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SwedishRider
Rider on the Storm
Premium
join:2006-01-11
not Sweden
kudos:1

CATV issue- box freezing and reboots.

I'm hoping the mods let this fly, as I'm not getting any responses in the appropriate non-direct support cable forum, and I think some in here might be able to offer some help (and this is a "home improvement" if I can get it straightened out ).

I'm having a weird, nagging problem with my CATV (Charter), and I, along with their Charter Direct team and local techs are trying to figure this out... below are cut from the other forum, but include the relevant info... any ideas? Thanks in advance!

Just to give you my setup (which was installed by Charter), the main drop off the pole is RG-11 in underground conduit to the Charter box on my house, then coupled to RG-6 and runs into my home's utility room. It is then split by an Antronix splitter (CMC3003V) with the -3.5db leg servicing the CATV. Signal leaves the splitter and enters an 8-output amp (Extreme Broadband IPA1008D-RSVF, supplied by Charter) and then leaves via RG-6 to service the various television outlets and cable boxes in my home, each outlet having its own home run back to the amp in the utility room. Cable is high quality, shielded properly and adequately, and has the high quality quad shielded coax fittings that have been looked over by Charter techs in the past. I currently have 3 cable boxes: a Scientific Atlanta Explorer 8300HDC, a CISCO Explorer 8640HDC, and a Scientific Atlanta Explorer 3200.

Here's the issue(s):
Most of the time, all three cable boxes seem to work well, but something happened today that somehow demonstrates an intermittent problem that all three have (but the 3200 seems to be most problematic).

I was trying to access Sprout programming through On-Demand on the 3200, but the Sprout programming would not load. It searched and searched, but no program. While that was happening, I went to both the other cable boxes in the house, and both were able to access the same On-Demand Sprout programming that the 3200 could not. Then, the 3200 spontaneously rebooted, and after it reset itself, I tried again to access On-Demand, and I could not.

I then unplugged the 3200, and switched it with a functioning DVR, trying to see if the outlet was the issue. Both boxes rebooted, and the 3200 refused to get On-Demand from the new outlet, and the DVR was good to go, immediately getting the programming and streaming it to the DVR. I accessed the diagnostics screen in both the SA DVR and 3200, and both showed SNR strength of 35 db, and no errors. I rebooted both again, and still no On-Demand on the 3200. Finally, the 3200 lost all channels. I could see the programming bar telling the program that should have been playing, but no TV whatsoever. Both DVRs were working fine at that moment... HSI was up and running normally... and Tel had dial tone.

I called Charter Tech support, and a helpful young lady asked a few questions and then sent a "hit" to the 3200, and magically, the box's TV programming reappeared, and On-Demand worked as normal.

My question: why is this happening? I've had techs here in the past and my signal strength and clarity has consistently been solid. This was a case where somehow one box went renegade while the others were working fine.

And I would write this off as a lone defective box, except to say that the other boxes act up occassionally as well. The SA and CISCO DVRs tend to have the screen "freeze" in place, requiring me to use the remote to change the channel up, and then back, and things are back to normal. This tends to happen on Sprout in the afternoon (1pm - 3pm typically). It's not an isolated event.. it happens once a day or every other day. The funny thing is.. I have tuned both DVRs to Sprout in the past around that time.. and one will freeze and the other will be normal as if nothing is wrong- and there is no consistent box that does it always.. sometimes it's one, and sometimes it's the other, and sometimes it's neither.

Bottom line: HSI running fine, Telephone running fine, and signal quality from the diagnostic screens on all boxes is good (even during and after an event), as has been the measurements of the techs. This seems to be a cable box issue. Why do these boxes do these random reboots/freezes, and one signal reset by a Charter tech can clear a box that unplugging and plugging cannot fix? Any thoughts? Is this just the typical service from these boxes that I need to expect going forward? Is this a video compression issue or maybe crummy box quality? Please let me know. Thanks!

And then I posted this follow-up:

Well, I'll throw this out there and see if anyone has some ideas..

