short out/ discharge any capacitance that may have accumulated on the cable over time and the lnb... now how can the cable rated at 75 Ohms build capacitance if it is grounded... well my money is on it not being properly grounded and have you ever ohmed out a grounding block on mine i got 80k ohms yeah that doesn't cut it for me because im sure you know r-c circuits and that there is what i believe truly causes most of the customers no signal/ signal loss issues... go ahead and hook up an ammeter inline with your sat coax and observe the amperage traveling over that cable and if you have a dvr you know that thing runs none stop for ever and ever so in equation world all the currents equal to 0 if we do our circuit analysis but in the real world electrons cheat all the time so we get leaks and sometimes due to wind friction we get static build up on the dish (lord forbid they cheat there too) and well in theory all these electrons would play nice but they cheat so we get hired and have jobs as techs to help people tshoot their problems... now both you (P Smith) and i know that the carrier wave is the most important as the data has been modulated into it and we need to extract it by locking on to it and demodulating out data out of it... if the lnb is drifting it means ( now seriously in my tech opinion) that the wave coming into the lnb wave guide is dirty and the lnb can not clean up the wave to the point where the carrier can have its data extracted within the error correcting capacities of the dbs sytem (my army setup used 3/4 foward error correction) E* i dont know... now 2: the lnb circuits have begun to degrade and noise with in the lnb circuit is actually adding to the difficulty of locking onto the carrier resulting in poor data extraction(intermiten signal loss). 3 an external element has caused disruption/damage to the lnb circuit adding noise to the circuit and leading to lnb failure. Now i dont know if you have ever taken an lnb apart i dismembered a twin dp pro just to look at the wave guide paths and how the circuit looked... now these circuits are by nature/design supposed to be extremely sensitive to rf signals and this sensitivity is what makes them fragile to external variables from their own system (grounding block, switches, dpp seperators (hate these things), diplexers (hate these too)) now all these components have a grouding screw if you look at them and its beacuse every single one of these components can have an adverse effect on your reciver/ switch/ lnb/ signal.... Hew! im tirred and i have to go to work tomorrow again Doh! hope this helps clear up how the drift phenomenon comes about and yes this is my personal theory and i am willing to bet $25 taht if we hook up a spectrum analyzer to one of these drift lnbs-receiver-systems in action or should i say nonaction Im right... he he he and no Im not done yet but this is where i got to stop for now... good night guys.. I put up with enough at work i dont want to see what i deal with at work here. I like to enjoy my time at this forum and help my fellow intellegent man/ er woman too. thanks guys...
Dont Let that TSR fool YOU! Teach them a lesson! Follow along with your tsr at Dishnetwork.com - Cutomer Service - Tech portal and assist your tsr in helping you fix what went wrong! For all you know you might even be able to fix it yourself!:eek2:

#23 OFFLINE   P Smith

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Posted 03 May 2007 - 12:59 AM

Call me next time when you will slip umm drift :) into the issue - I'll bring my SA.

Oh, forgot to tell you - follow yellow brick road :) - um, that URL in post#9 :D

#24 OFFLINE   James Long

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Posted 03 May 2007 - 07:53 AM

It seems that even after Ron's warning this thread is drifting.

Keep the posts related to the ViP-622 DVR please.
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#25 OFFLINE   jgurley

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Posted 03 May 2007 - 03:35 PM

The Tech just left and I still have the LNB Drift message. In order: he ran check switch, did a hard reboot, replaced the LNB, checked and made slight aim adjustment to the dish. I should mention that he had never encountered this "problem" before.

During the week I checked the Drift Message at least a couple of times each day, and it reported in the range of -6.45 to -8.60, most were about -7.50. This morning it was -6.45 (the lowest it's been all week) and that's what it was just before and after the LNB was changed.

The only thing left to do is the replace the dish and tech support wasn't willing to do that at this time (yes, I had them on the phone), especially since the current reading is within the tolerance range.

My thinking is they did all that could reasonably be done at this time. I'll keep a watch on this drift message issue and see what happens. If it does go up consistently then I'll be calling tech support. Until then all else seems well, but I'd appreciate any advice.

This has been quite an interesting thread.
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#26 OFFLINE   P Smith

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Posted 03 May 2007 - 04:14 PM

I would try last approach in SW - clean NRAM. Be aware ALL your settings will gone after that.

#27 OFFLINE   4bama

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Posted 07 May 2007 - 05:20 PM

More data on LNB drift:

We have a 622 and a 508 DVR. My wife is the primary 508 user. A little over a week ago she complained that randomly the 508 displayed the blue screen saying the "signal has been lost, switch to another channel". (Not satellite signal lost, but channel)

I did a detailed channel survey of the 508 and discovered 25 different channels randomly lost, then locked the signal. All were even transponders on 110 and 119 satellites.

I have had no problems with my 622 but from reading this thread I noticed the 622 can detect LNB drift, so I ran the system info on my 622 and it showed both the 110/119 with LNB drift on even-only transponders. I tracked the values for 3 days and noticed the drift values varied from about -5.5 to -7.2, depending on the outside temperature. Late at night or early morning the drift values were lower, during the early afternoon as temps climbed into the 80's the drift vaules increased toward -7.0.

I called Dish and they sent their tech here to check the 508 problem. I showed him what I'd found using the 622 diagnostics and other info I had from here. He replaced the 110 & 119 LNB's, ran a check switch on the 622 then system info again and everything was good...no more LNB drift error message.

The 508 is now solid again with no random channel signal losses.

Obviously the 622 has a more tolerent tuner, or compensates for LNB drift, while the 508 does not. Even when the drift was -7+ the 622 locked to all channels. BTW, switching channels now on the 622 seems faster.

So even if your 622 has no problems, if your LNB drift indicates +/- 6 or more you may get faster channel changes by replacing the drifting LNB(s).

#28 OFFLINE   jarvantgroup

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Posted 07 May 2007 - 11:10 PM

I am glad you confirmed that one problem could be a deformed dish. I am still confused as to why a check switch being performed would correct the problem.


Supposedly LNB drift is to be corrected by replacing the LNB. I've done that and ended up with the same messages. Went on to use some of the 'bad' LNB's, with no subsequent issues....go figure. I really don't pay much attention to the drift issues anymore. At least until Dish can confirm that simply replacing the LNB will cure potential problems. :icon_cool




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