61.5 LNB drift

[Larrykay]

Was reading -7 LNB drift on my 61.5 dish. I replaced the LNB and I'm still showing -7 LNB drift on the 61.5 position. As a last resort I'll cal Dish. Anyone with a sugestion would be helpful.
Thanks

 

[bobl]

Mine was reading an LNB drift of -8 on 129. An installer came out to deliver a 722K to me and when he was here I told him about the LNB drift. I assumed the 129 LNB was bad so he changed it. The LNB drift reading remained so he changed out the dual LNB for 110/119. Once he did that the LNB drift reading disappeared. You might need to change another LNB even though it's indicating the 61.5 location. The installer said he thought it was probably the switch in the 110/119 dual LNB which the 129 LNB plugs into.

 

[magnum2066]

LNB drift = bad LNB. Get it replaced.

 

[Larrykay]

LNB drift = bad LNB. Get it replaced.

Words of wisdom? ( LNB drift = bad LNB. Get it replaced )
Thats what I did got it replaced but problem remained. But I did one other thing after the bad reading came up again, I rebooted the 722 and no more drift is indicated. All is well with LNB's

 

[peaked]

Remember, guys and gals, when you first open signal strength screen it will show results from the last checkswitch. Do another one after changes. Also, you can remove sat. in cable, do a checkswitch and clear results. Once it shows x's where sat. readings should be, hook sat. line back up, checkswitch again. This will give you the true reading.

 

[jlo]

LNB drift is not an issue anymore unless you have legacy rcvrs. Dish Pro rcvrs and Dish Pro Plus rcvrs, basically anything that is not a 4 digit rcvr like 2900 or 4000, has software that searches an unlimited frequency variation for each channel. this is built into their software now, so if you have signal problems check the regular line of sight or alignment

 

[Larrykay]

LNB drift is not an issue anymore unless you have legacy rcvrs. Dish Pro rcvrs and Dish Pro Plus rcvrs, basically anything that is not a 4 digit rcvr like 2900 or 4000, has software that searches an unlimited frequency variation for each channel. this is built into their software now, so if you have signal problems check the regular line of sight or alignment

So your saying if you have say a VIP722 drift will not be an issue but will show up on the info screen? I never realined the dish and my line of sight is good. But after the reboot the -7 drift went away after putting on a new LNB. a little Confused here. Was talking to an installer and he said he has never heard of anything like what you said

 

[whatchel1]

Non issue

So your saying if you have say a VIP722 drift will not be an issue but will show up on the info screen? I never realined the dish and my line of sight is good. But after the reboot the -7 drift went away after putting on a new LNB. a little Confused here. Was talking to an installer and he said he has never heard of anything like what you said

He's saying it's a non issue. That the tuners now can follow the "drift" of the LNB.

 

[navychop]

Mine was reading an LNB drift of -8 on 129. An installer came out to deliver a 722K to me and when he was here I told him about the LNB drift. I assumed the 129 LNB was bad so he changed it. The LNB drift reading remained so he changed out the dual LNB for 110/119. Once he did that the LNB drift reading disappeared. You might need to change another LNB even though it's indicating the 61.5 location. The installer said he thought it was probably the switch in the 110/119 dual LNB which the 129 LNB plugs into.

This sounds more like what happened with me. I had a bad LNB indicator. Guy that came out, with father in tow, replaced both LNBs (500 for 110/119 & another 500 for 61.5, for 2 ViP722 & 1 508), just to be sure. Problem went away.

 

[navychop]

He's saying it's a non issue. That the tuners now can follow the "drift" of the LNB.

Only to a certain degree, apparently.

 

[jlo]

right, it still shows up on the system info screen so we can diagnose the drift if you have legacy receivers as well, since they don't have a super diagnostics screen. our first drift support allowed the receivers to search an 8 point margin of drift, the second let us search a 30 point variation, and now our software lets our dish pro receivers search an unlimited amount of variation. legacy can only search a 6 point difference, because of they don't have enough memory.

 

[jlo]

also im not sure how much we communicate our software and product issues to the techs, but its not unlikely that most techs and customer service reps had not heard about this.... just one of those things

 

[Jim S.]

I had my 622 showing a drift value of 7 and half of the even transponders on 61.5 give me a signal strength of 0. I never bothered to schedule a repair because I don't watch, or for the most part even subscribe to, any of the affected channels, but I'd like to do it sometime in case the problem becomes worse. At some point in the past few weeks it stopped reporting any number at all, just that there was drift, but the transponders still register no signal.

 

[Larrykay]

Great discussion, thanks for all the feed back. I am now educated. But one last question. What is drifting? Is the LNB moving? Is the satilite moving and the LNB cant track it? Or is it an electronics issue. The LNB is warm to the touch and heat kills electronics.

 

[whatchel1]

LNBF drift

Great discussion, thanks for all the feed back. I am now educated. But one last question. What is drifting? Is the LNB moving? Is the satilite moving and the LNB cant track it? Or is it an electronics issue. The LNB is warm to the touch and heat kills electronics.

