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Discussion Starter · #1 ·
I'm looking for some advice on a problem I'm having with my cable TV.


I subscribe to Time Warner's basic cable service and roadrunner. I have a simple setup. Cable enters my home and passes through a single two-way splitter; one feed goes to the cable modem, and one feed goes to my Samsung plasma TV.


Roadrunner works great. According to Time Warner's online speed test, I have a fast connection. However, on all of the clear QAM channels that I receive, I am having problems with pixelation and with the sound cutting in and out. Sometimes these problems are annoying but relatively minor, and other times the channels are unwatchable.


I had a Time Warner technician visit my house on Friday in an attempt to correct the problem. He tested the signal at the box mounted on the side of my house, at the point where the cable enters my house, at the cable modem, and at the TV. He said all were good. He also told me that the HD channels I receive (i.e., the clear QAM channels) are not from Time Warner, but from the cable lines acting as an antenna and that there is nothing he could do about it. Based on that bit of advice, I'm not sure how much faith I should put into his assessment of the incoming signal strength.


Anyway, after doing some reading on these forums I tried the "hang by a thread" to see if my signal was too strong. That test did not help.


My TV has an option in the channel menu to test the signal of digital channels, and according to that all of the clear QAM channels are at about half (or slightly more) strength.


My question is, does this sound like a problem with the signal itself? Or does it sound like a problem with signal strength?


In other words, is an amplifier likely to fix the pixelation/sound problem?
 

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Quote:
Originally Posted by Mike76 /forum/post/19556525


...He also told me that the HD channels I receive (i.e., the clear QAM channels) are not from Time Warner, but from the cable lines acting as an antenna and that there is nothing he could do about it...

I don't know if an amp would help or not. But I do know the cable guy was full of stupidity & BS.
 

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How do you know that the digital signals you are tuning are QAM? I don't recall having seen any TV set-up menu that displayed that term. I know that with some LG TVs, they are capable of integrating analog FCC channel plan channels, analog broadcast channels, cable QAM channels and broadcast 8VSB channels into one lineup and give the user access to any and all of them without going into the menu. A lot of other brand TVs can decode off-air VHF (channels 2-13) 8VSB digital signals when they are set in cable TV only mode.


What city are you in? If you tell us, we can see what your real and virtual broadcast channel assignments are. In my market, for example, our old analog channel WRC-4 is now broadcast on digital UHF channel 48, but if we directly enter either actual WRC channel 48.1 or virtual 4.1 into a TV tuner that can tune broadcast 8VSB using the remote keypad, the TV displays the exact same program as 4.1. If you can access these local HDTV channels both by entering their actual and virtual channel numbers, then what you are watching is indeed off-air or broadcast ingress.
 

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All cable providers supply the local digital channels in clearQAM IAW with FCC must carry regulations as part of the basic cable service.

With TVs capable of receiving clearQAM the the TV menus you would be selecting digital and cable for clearQAM as opposed to digital and antenna for OTA digital.

Pixelation is caused by the TV not recieiving all of the signals from the cable provider so updates to a currently displayed are not being applied to the correct screen output buffer. The problem is more prevelent with high motion contentl. I suggest bypassing the splitter or turning off the cable modem to be sure that the cable modem actiivity is not causing the problem.
 

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Discussion Starter · #5 ·
Thanks very much for the replies.


Yeah, it was pretty obvious that the technician wasn't well trained. Not that I know very much... He was a really nice guy though.


Anyway, I live near Sandy Creek, NY, almost right between Syracuse and Watertown. According to Time Warner, I am supposed to receive channels 2-14. In addition to those I am receiving 3-1, 3-3, 7-1, 16-1, 16-2, 16-3, 28-1, 50-1, 50-2, and 86-1. Those are the 4 networks plus PBS, a weather station, and WGN. All are duplicates of what I am receiving in channels 2-14, but in HD.


On my TV menu, I go to Channel -> Auto Program, and then select between Air, Cable, and Air + Cable. If I select Air, I get nothing. Cable and Air + Cable give me the same thing. I've been reading whatever I can find online, and I was just assuming that those were clear QAM channels based on that reading. I certainly could be wrong.


Just for clarification, I do not own an antenna.


Thanks again for the help!
 

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Quote:
Originally Posted by Mike76 /forum/post/19556525


........I had a Time Warner technician visit my house on Friday in an attempt to correct the problem. ...... He also told me that the HD channels I receive (i.e., the clear QAM channels) are not from Time Warner, but from the cable lines acting as an antenna and that there is nothing he could do about it......