I just had a tech visit my home, and he thought the problem was probably one of two things: either my 8-port amp (which was an older model and known for problems), or the amp on the pole that services my street. He swapped out the Extreme Broadband amp with the latest generation, and then used his meter to see what kind of signal measurements he was getting at the amp. Measurements at the amp were dead on the money with SNR of 34-36 and perfect signal strength on all frequencies. So pole drop, grounding block, splitter, and amp checked out fine

Coax in the house is a star formation with all home runs back to the utility room. Coax from amp to each outlet is Belden 1829A with high-quality compression fittings on all the runs. Some outlets have runs as short as 5' from amp to outlet, and some are longer, but all exhibit the same behavior (video and audio freezes requiring the channel to be changed to restore video and sound). Meter was used to test outlets, and signal strength and SNR were dead on the money for all outlets- showing SNR of 34-36, signal strength on the money, and no errors whatsoever. So coax runs to all outlets checked out fine

RG-6 with compressions fittings is then used from the outlet to the cable boxes. And the cable boxes report on their diagnostics screens no errors, SNR of 34-36, and signal levels in the sweet spot of tolerances.

With the amp switched out, I thought we had it at first, but last night a random freeze-up happened to one DVR, and this morning, a random reboot happened to the other DVR. So no luck... problem still exists.

Neighbor says he rarely sees a freeze-up, maybe once a month, and that freeze-up requires a reboot, it's not correctable by the remote. Since our symptoms are different, I would think that rules out the street amp, but truck will be rolled to take a look early next week.

Only 2 other possibilities I can think of if street amp checks out as good:

1) Flaky tap. My neighbor and I are on the same amp, but different taps. I would think this isn't the case since it's so infrequent and random, and I'm getting uptimes on my cable modem of 20-40+ days usually.

2) Charter's boxes are just problematic. I had a DVR when I first got Charter that was horrific, and had it swapped out, and this replacement is just annoying. That makes me suspect that these Scientific Atlanta/CISCO boxes are just not up to the compression that Charter's downstream video is sent at. When it gets overwhelmed... it hiccups, and a freeze-up or reboot occurs. That's my theory anyway.

Any ideas or things I haven't thought of? This is really baffling.

Any thoughts?


beachintech
There's sand in my tool bag
Premium
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Does your amp allow return to pass through? If you hook one TV up to the modem outlet (bypassing the amp) do you get the problem?
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


djrobx
Premium
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Valencia, CA
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Reviews:
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·VOIPO
reply to SwedishRider
Simplify to troubleshoot. Try connecting directly to a cable box without the amp, and use an appropriate splitter. Temporarily leave some boxes disconnected if your signal strength is too low without the amp. You can rule the amp out as being the culprit this way.

Keep an eye on your signal strengths, both upstream and downstream. Look for changes after you experience a problem. In other words, perhaps you normally see +3db signal strength, and then following a freeze-up, see -3db. A sudden 6db shift can cause a tuner to get confused, even if it's still within spec. I had this problem - it took the cable company forever to track it down to a bad wire in the node. It was hard to get them to accept there was a problem in the first place, because the numbers were always within spec before and after an event. It wasn't until I looked at the signal strengths over time that I was able to identify the issue. You'd think you'd see these issues on your modem as well, but it may be more tolerant of line issues.

Also make a note of the time, and outside temperature when freeze-ups happen. In my case events would happen in the morning and evening when it got to a certain temperature outside.
--
AT&T U-Hearse - RIP Unlimited Internet 1995-2011
Rethink Billable.


SwedishRider
Rider on the Storm
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reply to beachintech
said by beachintech:

Does your amp allow return to pass through? If you hook one TV up to the modem outlet (bypassing the amp) do you get the problem?

Yes, amps have been supplied by Charter, so they're high quality (I would hope) and allow for return pass.

I have not experimented with bypassing the amp. I think that will be my next step. But no amp has mad the difference yet and my neighbor has the same amp and does not have my issues... so I am suspecting that the root of this problem is not the amp...


SwedishRider
Rider on the Storm
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reply to djrobx
said by djrobx:

Simplify to troubleshoot. Try connecting directly to a cable box without the amp, and use an appropriate splitter. Temporarily leave some boxes disconnected if your signal strength is too low without the amp. You can rule the amp out as being the culprit this way.

