A few weeks after the horrific Sandy Hook shootings Time Warner Cable has decided to take a bit of a stance regarding the NRA handling of the topic of Gun Control.
“We no longer accept ads showing semiautomatic weapons and guns pointed at people,” Time Warner Cable said in a statement. “We stand by this policy. If it’s essential to a business owner to show this kind of imagery in their commercials, there are other advertising options in the marketplace.”
You find the damnedest things in a Cable Ped. Some that make you laugh, some that make you gag, and literally vomit in the grass and some that can kill you.
Here are a few of the above.
Its not uncommon for a critter to be in the ped. The Active are generally warm and cozy. But when you open the ped and the snake, spider, racoon, HONEY BADGER stays put and just stares at you.. you’ve got a precious few seconds to make a decision.
In the last article about Troubleshooting Noise we went over tracking noise and how it affected the return path. The return path is where we generally have our Modems Upstream channels, Box Guide and Hits Data streams and VOD requests. We would do well to take care of all of these by keeping this return path clean and free of any noise greater then -30. In our example we talked briefly about a service call a customer had that various techs had been to but couldnt find the issue. The issue was noise in the return band which was so bad it affected VOD requests. We also barely touched on the small noise spikes in the Forward path that were most likely affecting Digital Video Services. We can cover that now.
Recently there was a job referred to a local maintenance dept. The technician arrived on site for Digital Tiling. He performed all of his tests, Home Cert, Spectrum Check, various QAMs and of course spending time on the channels he was having issues with. He found the affected channels MER to be at 29-30 and BER to hover around 5.00-E-06. This would definitely cause tiling. The tech also noted that it was only on a handful of PODs, or Channels. Everything around these channels were in spec, no issues.
I will skip the details of the troubleshooting that brought the line tech to the actual issue as it is repeating another article you can find by clicking this text. I will say this however, the issue was caused by a Direct TV customer who had fed their Direct TV feed into the homes cabling and also back out to the cable plant. What this did was inject a pretty serious carrier back into the cable plant that caused all kinds of impairments on the QAM channels that were occupying the same spectrum.
In simpler terms, We have a digital carrier on say 549MHz. This carrier holds compressed and encrypted channels like HBO, TLC and we will say ESPN. If another carrier is injected into the plant on this same frequency, or through this frequency it will severely “screw up” the channel we are putting out. This is keeping our plant clean. This is ensuring that cable stays a “closed loop system”. Nothing gets in to interrupt our signal carriage and nothing gets out to affect other services.
The screenshot is the actual carrier. This is a rather large carrier and it occupied the space of about 10 cable PODs which all in all wiped out 50 or so channels. Once the drop was disconnected from the Direct TV sub, the MER popped up to 38, BER was solid at 1.00-E-09 and services were restored. I will try to get a screenshot of our same spectrum and our carriers for the purpose of this example and append them to this article.
Troubleshooting Noise comes up often. Now more then ever noise mitigation is playing an important role in your everyday job. Noise plant wise is a cumulative impairment. A little bit of noise here, a little bit of noise there and the “power” of the noise grows and grows. Its the epitome of the snowball effect. Not only that, it affects the service of single homes as well in a few different ways.
Lets dig in.
Noise has many causes. Things to look for when tracking noise are things you already look for. Loose connectors, damaged cable, chew on the drop, poorly prepped connectors, you name it.
Tracking noise is actually quite simple, at least from the tap to the source in the home. Service techs generally check the Forward and Return for noise in most systems. You arrive on job, climb up to the tap, belt off and start checking for issues. There are two ways to do this. Its best to start whatever habit you want to cultivate now. Im a big fan of having a core routine to troubleshoot by. If Im being thorough Im disconnecting the cable from the groundblock as I enter the yard and screwing on a barrel. This terminates your drop. Now when you climb the pole and check for ingress you will know if you have an issue on your drop or not since it is all you are checking. If you did find noise without doing this you still wouldnt know if it was the drop or coming from the home. You would have to climb down, disconnect the output of the groundblock and check the houses cabling for ingress. And you might see some, the noise you saw could have been from the house and the drop. You wouldnt know.
So lets say you see noise on the drop. Change it. Do not spend too much time trying to find the source. Trying to patch up the drop, just get off of your but and run a new one. As with anything, the more you do this, the faster you will get. See CableTechs “Tips” Article on Running A Drop for tips and tricks. If you do not see noise than perform whatever other tests you are running and head to the groundblock. While you are unscrewing the barrel from the drop run the Spectrum test at the Groundblock going into the house. BAMMO! Ingress! Great- Lets get to troubleshooting shall we?
In this scenario- a real one- we have a customer who called in for a VOD issue. They are having trouble ordering VOD and this is their 3rd trouble call. You open the housebox and see a brand new splitter and connections, the past techs did their job. Or did they? You run your Spectrum test on the 4 way splitter and you see noise. In the graph to the left, the actual screen shot from this trouble call from over 3 years ago, you see the noise. Most MSOs have a threshold of -30 for noise. You can see the “Peak” is at +1dB around 90MHz. In the screen shot above the marker is at 40MHz to isolate where our return path is. You can see the high noise all the way to the left.. that just so happens to be the same frequency range our cable boxes talk back at. The same range our VOD requests shoot out at. There are also noise spikes further to the right of the spectrum which is also in our Digital Channel range and can cause tiling. ( this is why we do not just check the return on service calls) This is most likely our issue. So how do we track and fix?
You start by removing the outlets off of the splitter one at a time until the noise disappears. When you unscrew the outlet that causes that noise to drop, that is the one you follow. In this case it lead to another splitter. A two way. We follow the same procedure. Put our meter on the input and disco each outlet until the noise disappears. Follow that outlet. We are lead to a second story bedroom with a crawlspace. In the crawlspace we find a “Radioshack” gold splitter with frayed connectors, loose crimps and quarter turned connectors. Only three of the four ports are being used, the last unterminated. The outlets in this case were also all antennae line used for Cable by the sub. At this point you provide the option- Replace your DIY job for whatever the cost is by your MSO or remove the splitter, barrel up the lines and let them know the noise is gone but if it returns they will need these lines replaced. The image to the right is the actual splitter and connections that caused the noise in the preceeding image.
Now that is basically what you will come across all day. Noise sources however can be intermittent. These are the worst. Its at this point you employ a few different techniques. Have the customer turn on all TVs, maybe ask what they do before they watch TV, make coffee, do the laundry etc. It is not uncommon for a loose connector or damaged piece of cable to show no issues until something it is close by injects noise into it. A blender, Refrigerator, TV, Surge Protectors, lights on timers. Another call had me at a customers house at 7pm when they stated it tiled like clockwork. I stood in their living room at 7pm and sure enough it started tiling. What else happened at 7pm that I was able to see out of the corner of my eye? Their porch light turned on automatically. I go outside and see a stapled line running along the eaves above the porch light. Bingo.
Another method is the return ingress test. Ill have to save that for another post however.