More Signal Problems

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Crash2009

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More Signal Problems

#1

Post by Crash2009 » Thu Nov 22, 2012 2:14 am

So its been a couple months with the BDA-S4 installed. The Samsung is hooked up to a STB (DCX3400) gets a slight bit of pixelation once in a while. The Ceton has been running great. I finally had time to actually watch one of my recordings the other day and 1:29:00 in to the movie, captured this little blip.

Is this pixelation again?

So, anyway, I call up Comcast, and tell them about all the money I spent getting ready to receive and record their service, and all the money I am about to spend on streaming their recordings around the building, and wham, first movie I watch has this kind of crap right in the middle of the movie. So their best idea was that I make an appointment with a line tech. Yeah, the tech with the 10,000 toy.

The tech shows up on time, seems like a pretty good guy, comes in and says "What's the problem?" so I take him over to the DCX3400 and tell him I got a bit of pixelation on the Samsung. He removes the coax from the DCX3400 and hooks it up to his machine, and says "Holy S___, this one is smokin" I gathered that the signal strength was a tad high when he said "Where is the amp?" I take him over to the amp and he tests the line in, and reports that the signal is "within range". I gather that means tolerable but not perfect.

I explained to him that his co-workers originally installed this place with four 2-way splitters, and because of that, the Ceton was getting -11 dbmV on some channels, and, because of that, my whole WMC/Ceton experience was not very good. His explaination was that the amp is smoking the DCX3400, and if the Ceton needs better than -11, maybe I should amp the Ceton. He proceeded to uninstall the amp and replace it with a 4-way splitter. Well of course everything else worked except for the Ceton. So I tore his S___ up and installed it the way I had it.

Six hours later, I finally got it back together again. It was a calamity of errors. He unplugged the Ceton during a pre-programmed recording, the signal strength (or lack of it) caused a couple more errors, somehow my computer time lost an hour, the time screwed the guide, and in the end-6 hours later I decided to re-boot and there was Adobe trying to update. Adobe updated and everything was fine after that.

Sorry to vent, I just wanted to document the unpleasant experience with the $10,000 toy.

I just remembered one more thing. He says I don't have a signal problem. He says the problem is with the source of the movie. In other words Comcast has delivered what it received and passed it on to me. So if Cinemax is the source, and the source copy is no good, I should get the same blip in the same spot, if I record it again. Right?
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Last edited by Crash2009 on Thu Nov 22, 2012 3:51 am, edited 1 time in total.

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Crash2009

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#2

Post by Crash2009 » Thu Nov 22, 2012 2:26 am

So I recorded the same movie again, skipped through to 1:29:00 and no pixelation this time. Get on the phone to the CableCard department. and after a little bit on hold I get Chuck from tech support. Whew! What a relief, finally found somebody that knew what they are talking about. Understood the problem, and agreed that I have had signal problems since day one. Agreed with me that you don't have to order the HD part of things to have a clear picture. We both had a laugh at the front line reps that solve signal problems by selling more equiptment. Chuck figures that I have an intermittent signal problem between the house and the pole, and is sending someone here Saturday. He said at this point there is no gaurantee that the tech will find it this week, but its on record at least that there is a problem, and it will be corrected.

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#3

Post by olyteddy » Sat Nov 24, 2012 6:13 am

Crash2009 wrote:So its been a couple months with the BDA-S4 installed. The Samsung is hooked up to a STB (DCX3400) gets a slight bit of pixelation once in a while. The Ceton has been running great. I finally had time to actually watch one of my recordings the other day and 1:29:00 in to the movie, captured this little blip.

Is this pixelation again?

So, anyway, I call up Comcast, and tell them about all the money I spent getting ready to receive and record their service, and all the money I am about to spend on streaming their recordings around the building, and wham, first movie I watch has this kind of crap right in the middle of the movie. So their best idea was that I make an appointment with a line tech. Yeah, the tech with the 10,000 toy.

The tech shows up on time, seems like a pretty good guy, comes in and says "What's the problem?" so I take him over to the DCX3400 and tell him I got a bit of pixelation on the Samsung. He removes the coax from the DCX3400 and hooks it up to his machine, and says "Holy S___, this one is smokin" I gathered that the signal strength was a tad high when he said "Where is the amp?" I take him over to the amp and he tests the line in, and reports that the signal is "within range". I gather that means tolerable but not perfect.