You should have asked him, "Would YOU like to report your system's problem to the FCC, or should I?"


If their lines were leaking that much, they'd be in violation of the laws on signal ingress and egress.

Also, any locals would not decode as QAM, but as ATSC channels, and on the OTA RF channels. He should have looked at the RF channel numbers, if he really DID think it was ingress.


More likely, something is affecting the QAM signals to the TV....if your internet service is working well, it probably is not due to a bad line, or it would affect those signals as well. It could be that your cable modem is putting out a strong enough "upstream" signal that it is interfering with TV. Try disconnecting the modem, and see if the TV works OK. It could be that the upstream (return) signal is saturating the splitter...is it your own, or a Cable company-provided splitter? If TV is OK with the modem disconnected, you might ask them to give you a good splitter, and also a High-Pass Filter to go on the line that feeds the TV set (if the return signal is overloading the TV). Both are cheap fixes that would cost them little, compared to sending a guy out again.
 

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Quote:
Originally Posted by Mike76 /forum/post/19556983


If I select Air, I get nothing. Cable and Air + Cable give me the same thing.

If your cable line were acting like an antenna and picking up those channels over the air, you would see them on the "Air" and "Cable and Air" settings, but not on the "Cable" setting. So you're definitely seeing the "clear QAM" channels that TWC is carrying. Your cable guy needs to be instructed in this somewhat arcane topic.
 

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Channels 2-14 are analog channels. The other channels are digital channels as indicated by the -1 suffix in the numbers and I fully beleive they are the clearQAM channels that you should be receiving.

Pixelation is caused by your TV not receivng all of the updates to the compressed digital signals,

Try bypassing or turning off the cable modem.
 

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Discussion Starter · #9 ·
The splitter is one provided by Time Warner. While the tech was here, he replaced the old splitter (also provided by Time Warner, approx 5 years ago) with a new one. That did not appear to have any effect.


I just disconnected the splitter and connected the coax from the TV to the coax coming into the house with a male-to-male connector that I had. I didn't notice any improvement - the digital channels appear to have the same amount of pixelation.
 

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Quote:
Originally Posted by jtbell /forum/post/19557087


. . . . . Your cable guy needs to be instructed in this somewhat arcane topic.

The cable guy was probably just repeating the standard company "line" ...... "You can't get HD without OUR box".


He obviously HAS been instructed. Yeah, right.
 

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Quote:
Originally Posted by kenglish /forum/post/19556989


...If their lines were leaking that much, they'd be in violation of the laws on signal ingress and egress....

But it wouldn't be the lines leaking. I've seen ingress coming in through push-on "F" connectors on the back of the TVs that was strong enough to overwhelm the desired signals and strong enough to be reliably decoded in metropolitan reception locations.
 

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Quote:
Originally Posted by Mike76 /forum/post/19556525


My TV has an option in the channel menu to test the signal of digital channels, and according to that all of the clear QAM channels are at about half (or slightly more) strength.


My question is, does this sound like a problem with the signal itself? Or does it sound like a problem with signal strength?


In other words, is an amplifier likely to fix the pixelation/sound problem?

I'm going to go out on a limb here and GUESS ...


Subscribing to standard cable only suggests to me that there may be a filter set to knock down frequencies outside the range used for your analog and the modem. Although walford says "All cable providers supply the local digital channels in clearQAM IAW with FCC must carry regulations as part of the basic cable service.", I've read the regulations and ***I INTERPRET IT TO SAY*** that all they have to supply is the SD version.


I believe it is a signal strength issue, but an amplifier will amplify the noise.


What I would try was suggested by walford as well ... note the signal strength you see. Temporarily disconnect the cable into the splitter (yeah, internet will go down for you) and connect that cable directly to your TV. See if it is better, visually and by signal strength. I'm going to guess it will be a LITTLE better. I suspect that the technician measured the channels in basic, 2-14 or whatever, and pronounced you good. If it is good enough to watch directly connected, I'd look at an amplifier that will amplify cable channels 80-90 (I looked on silicondust and see that is the range for TW in Hastings for the clear QAM). You want to look for a ultra-low-noise amp. You won't need much gain; 10 dB will be more than enough. It needs to be able to handle the strong signals in the analog range without overloading. It will have to go on the splitter output as the cable modem needs upstream and downstream paths.


I doubt that you will persuade TW to remove the (low pass, probalby) filter and replace it with one to notch out the expanded signals.