Keep an eye on your signal strengths, both upstream and downstream. Look for changes after you experience a problem. In other words, perhaps you normally see +3db signal strength, and then following a freeze-up, see -3db. A sudden 6db shift can cause a tuner to get confused, even if it's still within spec. I had this problem - it took the cable company forever to track it down to a bad wire in the node. It was hard to get them to accept there was a problem in the first place, because the numbers were always within spec before and after an event. It wasn't until I looked at the signal strengths over time that I was able to identify the issue. You'd think you'd see these issues on your modem as well, but it may be more tolerant of line issues.

Also make a note of the time, and outside temperature when freeze-ups happen. In my case events would happen in the morning and evening when it got to a certain temperature outside.

What is a "bad wire in the node"? I have a rudimentary understanding, but that is on the headend I believe, correct? Wouldn't others on my street be seeing similar problems if that was the case?

Interestingly, problems tend to happen early, early morning, and in the early afternoon... and that's if they happen at all. This is more of a nuisance issue that a full-blown problem. But it's enough of a nuisance to hope it can be tracked down and fixed.


SwedishRider
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reply to SwedishRider
Okay, interesting piece of the puzzle. Sprout just froze this morning on the non-DVR box at about 7:40am. I immediately went to the diagnostics screen while Sprout was frozen to see what it was reporting. Sprout here is 741MHz, but the diagnostics screen was showing a frequency of 5XXMHz... which was not Sprout!! I went to a DVR, fired it up, and went to Sprout. Sprout ws playing fine, and the DVR Box showed 741MHz, 7dBmV, and SNR of 35- while the screen was still frozen on the other box.

Question: why did the frozen box report it was tuned to a frequency other than Sprout?!? As soon as I changed the channel and changed it back, Elmo's world returned and the diagnostics then reported the correct 741MHz. But that is interesting... could some kind of forced channel switch be causing this? Very baffling!


beachintech
There's sand in my tool bag
Premium
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kudos:5
Because DVR's have two tuners, and you were looking at the other.

You have a wiring issue that needs to be corrected. Either a bad fitting, drop, splitter, etc. Can't tell you without being there with a meter.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


SwedishRider
Rider on the Storm
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said by beachintech:

Because DVR's have two tuners, and you were looking at the other.

No, the box that froze was non-DVR. Sprout broadcasts on 741 MHz, but when I checked the diagnostics on that box, it was trying to look at 5XX MHz (don't remember the exact number... should have written it down).

Once I changed the channel on that frozen box and changed it back, diagnostics showed Sprout on 741 MHz with a normal signal.

I'm sure that the frequency was not Sprout's... and that box is not a DVR and only has one tuner.


Pacrat
Old and Cranky
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Cortland, OH
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Reviews:
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reply to SwedishRider
Is the installation yours or the cable company's? It appears to me that if all the equipment is theirs and the installation was made by them, that you have every right, as a paying customer, to demand that they fix the problem! Frustrating as it may be, the answer may lie beyond your control. If it were me, I'd wait until it freezes up again, and leave it alone 'til they come out and see the condition. Many times, an intermittent problem is nearly impossible to diagnose unless the diagnostics take place while the problem is "active" and obvious.
--
Keep your eye on the ball, your shoulder to the wheel, your nose to the grindstone, and your ear to the ground. Now, try to work in that position!!!


SwedishRider
Rider on the Storm
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I have inside wire protection on my bill, but they did not install the wires inside the house (that was done during the house build), they installed the compression fittings on the CATV runs, measured the signals at the outlets (and said the signals are great multiple times), and installed everything from the pole to the amp including coax, grounding block, splitter, and the amp itself.

I'm thinking of doing exactly what you say... wait for a day that I know a truck is going to roll, and then let the box stay frozen until they arrive. At least whatever the box is reporting can be seen firsthand. It doesn't always give this freeze on command though... with my luck, that'll be the day when it doesn't happen.


SwedishRider
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reply to SwedishRider
BIG UPDATE: Charter just left, they rolled a truck today to do diagnostics (on a Sunday no less), and the tech used his meter to test at the house before the ground block (cutting the entire house out of the equation).

Result: serious errors racking up.

He then went on the pole and tested at the tap, cutting the coax drop out of the equation.

Result: serious errors racking up.

He said that was as far as he could go. He said he would call it in, but it appeared something was wrong with the tap, the street amp, both or something else chased back to Charter's end, but his test ruled out the house wiring as the culprit.