I explained to him that his co-workers originally installed this place with four 2-way splitters, and because of that, the Ceton was getting -11 dbmV on some channels, and, because of that, my whole WMC/Ceton experience was not very good. His explaination was that the amp is smoking the DCX3400, and if the Ceton needs better than -11, maybe I should amp the Ceton. He proceeded to uninstall the amp and replace it with a 4-way splitter. Well of course everything else worked except for the Ceton. So I tore his S___ up and installed it the way I had it.

Six hours later, I finally got it back together again. It was a calamity of errors. He unplugged the Ceton during a pre-programmed recording, the signal strength (or lack of it) caused a couple more errors, somehow my computer time lost an hour, the time screwed the guide, and in the end-6 hours later I decided to re-boot and there was Adobe trying to update. Adobe updated and everything was fine after that.

Sorry to vent, I just wanted to document the unpleasant experience with the $10,000 toy.

I just remembered one more thing. He says I don't have a signal problem. He says the problem is with the source of the movie. In other words Comcast has delivered what it received and passed it on to me. So if Cinemax is the source, and the source copy is no good, I should get the same blip in the same spot, if I record it again. Right?
So I have to ask, if everything but the Ceton worked perfect after removing the amp, why didn't you just amplify the Ceton feed? What's your background that you can second guess the cable tech?

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#4

Post by richard1980 » Sat Nov 24, 2012 7:40 pm

Having only four 2-way splitters is a terrible idea. It gives you 5 outputs, but there are three possible attenuation scenarios (depending on how its wired), none of which are any good:
  • One output attenuated 3.5 dB, one output attenuated 7 dB, one output attenuated 10.5 dB, and two outputs attenuated 14 dB.
  • One output attenuated 3.5 dB and 4 outputs attenuated 10.5 dB.
  • Two outputs attenuated 7 dB, one output attenuated 10.5 dB, and two outputs attenuated 14 dB.
It doesn't matter how you wire it, you'll be dealing with at least 7 dB of swing and at least three outputs with no less than 10.5 dB of attenuation. To put it bluntly, that's just stupid and the person that wired it that way doesn't know WTF they are doing.

That said, replacing the four 2-way splitters with a BDA-S4 is not the right answer either. The only reason you would need an amplifier is to counteract all the attenuation caused by the splitters. If you don't attenuate the output of the BDA-S4, you'll end up with too much amplification.

To do it correctly, you need to connect the BDA-S4 to the incoming line. The connect a 4-way splitter to one output of the BDA-S4. The BDA-S4 amplifies the output by 7 dB, and the 4-way splitter attenuates the signal by 7 dB, for a net change of 0 dB. Alternatively, you could connect a 2-way splitter to one output of the BDA-S4, then connect each output of the 2-way splitter to another 2-way splitter. The first 2-way splitter will attenuate the signal by 3.5 dB, and the second 2-way splitter will attenuate the signal by another 3.5 dB, for a total attenuation of 7 dB, again for a net change of 0 dB. That's assuming the incoming line doesn't need to be attenuated any further. If it does, just adjust the amount of attenuation at the output of the BDA-S4. And if the incoming line needs to be amplified, you'll need to contact the cable company and have them amplify it before it gets to your home, then adjust your attenuation accordingly. Ultimately you want to your signal strength across all frequencies to be centered around 0 dB.

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#5

Post by olyteddy » Sat Nov 24, 2012 10:12 pm

Ultimately you want to your signal strength across all frequencies to be centered around 0 dB.
True, but most devices can tolerate levels of +10dB to -10dB. Some work well at even lower than -10dB. My HDHR Prime is running fine with some channels as low as -14dB and my modem at -10dB.

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#6

Post by barnabas1969 » Sat Nov 24, 2012 11:54 pm

My cable guy installed a 9 port amplifier that outputs 0dB (unity gain) on all nine ports. Eight of those ports are in use (I have a lot of outlets in the house... see below), and the 9th one is capped with a 75 ohm terminator. The amp is ginormous... the biggest cable amp I've ever seen... must cost a fortune (free for me!). It fills the entire gray box on the side of the house... and my signal has never been better.

My outlets:

2 in the wiring closet: one wired to the cable modem, one connected to a 2-way splitter that feeds two Tuning Adapters... and the outputs of the TA's are connected to my two HD HomeRun Primes.

2 in the master bedroom. One is capped with a 75 ohm terminator, and the other is connected to a TV.