Good luck!
 

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Prior to the cutover the broacasters were provideing both a SD analog channel and a test version of their HD digital channel on another frequency and the cable comanies only had to provide one of the two so the opted for the SD version.

The cable to your home and the ones at your wall outlets contain all of the cable channels; the SD encrypted and unencypted analog, the unencrypted SD and HD QAM channles, and the unencrypted and SD and HD channles. It is the tuners in your TV or in the cable companies Set Top Boxes(STBs) that determine what you can watch.

I believe some of the signal "strength" indicators actually display the signal to noise ratio and not the strength itself.
 

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Discussion Starter · #14 ·
Thanks again for all of the replies!


I had to work late yesterday, and I wasn't able to bypass the splitter again to check the signal strength. Hopefully tonight.


I did a bit of searching online this morning, and I'm not having much luck finding such an amp. Could anyone point me to a couple of retailers that may carry an amp like that?


Thanks!
 

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Quote:
Originally Posted by walford /forum/post/19561926


The cable to your home and the ones at your wall outlets contain all of the cable channels; the SD encrypted and unencrypted analog, the unencrypted SD and HD QAM channels, and the unencrypted and SD and HD channels.

That may be true in Orange County, but here, if I subscribe to internet only, there is a bandpass filter which makes a TV show "nothing" on the analog channels. The clear QAM came through on the installation like this which my son had.


If one has internet and basic cable, there is a different filter knocking the expanded basic analog channels down to a very low level. I don't know if the clear QAM channels are present at normal levels having never been to their customer with this configuration with a suitable TV receiver. I *SUSPECT* they are.


You are correct ...
Quote:
Originally Posted by walford /forum/post/19561926


The cable to your home and the ones at your wall outlets contain all of the cable channels;

but *courtesy* of filters, not necessarily at levels suitable to even know they are there.


Just to explain what is here in upstate SC via Charter ...


2-(I think)16, analog basic; clear QAM HD status is unknown


17-21 are not apparently used; my sets show "no signal"


add 22-99 analog (with holes) for expanded basic; clear QAM of broadcast HD, of MusicChoice, of CSPAN2, Univision, Inspirational, and some preview channels is here too.


expanded basic, I think, includes a box if desired; that box gives a large number of encrypted SD QAM beyond what I get without the box.


If it wasn't for my wife's love of HGTV, I'd drop expanded and see ... but that would result in a divorce, I fear .
 

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Since cableTV, phone, and internet sevice use 3 different frequency bands the cable company can install a filter to your service to select which of these 3 services you receive. They do not have filters to block some TV frequencies and not others.

Often a cable company will not do a truck roll to disable basic cable when you drop your TV subscription.

With cable TV not filtered out you will only receive the unencrypted analog channels (2-31) and the unecrypted digital(clear QAM) channels. Unless you subscibe to the encrypted channel(ore set of encryted channels) you want and you have a tuner that will decrypted them.
 

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Quote:
Originally Posted by walford /forum/post/19570057


Since cableTV, phone, and internet sevice use 3 different frequency bands the cable company can install a filter to your service to select which of these 3 services you receive. They do not have filters to block some TV frequencies and not others.

Often a cable company will not do a truck roll to disable basic cable when you drop your TV subscription.

With cable TV not filtered out you will only receive the unencrypted analog channels (2-31) and the unecrypted digital(clear QAM) channels. Unless you subscibe to the encrypted channel(ore set of encryted channels) you want and you have a tuner that will decrypted them.

Actually phone and internet are on the same frequency, forward and downstream. Also more CATV companies are purchasing Traps (Filters) to remove select channels, it's not that hard to order and pinpoint frequencies to remove and stack traps if needed.


Rob
 

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If phone audio service and Internet(IP) use the same frequencies how is it possible to separate them? Please supply a link justifying your claim since IMHO your claim does not make any sense from an engineering prosepetive.
 

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Quote:
Originally Posted by walford /forum/post/19599308


If phone audio service and Internet(IP) use the same frequencies how is it possible to separate them? Please supply a link justifying your claim since IMHO your claim does not make any sense from an engineering prosepetive.

I have hands on experience working for Time Warner; see Local Charlotte Thread and you can read this:

http://www.motorola.com/Video-Soluti...SR_64000_US-EN

http://www.cisco.com/en/US/products/...209/index.html


Cable companies use CMTS/Edge routers and everything is IP based, that's why the phone/Cable modems are one unit.


Rob
 
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