I'm glad someone finally found the issue! Now I'm hoping this can get resolved expeditiously!


Pacrat
Old and Cranky
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Cortland, OH
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Reviews:
·Time Warner Cable
reply to SwedishRider
Cable companies are funny... at least Time-Warner is. A few years ago the city was installing new curbing in our neighborhood. In the course of digging the the old stuff out, it was frequent occurence that the backhoe "disturbed" unmapped cables from time to time, causing widespread outages throughout the neighborhood. One day, my cable suddenly went out and I looked out my window and saw where the backhoe was working, about a block away. I walked down to the site and saw the ends of the severed cable trunk, sticking out of the ground about 8 feet apart. I called it in to TWC and they made an appointment for a technician to come to the house. I tried to explain to the idiot that sending a tech to my house would not begin to solve the problem, that the trunk had been severed, and no installation techy was going to be able to fix it. I even gave her the exact location of the break... x feet from the stop sign at the NW corner of "Such&Such" St. and "Whatsit" Dr. She still insisted on scheduling a "service call" at my home for the next day.

I noticed that a service crew was at the break site within a couple of hours to, at least, splice in some new cable. Eventually (weeks later), they replaced the whole trunk run around the neighborhood... they had so many repair splices in the line, there were almost daily outages for some homes. I know my frontage (90') contained no less than three splices in it before they replaced the entire run.
--
Keep your eye on the ball, your shoulder to the wheel, your nose to the grindstone, and your ear to the ground. Now, try to work in that position!!!


Jack_in_VA
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join:2007-11-26
North, VA
kudos:1
Reviews:
·Millenicom
said by Pacrat:

Cable companies are funny... at least Time-Warner is. A few years ago the city was installing new curbing in our neighborhood. In the course of digging the the old stuff out, it was frequent occurence that the backhoe "disturbed" unmapped cables from time to time, causing widespread outages throughout the neighborhood. One day, my cable suddenly went out and I looked out my window and saw where the backhoe was working, about a block away. I walked down to the site and saw the ends of the severed cable trunk, sticking out of the ground about 8 feet apart. I called it in to TWC and they made an appointment for a technician to come to the house. I tried to explain to the idiot that sending a tech to my house would not begin to solve the problem, that the trunk had been severed, and no installation techy was going to be able to fix it. I even gave her the exact location of the break... x feet from the stop sign at the NW corner of "Such&Such" St. and "Whatsit" Dr. She still insisted on scheduling a "service call" at my home for the next day.

I noticed that a service crew was at the break site within a couple of hours to, at least, splice in some new cable. Eventually (weeks later), they replaced the whole trunk run around the neighborhood... they had so many repair splices in the line, there were almost daily outages for some homes. I know my frontage (90') contained no less than three splices in it before they replaced the entire run.

It's not just the cable companies. A couple of years ago I called one of our local tv broadcasters engineering about a sync problem with their OTA audio and video. She didn't know they broadcasted a signal over the air using a transmitter and antenna and thought it was all cable and satellite.


SwedishRider
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1 edit
reply to SwedishRider
Okay, another piece to the puzzle. Work was done on the lines to my home, and two problems were found, one at the headend and one on an amp on a pole down the street. We thought problem was caught and done with ... however...

I came home and rebooted all 3 cable boxes (2 DVRs and 1 regular set-top) and rebooted my MTA and cable modem. Everything started with a clean signal... and I tuned all 3 cable boxes to Sprout (Channel 88) so that all three would be tuned to the same channel, and after some time passed, I'd be assured that problem was fixed. Within an hour or so, ALL THREE boxes froze audio and video at the exact same moment. The last image as they froze stayed on the TV screens of all three boxes, and it was the exact same image on all three. I changed the channel and then went back to Sprout, and Sprout continued fine on all three boxes as I changed the channel and back on each of them.

So I kept it on Sprout on all three boxes, and about an hour later.. ALL THREE boxes froze audio and video at the exact same moment on all the boxes again! Exact same thing as before.

Tech came back out and measured at the drop... everything crystal clear. He came in and measured an outlet hooked to a cable box... crystal clear again...