It's the local oscillator inside the LNB that drifts. The L.O. is what "controls" the frequency of the LNB. That's as deep as I want to get into what makes an LNB work.

 

[ptaav]

LNB Drift.

LNB drift is frequency drift seen at the LNB as a result of temperature variations experienced by the LNB itself. Basically, the LNB tunes to a different frequency than the receiver is expecting.

See Low Noise Block Converters (LNBs) - Stallions Satellite and Antenna
and Frequency drift - Wikipedia, the free encyclopedia@@AMEPARAM@@/wiki/File:Nuvola_apps_ksim.png" class="image"><img alt="Stub icon" src="http://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/Nuvola_apps_ksim.png/30px-Nuvola_apps_ksim.png"@@AMEPARAM@@commons/thumb/8/8d/Nuvola_apps_ksim.png/30px-Nuvola_apps_ksim.png.

Most modern tuning systems rely on a control system known as a phase locked loop to deal with drift. The locked loop can detect a shift from an expected frequency,

Phase-locked loop - Wikipedia, the free encyclopedia

It's important to note that phase locked loops are hardware components designed to compensate for natural noise or variation in another hardware component. I emphasize this because jlo's responses seem to imply an infinitely tunable system. For example, the LNB could be experiencing a drift of let's say -1,000,000 and the receiver could tune accordingly.

I know it's an exaggerated example, but the point still stands. Software can only compensate for bad hardware so much. While successive software updates may improve the receiver's ability to compensate, it will still hit a barrier enforced by the hardware. We can presume that barrier would be indicated by general signal loss, but again, we can only presume.

As for Dish network's stance on it - it's far less clear. While jlo indicates he has access to some base of knowledge that allows him to discount LNB drift as being a problem, Dish network addressed the subject with an internal memo in 2007.

http://mark.koli.ch/2009/01/05/lnb-drift-dish-statement.pdf

Of course, that's two years ago. We must account for the magical software. However, it seems that the System Info Screen presented here may be from a 301 or 311 connected to a DPPTwin. Again, barring that magical omni-capable tuning software, we can say that perhaps Dish Network had business rules covering LNB Drift. From the screenshots presented here, we could construe Dish recommending that DPP Twin LNBs should be replaced if their drift values fall between -5 and -12 or between +5 and +12 in order to prevent future trouble calls.

Draw your own conclusions.

 

[kb2vgp]

LNB drift is not an issue anymore unless you have legacy rcvrs. Dish Pro rcvrs and Dish Pro Plus rcvrs, basically anything that is not a 4 digit rcvr like 2900 or 4000, has software that searches an unlimited frequency variation for each channel. this is built into their software now, so if you have signal problems check the regular line of sight or alignment

If that was true, then why have I arrived on many trouble calls where customers have a SuperDish and the problem is LNB drift? The LNBs on the SuperDishes often drifted creating many problems for customers with Dish Pro and Dish Pro Plus receivers. Once we replaced the SuperDish with a Dish 500, everything was back to normal.

 

[Jhon69]

Mine was reading an LNB drift of -8 on 129. An installer came out to deliver a 722K to me and when he was here I told him about the LNB drift. I assumed the 129 LNB was bad so he changed it. The LNB drift reading remained so he changed out the dual LNB for 110/119. Once he did that the LNB drift reading disappeared. You might need to change another LNB even though it's indicating the 61.5 location. The installer said he thought it was probably the switch in the 110/119 dual LNB which the 129 LNB plugs into.

I had the same issue with 129 showing drift(-8) but I get only 3 SD channels off of 129(which I don't watch that often).So I experimented and disconnected the 129 wing dish from the Dish 500 LNB and reran setup on my 625,now no drift detected.

 

[jlo]

If that was true, then why have I arrived on many trouble calls where customers have a SuperDish and the problem is LNB drift? The LNBs on the SuperDishes often drifted creating many problems for customers with Dish Pro and Dish Pro Plus receivers. Once we replaced the SuperDish with a Dish 500, everything was back to normal.

thats a really good question! ill look into it....... im really not sure, but that lnb does not banstack or bandtranslate, perhaps it has something to do with it, ... thats the only thing i can think of right now...it would make sense if Diseqc doesnt look at each input on the switch for the drift, but thats over my head, and further im probably mistaken

Drift was explained to me as having a channel coming at 2150 MHz but the rcvr finds it at 2140 MHZ, so the drift is -10, for example. That prolly a laymans illustration, ill check out what ptaav said looks a little more in depth

 

[dishcomm]

When LNB drift is indiacted, the LNB should be replaced. The next item is to disconnect the coax from the receiver(s) and run check switch
this clears the matrix.
Once the check switch is complete, reconnect the sat in coax to the receivers and run check switch again.
Check the system info screen details to insure drift message has disappeared