# Bug Fixed? L185: NO MORE HD SAT DROPOUTS!



## jsanders (Jan 21, 2004)

It took me some time to notice this one, I had to catch up on my recordings.

Anyway, before L185, watching CBS-HD (mainly) I would get audio dropouts and "Acquiring Signal" dropouts. I watched the recorded "CBS Evening News" tonight (7/5/04), and "60 minutes" from yesterday, and THERE WASN'T ONE DROPOUT! 

This is very impressive!

Unfortunately, this isn't deterministic by looking at two shows in one household.

Anybody else noticed an improvement like this? I know it was a problem for a number of us before....

Now, I've found what appear to be three fixes, and one inconvenient band-aid with L185. Eldon could really get some brownie points if they told us a little more about what they did. Regardless of how successful the releases are, it would tell us that they really are putting a real effort into making the 921 a solid, first class consumer electronics device!


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## tgerrish (Jan 20, 2004)

jsanders said:


> ...Anyway, before L185, watching CBS-HD (mainly) I would get audio dropouts and "Acquiring Signal" dropouts. I watched the recorded "CBS Evening News" tonight (7/5/04), and "60 minutes" from yesterday, and THERE WASN'T ONE DROPOUT! ...


I'm not sure that L185 was the fix, but I too have not seen dropouts on CBS-HD like I was seeing previously. I will be watching carefully now that you've brought this up...


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## DonLandis (Dec 17, 2003)

By simply doing my appliance timer reboot, the important keyword of "Reboot", that I began about 10 days before L185 arrived, I too have observed a number of changes for the better. I would not be surprised that rebooting daily has resulted in a refresh of the system for better OTA channel response as well. 

If we may get analytical on this, maybe if Eldon can locate "ALL" the factors that are temporarily corrected in a reboot and fix those, then rebooting may become unnecessary. But right now, it appears that rebooting daily is a way to do A ONE STEP CURE ALL. 

Additionally, I have observed that when Mark first began to recommend rebooting as a way to fix some of these timer issues, he said you need to reboot at least every 10 days. At that time I felt that was way too long. I believe he was saying that because he could observe some issues begin to surface after 10 days that could be quickly eradicated with a reboot. I suppose my, every 24 hours reboot was overkill but for me it was a way to access a simple low tech device to do the reboot automatically every day. Lately, I see Mark is now saying Leave your 921 on to avoid the L185 reboot but you will have problems "after about 4 days" I'm guessing he too has decided that the 10 days originally suggested is too long between reboots. 
I have only one data point and that is me. Since doing the daily reboots, no timer failures, no sluggishness, and no OTA losses. BTW- I wasn't the first to recommend rebooting every 24 hours.


Regarding L185 reboot- Has anyone yet monitored this process? It happens when the 921 is in standby but I don't believe it disconnects the power, otherwise what would turn it back on? Is there a battery in the 921 that they have accessed that still powers a switch on the main power? At least with my timer system, I know my reboot process closely replicates the power plug reboot process that, when all else fails, is what the E* ADV techs have you do to fix stuff before they give you an RMA.


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## pculley (Dec 23, 2003)

DonLandis said:


> Regarding L185 reboot- Has anyone yet monitored this process? It happens when the 921 is in standby but I don't believe it disconnects the power, otherwise what would turn it back on? Is there a battery in the 921 that they have accessed that still powers a switch on the main power? At least with my timer system, I know my reboot process closely replicates the power plug reboot process that, when all else fails, is what the E* ADV techs have you do to fix stuff before they give you an RMA.


I suspect it is like a PC doing a "shutdown/reset"; it asserts the reset signal to the CPU and PCI busses. After all, the motherboard in this thing is basically a modified PC motherboard with x86 CPU, PCI bus etc.

There may be a few items not fully reset by this process like the core microcontroller on the hard drive, but this usually is as good a a full powerdown (better in that it won't mess with the hard drive by losing power during a write to disk).


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## jsanders (Jan 21, 2004)

DonLandis said:


> By simply doing my appliance timer reboot, the important keyword of "Reboot", that I began about 10 days before L185 arrived, I too have observed a number of changes for the better. I would not be surprised that rebooting daily has resulted in a refresh of the system for better OTA channel response as well.


I'm glad it works so well for you with your appliance reboot method. However, I am not rebooting every day, closer to about once a week, and I see the improvement with the Satellite HD channel without dropouts now.

It is rather unlikely that a reboot would add any value towards improvement in this area. Here are a few reasons why....

1. Acquisition/tracking/decoding/error correcting are all algorithmic. These don't steadily degrade over time. Nobody complained before that the situation would get steadily worse over time before.

2. These algorithms are generally going to work on fixed size buffers. Things that cause problems over -time- usually use pointers or handles (pointers to pointers) that use heap structures. Fixed buffers are not nearly as likely to cause memory leakage.

3. Once you get the "acquirng signal" message on the screen, the channel basically did a reset all by itself. At this point, the slate is wiped clean, it started over all on its own. If the channel reset itself every 10 or 15 minutes (which was the case for me), then there would be no need to reboot the machine as the channel rebooted itself. Or, conversely, simply changing channels starts the process over again. I never noticed things getting better after rebooting before L185.

These problems were possibly caused in the MPEG decode, or Forward Error Correction algorithms. At least, that is where I would have started to look. Probably some nasty edge case in there.

There are two possible places this could have been fixed. They could have added more error correction bits transmitted from the satellite, or they could have found an edge case in the software or hardware of the receiver.



DonLandis said:


> Regarding L185 reboot- Has anyone yet monitored this process? It happens when the 921 is in standby but I don't believe it disconnects the power, otherwise what would turn it back on? Is there a battery in the 921 that they have accessed that still powers a switch on the main power? At least with my timer system, I know my reboot process closely replicates the power plug reboot process that, when all else fails, is what the E* ADV techs have you do to fix stuff before they give you an RMA.