To make sure all info on the table, there are times I'd be watching Sprout, and another TV is on NBC HD (channel 785), and NBC HD will freeze, but Sprout will be fine.. so all the boxes don't freeze at the same time... but clearly it's happening on the same channel at the same time to all boxes tuned to that particular problematic channel.

Any ideas? This is a stumper.. Charter Techs are thinking this one over and will be back in the mornning for round 3.. any takers??

EDIT: And one other thing.. cable modem and MTA have had rock solid connections all throughout this process... the only time they've been down or shown errors is when the drop has been disconnected for diagnostic purposes.. otherwise internet and phone have been solid.


nunya
LXI 483
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O Fallon, MO
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reply to SwedishRider
Back when I had the TV portion of Charters service, frozen channels with good signal was a common problem. Moxi boxes were the worst. I actually found that there was a "sweet spot" signal-wise: Too much (too hot) signal was just as bad as not enough signal.
I've not seen this issue on Motorola boxes, and have no experience with SA boxes.

An amplifier can add a deceptive variable into the equation. Your STB or CM may report "good" signal levels. But, crap amplified is still crap - just stronger.
You mentioned the channel is in the 741 MHz range, which is probably the higher end of Charters spectrum usage (in the olden days, 741 MHz was channel 115).

How long is the drop to your house? You did mention it's RG11. Is it over 300 feet? RG11 is great when RG6 just wont cut it, but it does have it's limitations as well. It's not really that significant a step above RG6 (contrary to what many people, even CATV techs, believe).

What I'm driving at: even if you have a nice acceptable signal at the tap, send it down 350' of RG11 and the upper frequencies are going to slide off. You'll have around a 10db loss @ 741 MHz over 300' or RG11. If the originating signal is nice enough, you can add an amplifier first thing and boost it back up.
But if the originating signal (and this could even be in the CATV distribution plant) is crap that's just been cranked up - you see the problem.

I would ask the technician *specifically* what the signal levels are at the ground block. Especially in the 700-800 MHz range.
Another "habit" that I am guilty of, as are many cable installers, is keeping the modem off the amp. E.G., splitting the signal to the modem first, and then sending everything through the drop amp. This is because many amplifiers do not play well with modems (yes, I know they *should*).
--
If someone refers to herself / himself as a "guru", they probably aren't.


SwedishRider
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1 edit
said by nunya:

You mentioned the channel is in the 741 MHz range, which is probably the higher end of Charters spectrum usage (in the olden days, 741 MHz was channel 115).

I asked about the frequencies, as every time I checked the diagnostics screen after an issue, the frequencies changed! I thought that was a symptom, but tech said that is normal, it's called digital switching cable (I think..) where the cable box locks onto a different frequency if someone else is using that frequency. Sprout, where I saw these freezes happen yesterday, reported to be on 741, 570, 591, and 753 MHz... all within the same day! But apparently that is normal given the infrastructure. And the freezes happened on both 5XXMHz and 7XXMHz.

How long is the drop to your house? You did mention it's RG11. Is it over 300 feet? RG11 is great when RG6 just wont cut it, but it does have it's limitations as well. It's not really that significant a step above RG6 (contrary to what many people, even CATV techs, believe).

Pole to house is about 110'. I have 2" underground conduit running to the house and I specifically had it at least 12" away from house electrical conduit. I think it's almost 2' away underground actually. RG11 is used here for underground installs, even in conduit apparently.

EDIT: And the drop has already been replaced once in the past... this happened both before the drop change and now after. So coax drop is not the problem.

What I'm driving at: even if you have a nice acceptable signal at the tap, send it down 350' of RG11 and the upper frequencies are going to slide off. You'll have around a 10db loss @ 741 MHz over 300' or RG11. If the originating signal is nice enough, you can add an amplifier first thing and boost it back up.
But if the originating signal (and this could even be in the CATV distribution plant) is crap that's just been cranked up - you see the problem.

I see what you are saying. I recorded power levels as reported by the boxes over the day... here's what I got:

579MHz 3dBmV
591MHz 3dBmV
753MHz 7dBmV

I didn't record the 741 MHz power level.. but I would think it's around where the 753MHz level is. Tech checked power signals at the house immediately before the grounding block yesterday (in a variety of MHz ranges, including 700+), and they tested at appropriate levels, and checked for errors and got none (at least at the moment it was checked). He did say it was a short run for RG11, but didn't see anything that would be causing a problem.