One in each of the other three bedrooms... all connected to TV's.

One in the living room... connected to a Hauppauge clear QAM/NTSC tuner in my HTPC.

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Crash2009

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#7

Post by Crash2009 » Sun Nov 25, 2012 1:09 am

[/quote]So I have to ask, if everything but the Ceton worked perfect after removing the amp, why didn't you just amplify the Ceton feed? What's your background that you can second guess the cable tech?[/quote]

It was just a hunch. My spidey sense was tingling towards the end of our encounter. Plus, he left me with a mess to clean up. If he was unfamiliar with CableCard setups, I think he should have backed out or called in re-enforcements.
Last edited by Crash2009 on Sun Nov 25, 2012 1:50 am, edited 1 time in total.

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#8

Post by Crash2009 » Sun Nov 25, 2012 1:31 am

[/quote]To do it correctly, you need to connect the BDA-S4 to the incoming line. The connect a 4-way splitter to one output of the BDA-S4. The BDA-S4 amplifies the output by 7 dB, and the 4-way splitter attenuates the signal by 7 dB, for a net change of 0 dB. Alternatively, you could connect a 2-way splitter to one output of the BDA-S4, then connect each output of the 2-way splitter to another 2-way splitter. The first 2-way splitter will attenuate the signal by 3.5 dB, and the second 2-way splitter will attenuate the signal by another 3.5 dB, for a total attenuation of 7 dB, again for a net change of 0 dB. That's assuming the incoming line doesn't need to be attenuated any further. If it does, just adjust the amount of attenuation at the output of the BDA-S4. And if the incoming line needs to be amplified, you'll need to contact the cable company and have them amplify it before it gets to your home, then adjust your attenuation accordingly. Ultimately you want to your signal strength across all frequencies to be centered around 0 dB.[/quote]

Tech # 3 (the one that was here today) saw it your way Richard. The DCX3400 was getting too much so he installed a 4-way just before the DCX3400. Also he asked me if I needed to shut anything down on the HTPC before he disconnected the line. No errors this time, and no mess to clean up.

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#9

Post by Crash2009 » Sun Nov 25, 2012 2:09 am

Everything checked out good today. Tech 3 could not find enough evidence to order a line check from the house to the pole. Even though I had a recording from 10-11-2012, with a precise time of the pixelation 11:47am. He did phone somewhere to see if they had any records for that date. I was told they only keep log files for 7 days.

Does the Infini4 or WMC log pixelation events? or signal events?

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#10

Post by Crash2009 » Sun Nov 25, 2012 6:12 pm

Looks like my most recent pixelation problems are self inflicted. I ordered the wrong amp. I should have ordered something with zero loss/gain, or better yet, convinced Comcast to put one in for free. I conducted a little experiment this morning using a 4-way and a 2-way splitter in line just before the Infini4. Tuned the channels using The Ceton Diagnostic Tool, then displayed the results using the Ceton temps tool. Entered the results in an Excel spreadsheet, and now I can plainly see what you all are talking about. The old way it was hooked up (4 or 5 daisy chained splitters) was just plain wrong. Tossing all the splitters and installing the BDA-S4 was a step in the right direction, but as we can see not an ideal solution.

I think what woke me up was the results of channel 275. I have a perfect signal on that one. It doesn't get any better than zero. Then I amped it +7 and now I have to 4-way it (-7) to cancel the +7 to get back to zero. What was surprising to me is the results of installing the 2-way. It appears HBO would prefer the 2-way. I think I understand now, what Tech #3 was talking about when he said take the highest and lowest and shoot for the middle.


Barnabus, Richard, how did you guys get so smart?
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#11

Post by barnabas1969 » Sun Nov 25, 2012 7:38 pm

Yes, shoot for the middle. And I'll add that it is not a good idea to add extra splitter in the line in an attempt to attenuate (lower) the signal strength. Each splitter also degrades the SNR (Signal-to-Noise-Ratio, or quality).

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#12

Post by Crash2009 » Wed Nov 28, 2012 1:54 am

I just got off the phone with Bill Odennell, an engineer at PCT International. They manufacture a unity gain amp with a special port for the voice cable modem. The model number is PCTVC9U http://www.pctstore.com/ProductDetails. ... de=PCTVC9U

I have pretty much given up on Comcast, they are such a waste of time, 3 times on site here (6 hours), numerous phone calls, I am sick of dealing with them. Hopefully this new amp will balance things out.

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