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Random breakup All Channels in Skokie, Illinois

For the past 4-5 weeks We've been seeing intermittent picture breakup on HD and SD boxes on multiple channels. This random breakup on multiple Boxes on multiple RF paths in same house. This is Not being seen on internet speed bump or Pinplotter Ping change when logged..
Phone is not affected either when the pictures break up either.

Everything will be solid for 3-4 min, then picture will degrade to DCT Blocks for an instant, then it's perfect for 3-4 min more. HD, SD, channel No difference... We've watched SD and HD boxes do this seemingly at the same time. Same thing happens with On Demand playback.

I've checked the tightness of the RF Cabling everywhere. Nothing loose. I've power cycled boxes with no different in symptoms.

Please don't say that it's the TV's, as though HD TV's CAN Create DCT Blocks on their own, Analog SD TV's cannot create DCT Blocks, but the Boxes feeding them can. Both SD and HD Boxes are doing the same thing, and by my wife looking at HD in one room, and Me looking at SD to Analog TV in another room, it appears this is happening on multiple boxes simultaneously... which points to the feed, but it is not evident on Internet nor phone.

We have One HD Box and 3 SD to Channel RF 3/4 boxes. They are all doing this same thing.

I'm thinking there is either a random noise or very fast intermittent signal drop on the cable feed, but would like to be more certain prior to calling Comcast, as I doubt that they'll believe me...

I have shut off AC the rest of the house, and removing AC doesn't change it, nor does disconnecting RF from the individual boxes (and watching on other boxes)...

I'm wanting to measure the RF Feed to the boxes..... I seem to remember that there is a key combination that can be used to display the signal strength on HD boxes, but I've lost my notes as to what it that keystroke combination is.

Is there a simelar menu on the little SD box?

I'd be appreciative of this information if it could be passed along........
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Looking for 1939 Indian Motocycle

P.S. to above post.......

OTA TV reception on HDTV or DVD/BR playback on any TV in house HD or SD DOES NOT Break Up like Cable does....

It's definitely follows the Cable system...
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Looking for 1939 Indian Motocycle

The RF & SNR menus seem to be updating every 3-4 seconds in the menu....

This might not be fast enough to catch the issue.... SNR varies up to 5-6 Db in 3-4 min time
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Looking for 1939 Indian Motocycle

Really only a meter is going to reliably see any spikes or dips/static or whatever, and really only comcast can track down and fix it.
So it's time to call for a tech.

Is it every channel, or just some groups? In the box diagnostics, you can see the frequency you are tuned into. Try tracking that and seeing if it's just one or a group of frequencies with issues.

Personally, I tend to have intermittent issues with Syfy. SNR is good, but every once in awhile, it hashes out for a second or two. I can be fine for a few hours, then have several minutes of constant problems. Some other channels near it in frequency also have occasional problems.

Do any of the houses near you have the same issue?

People on either side of me use Dish...

I did check at work, and SNR varies .3 to .4 Db over a couple minute's time.

At home it varies up to 5Db.
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Looking for 1939 Indian Motocycle

if you cut out some splitters does it go way?

I spoke with a very good phone tech... Megan tonight...

Service call scheduled Saturday. She remotely examined system and it's not flagging any errors. She noted that it's an intermittant. 3-5 min between occurrence. She confirmed that phone was not affected when the issue happened about 5 times during the phone call.

Other than verifying tightness of cables, I'm holding off any major part swapping. The in Line amp in circuit is Comcast's that they installed... couple years ago. They liked that model better than my Motorola bi-directional amp.
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Looking for 1939 Indian Motocycle

They sent a great tech...

Great in that he believed me, as yesterday, when he was here, there were NO Symptoms...
(I took a LG3410a and had it search the cable feed for QAM channels, and was watching on of those in bedroom while wife watched HD in other room, to see if it happened with QAM Channels and BOX channels, but of course now it won't act up.... And then the doorbell rang with the Comcast Tech arriving!!! Just my luck.
I showed him the Single Line I have of the house, and he didn't flinch...

I explained that all boxes did the breakup, seemingly simultaneously, and he didn't flinch.

I showed him that one SD box was prior to the Amp Comcast installed a couple years ago. (One SD box, EMTA, are prior to amp, 2 SD boxes, 1 HD box post amp + 45') and they all breakup, though the Internet and Phone portions are solid.... No problems.