I would ask the technician *specifically* what the signal levels are at the ground block. Especially in the 700-800 MHz range.
Another "habit" that I am guilty of, as are many cable installers, is keeping the modem off the amp. E.G., splitting the signal to the modem first, and then sending everything through the drop amp. This is because many amplifiers do not play well with modems (yes, I know they *should*).

Yeah, my modem and MTA are split immediately before the amp, and they've been flawless as far as I can tell. Tech and I went round and round with theories, but he said he thinks we both were overthinking this one. He said if something is fouled up in the head end... and given that all three boxes locked up simultaneously... a big "tell" if you will), then chasing down house wiring isn't going to help... but it may be needle in a haystack time at the head end.


nunya
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reply to SwedishRider
Being on SDV throws a huge monkeywrench into the scenario.

The only thin I might recommend is using a tap instead of a splitter for the CM.

SDV, IMO, is still very Beta. Yes, it's being implemented - like it or not.
Being that one of your boxes "timed out", and all three boxes shit the bed at the same time, I'm more apt to believe that it's a carrier or return path issue. E.G., the STB can't let the node "know" that you are still watching that program. The channel times out, and all you see is the last image.

The only portion you have control over is the amplifier in your house. Some amps that claim to be "digital ready" only pass the upstream return, they don't actually boost the upstream return signal. As far as return path is concerned it's just a passive device.
Check the specs on your particular amp. Make sure it's truly bi-directional.

It could very well be an LE improperly adjusted or failing between you and the node.
--
If someone refers to herself / himself as a "guru", they probably aren't.


SwedishRider
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said by nunya:

SDV, IMO, is still very Beta. Yes, it's being implemented - like it or not.
Being that one of your boxes "timed out", and all three boxes shit the bed at the same time, I'm more apt to believe that it's a carrier or return path issue. E.G., the STB can't let the node "know" that you are still watching that program. The channel times out, and all you see is the last image.

The STB return is on 19 MHz, and I checked the power levels on all three boxes. They are showing about 34-35 dBmV at each box. Tech thought that was pretty good... maybe a hair low, but he then went in the truck and looked at the noise on the node... and there was nothing that could have interrupted communication... it was pretty clean overall.

I will say that I have had some difficulty in the past with On Demand... when I select a program, it will search and search and come up empty handed... like it's looking for something it can't find. not sure if that is directly related to my issue, but he did think that may be a piece of this issue.

The only portion you have control over is the amplifier in your house. Some amps that claim to be "digital ready" only pass the upstream return, they don't actually boost the upstream return signal. As far as return path is concerned it's just a passive device.
Check the specs on your particular amp. Make sure it's truly bi-directional.

It has 0.0 forward gain, and 0.0 reverse gain, so it simply repeats in and out what it's sent with no loss.

Tech said they set up a sling box in the headend, hoping to catch a freeze event, and then take it from there. he said that ironically, the head end was watching a SDV channel last night, and they shut off the TV but forgot to shut off the cable box. They came in this mornning... box was frozen on a picture with no audio... just like my problem. They investigated and learned that 360 minutes is the timeout... but are not sure how often the STB needs to communicate with the headend to keep the stream going.

And if that is the reason... why is my return not able to communicate with the headend to keep the stream, but a quick channel change instantly fixes the problem?!?


nunya
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You might consider one of these: »www.cabletvamps.com/Products/ERA-4100.htm to use in conjunction with your existing amp.
--
If someone refers to herself / himself as a "guru", they probably aren't.


beachintech
There's sand in my tool bag
Premium
join:2008-01-06
kudos:5
reply to SwedishRider
Ingress that seems to be taking out that QAM possibly. Again, without a meter that's hard to diagnose over the web.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


beachintech
There's sand in my tool bag
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reply to nunya
said by nunya:

You might consider one of these: »www.cabletvamps.com/Products/ERA-4100.htm to use in conjunction with your existing amp.

Do not install this. Reverse amps should only be installed by the MSO, not a homeowner without a meter. They are very rarely needed. From the sounds of it the issue is most likely outside of your house.