Oh, we sure need Guruka for that one, he actually saw spontaneous reboots happen in the past! Haven't seen him post much lately, but I know he is lurking around. I saw his name in the voting results of the loosing OTA stations poll.

I don't know if you really need a battery on the reset or not. I suspect they are just doing some cleanup code, then hitting the reset vector, which wouldn't require any stored power source like a capacitor or something. The way to tell is if you hear a "Click" sound when it reboots. If some solenoid actuates, then there is a physical connection being made, otherwise, the likelyhood is lower.


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## guruka (Dec 27, 2003)

> <snip>... Oh, we sure need Guruka for that one, he actually saw spontaneous reboots happen in the past! Haven't seen him post much lately, but I know he is lurking around. I saw his name in the voting results of the loosing OTA stations poll.


 :lol: I believe the coded reboot in L185 takes place at an early AM hour when receiver is on standby, so no, I haven't seen it. The two spontaneous reboots I saw (way back when) looked just like a power switch reboot. Blue HD output LED goes off - screen goes black - (the 921's DVI output is switched off) - pause. . . and up comes the Limited Edition DishNetwork Memorial HDTV Medallion and the receiver goes through the normal process back to live output and a picture on screen.

.....G


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## tedhny (Jan 23, 2004)

As I've posted before, our 921 is in the bedroom and the noise drives me nuts. So I've been using a power strip to shut down the unit at night, restarting the next day.

I've experience few, if any of the problems reported here - no OTA losses, no reboots, very, very few missed recordings. It mostly works like a real machine.


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## Jim Parker (Aug 12, 2003)

I have been getting a lot of drop outs (several an hour) on the 921 and the 510 the last 2 months or so. It does it on all channels. First to go is the sound, then the picture gets blocks of pixization for 1 to 3 seconds. I have been watching the locals mostly, and with a signal strength of 125, I knew it wasn't a weak signal. I have a 48" dish looking at 110 and a 36" looking at 119, so it is not a bad LNB or a cable. 

Then I had a lot of channels go completely out. I ran a check switch and it showed a problem with the SW44. Moving cables around, it seemed that the problem was the switch. Ah hah! The solution to the drop out! So, I replaced it. Guess what? I still have the drop outs!  

I'm not sure what the problem is. Don't know if it is at my end or not.

Any advice? Anybody else have this problem?


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## jsanders (Jan 21, 2004)

Jim Parker said:


> I have been getting a lot of drop outs (several an hour) on the 921 and the 510 the last 2 months or so. It does it on all channels. First to go is the sound, then the picture gets blocks of pixization for 1 to 3 seconds. I have been watching the locals mostly, and with a signal strength of 125, I knew it wasn't a weak signal. I have a 48" dish looking at 110 and a 36" looking at 119, so it is not a bad LNB or a cable.


Hi Jim,

I take it your problem hasn't cleared up then? I'm sure you removed any snow from your dishes, but in the last two months that probably wasn't much of an issue anyway.

The symtoms sound the same as mine, only it was primarily on the *satellite* CBS-HD that requires some waiver. I would get exactly what you mentioned, several times an hour, and now it has nearly completely dissapeared.

It is interesting that it happens with your 510 too. Here is something to try out, since you have two receivers. Use one receiver to just watch the signal strength meter, and the other to watch a program. When you see the dropout occur, do you see the signal strength on the other unit drop? It might add some sort of a clue to what is happening, or not. Might be worth trying though... Just make sure that you are watching a program that is being transmitted on the satellite signal strength you are watching.


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## DonLandis (Dec 17, 2003)

You should be aware that a larger dish will give you, not only a greater signal gain factor but has the downside of requiring a finer adjustment to achieve that as the focal point cone is much smaller. I little off angle and you could see a rather sharp dip in the signal. Considering you have a peak that is looking like maximum, I'd say your dish alignment may be right on but how stable is your mounting. Does it wobble at all? Does it shift in the wind at all? A little wobble on a large dish with a small LNB throat could be cause for intermittant signal loss that could affect the steadiness of the picture. Finally, is the dish in the clear or are you shooting through some trees? 

Also make sure all your cables are clean and water tight with sealant at the connections. A little corrosion at the connectors or moisture in the cable can also wreak havoc with signal steadiness at the receiver.

The signal meter may have too much lag in it's response time to indicate a problem. I have a 28" dish here for 61.5 and it was a devil of a time to lock that thing down for a steady strong signal. The smaller dishes like the 500 are easy to align.


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## jsanders (Jan 21, 2004)

If there is a lag before the signal strength goes down on the meter, that is okay as long as the lag isn't longer than the period of the dropouts. Ex. If the lag is 10 seconds, and the dropout happens every few minutes, there is no problem. If the lag is 1 minute and the dropout happens every 30 seconds, then you have a problem. Just note the time when the dropout occurs, and the time when any signal strength drops occur. The lag is probably the result of filtering (more critical when dealing with low signal levels than high ones). If you see a drop in signal with the same periodicity as your picture/audio dropouts, then you may have found your problem. If you don't see any signal drops, then something else might be the problem. It's your choice of course as to what you want to do, trying that may not tell you anything, or it may confirm your suspicions.


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## Jim Parker (Aug 12, 2003)

Good idea. I'll look at the signal strength and see what happens when I get a drop out. The mount is solid. I'd expect drop outs, and do see it, when the the wind is blowing more than 20-25 mph. However, it does it when it is dead calm. You're right about the focal point. Moving the edge of the 48" dish 1/2" is enough to drop from 125 to 0. I added a support bar across the back of the 48" and it significantly reduced the drop outs from wind. I am going to do the same to the 36" sometime soon.


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