He read the Single Line with me, then looked at HD Box Diags, then took reading at HD Box, noticed Tilt. We checked MFG of splitters, and they were Comcast Supplied, not my splitters. Was considering swapping splitters, but decided to check feeds first.
Took Reading at side of house, noticed Tilt.
Went out to pole, took reading at pole, and determined line from pole to house is culprit.

Replaced RG6 with RG11. Nice! Tilt gone.

during the cleanup he found a cut in RG6 that equated to 25' in the horizonal run in the air from the house.

PROBLEM GONE!

I'm waiting for the email'd Customer Satisfaction Survey... Guy is Good --- Deserves an "Atta Boy"

And now I know how to access SD and HD box Diags, and know 32db SNR is the thing to look for!

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Looking for 1939 Indian Motocycle

The tech replaced rg6 with rg11?

Yep! The length from pole to house was within the rules to use this cable.

That should last quite a while!
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Looking for 1939 Indian Motocycle

Random Breakup is back.... HD & SD Boxes... Another service call ordered...
At least now we know feed to house and to boxes are OK.
I'm going to hook up a QAM tuner up to cable and see if that breaks up,too...
That was the last test I was going to do before, and had inconclusive results...
Found the video promo portion on the On Demand channel. Watched looking at pix Plus the signal strength menu of QAM tuner (LG3410a)... I'm seeing a 4-7 sec signal level change, but no breakup. Back on SD box -4.5 to -4.0 level change at the same time frame that QAM tuner saw, but SN is at 40, and wife seeing no breakup on HD set... so all this is just a base for future comparisons....

Don't you love Intermittents?

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Looking for 1939 Indian Motocycle

Tonight got home to a voicemail from Comcast.....

They downloaded "a new program to boxes"..... Please check the service to see if it's any better.... (Didn't say which boxes)

Checked RF levels.... I'm seeing a chage... Couple Weeks ago 5-6 fluctuation. Yesterday I saw a .5 -- .6 change over time...
It's now varying .1.... I'm seeing this on all boxes..
S/N same as last night...

Looks promising....

Ongoing....

P.S. in past 6 months I've seen an improvement in pix quality of most all HD images...
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Looking for 1939 Indian Motocycle

2 days of solid signal... Cancelled the service call....

Crossing my fingers..... That it was a box firmware upgrade....

Just in case..... Mods please don't lock this thread...
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Looking for 1939 Indian Motocycle

Breakup is still there, just longer term between occurrences....

Hasn't been much wind lately.. Maybe that has something to do with it...

It's definately something external.
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Looking for 1939 Indian Motocycle

so did you set another service call?

Rain in the cables?

No service call yet... I'm trying to determine if it is worse in wind, or rain, and doing one more doublecheck that nothing in house is causing this..
When it happens, the time of the disturbance is 1 or 2 video frames long, some times accompanied by audio disturbance. it's not long term (It's extremely fast duration-- 1 or 2 frames of breakup). I've seen SD or HD Sig Strength dip a bit when the other image breaks up, then instantly recovers.... As mentioned before, If I watch in one room, and wife in another room, we'll both report breakup simultaneously when we can't see the other set....
We've seen it on any channel that SD or HD box can receive, including On Demand and HBO.
Some days it's better than others.
I've hooked a QAM Tuner (LG 3410a) to cable and monitored signal strength on channels, but the two days I did that, by luck those were days when it was very random..... I've been waiting for a 'bad' night so I could confirm that it happens on QAM too... I think then I'd have a smoking gun.

We have OTA antenna on HD set, and that is fine. Other HDMI's: BRay, HD Interface from video editing system, PC Scan converter, all are fine, and swapping Cable HDMI to other HDMI inputs... and Cable issue still remains. Again, Internet is not affected by this, nor is phone system (Triple Play here)

The brand new RG11 cable feed splits to 3: One to SD Receiver, One to EMTA box, One to Comcast Supplied RF Amp for feeds to HD Box and 2 SD boxes in other end of house.
SD box prior to RF Amp and all HD & SD Boxes (after RF Amp) All breakup simultaneously.
All Coax is RG6 Quad Shield.

I can't think of a way this is not an RF AGC issue upstream of the house.
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Looking for 1939 Indian Motocycle

any ways this may not fix the issues but if you have HD then you should get all HD boxes it costs the same

Spent another couple evenings to verify nothing in the house is causing this.

Time between occurrences is 5-7 minutes.... Still Random in nature.

Once I see it demodulating QAM with the LG tuner, I will call for Service again. Unfortunately, they will think it's an inside occurrence and I don't.