Have you tested a single box bypassing the amp yet?
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


SwedishRider
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said by beachintech:

said by nunya:

You might consider one of these: »www.cabletvamps.com/Products/ERA-4100.htm to use in conjunction with your existing amp.

Do not install this. Reverse amps should only be installed by the MSO, not a homeowner without a meter. They are very rarely needed. From the sounds of it the issue is most likely outside of your house.

Have you tested a single box bypassing the amp yet?

I offered to do that for the tech, but he is convinced that it's not the amp nor the house wiring, and declined my offer to do that. He is suspecting it's something in the headend or a return signal issue. They're hoping to catch a freeze-up on the sling box and take it from there.

When he and I checked his laptop displaying the noise on the return frequency, it looked pretty clean (at least that moment). Is my typical return signal strength of 34-35 dBmV high enough to overcome most noise? I know a cable modem can go upwards of 55 if needed to overcome noise... what should I be pushing to get a quality return signal?


SwedishRider
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reply to beachintech
said by beachintech:

Ingress that seems to be taking out that QAM possibly. Again, without a meter that's hard to diagnose over the web.

98% of the time, I can simply tune to a switch digital channel or get On Demand programming with no issues... it's very weird and random when this freezing happens. I had 2 freeze-ups in the last 24 hours and documented the times. I'm hoping the sling box caught them so that a diagnosis can be made.

If it were ingress, wouldn't I be having lots more problems, lots more often... or others be in the same boat as me? Someone watching popular channels at peak times wouldn't notice i suppose.. but someone watching Sprout in the middle of the night might.

But again, if it was noise, why can I simply move the channel and return to refresh the signal, or just tune to a channel and immediately get the feed 98% of the time... shouldn't that be problematic at least a decent amount of the time?!?

Seems to me that the initial request is making it though but the "pinging" of the STB back to the node to keep the feed going is what's not working... but why that and not the initial requests?!?


beachintech
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There are a lot of things that can cause intermittent problems, someone keying up a mic, etc. We had an issue like that here, it took a long time to resolve, but it turned out to be a bad piece of equipment in the field (Amp AGC). This was VOD though, we didnt do SDV when I was there.
--
Ex-Comcast Tech at the Beach. I speak for myself, not my former employer.


cypherstream
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reply to SwedishRider
Did they do a software update recently to the SDV client or set top boxes?

Sounds like when you change the channel the SDV request is made, and delivered. But the software in the box is not generating the heartbeat and it times out eventually. Or it does generate a heartbeat but after 360 minutes the SDV client does not inform the UI to display "If you want to continue watching this channel push A" (or whatever the message is). The timeout value on the SDV gear is configurable and the timeout value on the guide software is also configurable.

Perhaps there was a software update or firmware update to SDV servers that reset the timeout to the default 360 minutes, but the client guide software in the set top boxes are set to something like 600 minutes. Therefore the "press this key to continue watching" prompt never makes it before the SDV session is torn down. The last keyframe seen is what ends up being frozen. Change the channel forward and back and the STB OS sends the request to build the SDV session again.

The session is only torn down if no one else in the node is watching the channel within the timeout value. So it may not happen on a more popular network than say Sprout, which is usually on a certain level of service and not watched as frequently as something more mainstream. This contributes to the lack of reports on the issue and why its taking so long to figure out. Try another channel that is low on the totem pole for your area. Like Ovation or Reelz channel, or maybe Horse Racing TV if you have that. Anything that's not on a 'basic' tier.

Just a thought. There's a lot of pieces at play software and IP networking wise between session resource managers, sdv, oob carousel, DAC (moto) or DNCS (Cisco/SA), and edgeqam's.


SwedishRider
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said by cypherstream:

Did they do a software update recently to the SDV client or set top boxes?

They've done firmware updates on and off, but this has been going on for years to be truthful. I have not been pushing the issue until now since my contract is up and I'm free to shop around, but I've had multiple CISCO/SA boxes swapped in and out... same thing

Sounds like when you change the channel the SDV request is made, and delivered. But the software in the box is not generating the heartbeat and it times out eventually. Or it does generate a heartbeat but after 360 minutes the SDV client does not inform the UI to display "If you want to continue watching this channel push A" (or whatever the message is). The timeout value on the SDV gear is configurable and the timeout value on the guide software is also configurable.

