Common Problems- Digital Tiling

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Digital Tiling
Signal Related
Probably the best source of information in resolving digital tiling is the Set Top Box's diagnostics screen. I can only speak to the Motorola and would love an amendment in regards to the SA boxes.
Hard to track digital tiling is usually limited to a handful of channels. Access the boxes diagnostics and determin what frequency the affected channel(s) are on. (Current Channel Status)
Use your SLM ( signal level meter ) to approximate the signal on that frequency. Since most field techs still have an analog meter all measurements will be approximate but still useful enough to track low digital signal.

Measuring a center frequency with a SLM CLI 1450-1750 will yield measurements approx 2.5db off. Add 2.5db to all measurements when measuring in terms of digital freq.
When measuring a digital frequency by channel the reading will be approx 8db low unless the meter is equipped with an accurately configured "DIGICHECK"

Tolerance as follows.
64 QAM channels at the CPE- +5dBmV to -18dBmV
256 QAM channels at the CPE- +5dBmV to -12dBmV
Noise Related
You will be looking for a noise issue if your current channel status or in band status shows an SNR of "POOR" or "FAIR". More information on expected SNR/MER levels can be found here.

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with an sa converter the diagnostic screen page 1 will give you levels for whatever channel you are currently tuned to page 5 gives you an actual s/n level as well as your tuning mode and a return level.

these levels dont seem to be spot on but are close enough that you can see a potential problem.

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The best tool on the SA box is on page 5, the Corr Bytes and Uncor Blks should both be at 0, when signal levels seem OK if these levels are anything except 0 than there is a problem.  Track back until everything is at 0, (ground block), (tap), (amp).  This is on the QAM readings if the FDC (forward data carrier) has some errors, under 200 or 300 and the QAM stays at 0 everthing should be fine.

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Tool whats the easiest way to check on the Moto's? Which pages have the good stuff?

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Tool whats the easiest way to check on the Moto's? Which pages have the good stuff?

In Band Status.
In band status has the SNR for that current channel and the correctable and uncorrectable info.



I was at an escalation today that was a line call, +12/+5 at the tap, -12/-6 at the CPE after the distance and splitters.

The SNR on the box was 27db "poor", no pic at all, correctables and uncorrectables. I replaced the wallfished outlet that was rg6/antennae line hybrid and upped the SNR to 30db "fair" and the picture popped in crystal clear.
Uncorrectables 00000 Correctables 00052.

The Correctables never went above double digits and there were no uncorrectables. My assumption now is that the signal is so low it is affecting the SNR. Hopefully once we get that run balanced the SNR will also raise but until then, the picture is holding steady.

p.s.
The "ingress test" never tagged at -25db. It spiked just below the thresh hold which had my tech thinking there was no noise on the line. Since the test kept saing "pass"
The box told me more and helped more then the freaking meter did!

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I've been getting allot of tileing calls lately, Do to the digital switch Cox is doing...the levels at the tap have been shooting up in the high 30's on the high end...I kinda hate these calls because all I can do is turn it over to systems leaving the customer hanging.

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With this last cold snap our levels in my area jumped as well. Everything is wigging out. Daily I get line calls for +28 or +30 at the tap, +26 on the HSI carrier.
Our line calls went from 30 pending to 120 pending.

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how about that digital tiling on Ba/Ex only, no box..

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My 1st guess would be the drop, and then internal wireing, and then maybe f-conectors or bad splitters....other wise id have to say Id be stumbled on that one......try this one...I have comcast service...and im getting rare random tileing, I have checked everything and it all checks out

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I think I like the SA boxes diag page a little better than the Moto.

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I like the FDC and QAM on the same screen. Makes more sense as it gives a better overall picture of the box activity.

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BAD DCT input signal.. Was actually -28 dBmV on EIA Ch 79 on 550 MHz plant. Have 15 dB of rolloff between Digital pod on Ch 71 and Ch 79 .... OUCH!...This is my bedroom DCT and just started having trouble..I have water to go find tomorrow

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how about that digital tiling on Ba/Ex only, no box..

Sounds like a head end issue, sir.

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The SNR on the box was 27db "poor", no pic at all, correctables and uncorrectables. I replaced the wallfished outlet that was rg6/antennae line hybrid and upped the SNR to 30db "fair" and the picture popped in crystal clear.
Uncorrectables 00000 Correctables 00052.

The Correctables never went above double digits and there were no uncorrectables. My assumption now is that the signal is so low it is affecting the SNR. Hopefully once we get that run balanced the SNR will also raise but until then, the picture is holding steady.

p.s.
The "ingress test" never tagged at -25db. It spiked just below the thresh hold which had my tech thinking there was no noise on the line. Since the test kept saing "pass"
The box told me more and helped more then the freaking meter did!

I would think that may be your issue.  As the Signal to Noise ratio would be what is changing when the signal is lower and thus closer to the noise floor.

I've seen duel tuner DVRs that had 1 faulty tuner in them.  I went out to a repeat call a few weeks ago where the previous tech swore to me that everything was perfect cable-wise since after he'd been there.  It was, but the picture happened to be tiling like crazy when I got there.  When I looked at the inband status, tuner 1 had no erroneous bits while tuner 2 showed thousands of correctable and uncorrectable bits.  Swapped the picture back to tuner 1 and the picture was perfect.  Switched boxes and high fived the customer.  Peace! 

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I have water to go find tomorrow

Funny how we all know that loss of high end is water and low end is loose seizure 95% of the time.

Wanted to add that to get into SA diagnostics you just hold select for 5-7seconds and mail (message) icon will start blinking and then hit info.
To exit you hit the (Wait for it......) exit button.

Note : Seems a lot of these threads are pretty old so if bumping them like this is bad...
  Off ! ! !
hehehe... j/k just shoot me a PM would suffice.
I'm hoping all the techs have an digital meter since last year when the thread was started.
I've often wondered how the cold snaps effect everyone else. We see our fair share of suck-outs and have to roll out at 3AM to start looking for them in the dark and it only gets to low 40's-high 30's here in Fl.