The investigation continues...
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Looking for 1939 Indian Motocycle

Last night I fed Cable RF to a QAM Decoder. (LG3410a DVR), and searched for QVC channel, (something I knew wasn't OTA)..

Pix great. OK... Now with the 3410a Signal Strength display up (3/4 of the way to maximum) I just sat and watched...

I Found it! The Signal Strength 'meter' on the LG has a faster rise and fall time than the comcast cable boxes (SD or HD)....

The signal strength is falling rapidly and rising in sync with the blockiness I've seen and posted many times before....

This is a RAPID SIGNAL LOSS and RECOVERY 1-4 frames later.... Which is what I described in the original post...

This is not coming from inside the house.... It is something external to the house.

If there is a Comcast person here, Please IM me, and I'll pass along the phone number....

It's definitely something on the comcast line somewhere, and it does look like a very fast acting AGC...
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Looking for 1939 Indian Motocycle

Doublechecked the QAM turner sig strength results a second time... Identical as last time, and this time verified (Wife watching HD box in other room) that the QAM tuner RF Drop is in sync with the HD and SD breakup.

So, Called Comcast for service call....

Actually I had to call 3 times... First two folks I spoke with asked what symptoms were, and As I explained that line had been replaced already, or that QAM tuner shows RF Drop, the phone disconnected. Third time I called I explained and got someone who stayed on the line listened, and then 'escalated' the issue.

We talked for about 30 min, during which time he examined and reset the boxes remotely....

Once during his exam the pix broke-up as I've seen before (we were back at HD set at the time), but he said he didn't see any signal issue, and that matches the "Weighted" Sig strength measurements I've seen at the boxes... Sig Strength changes slowely at the boxes...

I hope the tech they send has a meter that measures rapid changes, as this might be whats needed.
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Looking for 1939 Indian Motocycle

they might need to send a line tech. I had a problem at a previous residence where they had to send a tech out once a week. They finally brought the area supervisor out to see the problem and about a few days later it was fixed. I guess the person finally got in touch with the right crew to fix the problem. Took a while but it was fixed. Of course 3 months later we moved.

Service Fellow just left...

First I showed him the single line of the Cable wiring, and we visited each end, of each cable, checking connections. All good. Then, we watched the HD box. In 10 minutes the instantaneous breakup occurred, and he saw it.
He then changed a couple connector ends, and documented all signal levels at house. Signal levels are fine.

He replaced one other connector, and we then watched HD again. In 10 min he saw it break up again.

We then discussed the house wiring, and another check of amp circuit, which was fine.

I commented how on Bedroom (Pre-Amp feed) SD box how last week I hooked up a QAM tuner, dialed in a signal, and watched signal strength readings and saw an instantaneous drop there, on QAM tuner (QAM Tuner aparantly has a faster response time for sig strength displays).

He asked to see this... So I moved cable feed to a QAM tuner (LG3410a) and dialed up 80-205, which was a CSPAN channel. I kept hitting the signal strength button to keep it on screen, and within 10 min we saw the signal dump, then instantly come back to good again.

We agreed that the input is intermittent, and the issue as I've described it is in fact happening, as the service tech saw it multiple times on multiple hardware, Comcast and other MFG.

He is reporting this to his supervisor as something that has been seen and documented firsthand..... (including the QAM tuner results)

He did a search on impending work in our area, and apparently a "Plate" is supposed to be replaced nearby.
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Looking for 1939 Indian Motocycle

The signal strength meter on a TV may not be just actual signal strength, but may be more of an SNR analog. Rather than actually dropping signal, it could be a burst of noise or interference. I have a Sony TV that lists both SNR and signal strength.

Good point. Dunno. But It shows there is obviously something going on, and he saw it, and is escalating the issue.
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Looking for 1939 Indian Motocycle

So.... It's still happening..... When Comcast says they are bumping it up to next level, do they contact you with updates, or ??????
Wife said to call... Phone tech says signal strength had changed, Reset it, and reset boxes...
Time will tell...
Intermittent's are a pain.

12 min later it did it again.... So I called again....
and while I was talking to him, it happened a couple other times....

About all I got was a direct line to billing..... I'd rather have a good, solid, signal....

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Looking for 1939 Indian Motocycle

If you have any 4G LTE cellphones in the house especially near tv , power them off and see if it improves your tv issues. They create all sorts of interference and since the transmit and receive is intermittent based on your usage , it may be the source of your problem. Powered on and not in use, they still transmit a "heartbeat" signal.

No any G phones... It's an RF loss issue, that's been confirmed by service folks...
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Looking for 1939 Indian Motocycle