The STB has and does generate the "press this key to continue" message before timing out after hours and hours of use, but the freeze-ups are randomly happening much sooner than 360 minutes. It could be 45 minutes after switching to a channel. It could be 3.5 hours... but most of the time, it's pretty problem free. I think it's more of the "heartbeat" not being sent or not getting through and the node shutting off the stream.

Perhaps there was a software update or firmware update to SDV servers that reset the timeout to the default 360 minutes, but the client guide software in the set top boxes are set to something like 600 minutes. Therefore the "press this key to continue watching" prompt never makes it before the SDV session is torn down. The last keyframe seen is what ends up being frozen. Change the channel forward and back and the STB OS sends the request to build the SDV session again.

The session is only torn down if no one else in the node is watching the channel within the timeout value. So it may not happen on a more popular network than say Sprout, which is usually on a certain level of service and not watched as frequently as something more mainstream. This contributes to the lack of reports on the issue and why its taking so long to figure out. Try another channel that is low on the totem pole for your area. Like Ovation or Reelz channel, or maybe Horse Racing TV if you have that. Anything that's not on a 'basic' tier.

It's not after 360 minutes though... it can be much sooner than that. But I agree it's with less popular channels. Typical freeze-ups I posted of were on Sprout, NBC HD, even the Smooth Jazz music channel has frozen... so I agree those are probably not being watched anywhere else on the node.. but why is the return signal not being generated or getting through to the headend, but a quick channel change will fix the problem?

Just a thought. There's a lot of pieces at play software and IP networking wise between session resource managers, sdv, oob carousel, DAC (moto) or DNCS (Cisco/SA), and edgeqam's.

Yeah, I feel like it's needle in a haystack time. I'm hopeful it can be fixed relatively quickly... but if not, I'll have to decide if I just want to "live with it" or keep internet and phone (which are working flawlessly) and resubscribe to DIRECTV. I'd rather keep my bundle with Charter... but this doesn't seem to be an easy fix, so I don't know how long they'll chase this until they decide it's too random to diagnose. They have really been on this so far, so I'm hopeful they catch it and get it fixed.


SwedishRider
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reply to SwedishRider
Techs came back for another round today, and here was the deal:

Slingbox was clean, so the problem is definitely between me and the node.

Most likely suspect at the moment: low signal strength on the return path, so they eliminated the amp and went with a 8-port splitter, which has a signal loss per port of 11 dB I believe. That resulted in the return signal to jump to about 46dB per box... but....

It also reduced the forward signal strength, and some channnels now report values of -8dBmV to -10dBmV.

For the moment, all TVs work, and this will help to diagnose if the issue truly is weak return signal. I'll have to let some time go by freeze free before I can determine if this is the answer to the freezing problem.

My concern, though, is the forward power signal swings due to the weather. It's cold out there now... things will change in the summer. What are the realistic tolerances of a CATV STB with regards to signal strength and still getting a quality picture? Is the range -10 to 10, or wider than that? Will I have enough room to get some swings and not get audio issues or macroblocking?

Tech said if this fixes the freezing issue, but problems arise on picture quality... then it's time to hook the amp back up and pad each box based on what it needs.

Thoughts?


nunya
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See the link I provided above.


SwedishRider
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reply to SwedishRider
Well, RDC is showing 45-47 dBmV on 19 MHz, so I tuned a box to a channel that I thought would be unpopular in the afternoon (obscure movie on a premium channel) and waited to see what would happen...

After 30-45 minutes... it froze.

I'm going to give it the weekend and see if it happens again... but if return signal strength is ruled out... what is left at this point?


Killa200
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reply to SwedishRider
This is sounding a lot like low band sporadic ingress. If ingress was causing excessive return path noise at the time the heartbeat was being sent from the STB, causing the singal not to make it to the SDV setup at the headend, it would collapse the channel from no response. I'm not sure what the channel timeout is after failing to receive heartbeats, so I'm not sure how bursty the ingress would need to be. I can say though that while there is no choice in it due to how narrow the band is, it sucks to be running return at 19mhz.

Cable modem could sustain a certain amount of bursty ingress, especially since it is more than likely higher in the return band where it is cleaner. Even though data / voice is working, it would be interesting to see the T3 / T4 modem errors to see what the plant is telling us.