atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Outside Plant OSP Construction Outside pedestal related to cable tv and internet signal strength?

Hello.

I am not sure if anyone here would have knowledge of this subject but I had some questions about the outside pedestal in regards to cable services.


1. The different levels of cable service are simple a matter of adding/removing the correct filters to the line.


2. Is signal strength determine by any changes in the pedestal or is that amplified after it goes inside the house? In other words, is there are a weak signal would it require changes to the cable once it entered the house( possible with an amp) or would it require a change be made to something inside the pedestal?

3. The wiring between the pedestal and the house consist of 1 coax cable which would be considered the master input feed correct. This input feed must then be distributed to the various cable outlets in the house possible by connecting to a large cable splitter?

That is my understanding on how this entire system works. Please let me know if I have a correct understanding of it or if I am off base.

Thanks.

Well, ....Yes, but ......No.

As I am a telephone man, not a cable guy (no, my name isn't Larry), I am no expert but normally the main line cable has amplifiers every so far and the signal is "hot" and drops due to distance and load (that is your reciever). Now days the signal allowances are not filters but digital signal allowances. The old days, filters.

Now, if you want the exact info, I'm sure Hal or Ed will be by before long.

The signal coming out of the pedestal is determined by amps throughout the cable companys system and what kind of tap is in the pedestal. The drop cable that comes to your house is tested to see if it is adequate for your services. If the signal is to low the provider will put in a small house amplifier and hook up all of your tv's and other equipment to a splitter. As far as the different levels of cable service, we use devices called traps to block out services that you do not have. That is pretty much how it works in a nutshell.

Hello.

Please let me know if I understand it correctly from what I have read from your post.

The cable travels through many amplifiers before it actually reaches the pedestal in front of the house.

There is no individual amplifier inside the each pedestal in front of a house.

The Amplifiers are complete separate boxes from the pedestal which are only used to the amplify the signal and nothing else.

These amplifiers along the way do not have adjustable setting but rather just amplify to their max all the time.

Therefore if the signal coming into your house is too week. The only option is add a personal amplifier inside the house.

There is no option to increase or decrease the signal from the pedestal itself. The feed is simple:
1.Turned on or off
2.Different levels of service(not signal strength) are controlled by various filters/traps on the cable line itself.

Please let me know if this is how it work or if I am still off base on the concept.

Thanks!

Diagram of cable network

Line extenders (A.K.A. amplifiers) exisist at many points among a CATV route. These are quite different from an amplifier that you buy at Radio Shack, since they do a lot more than just amplify the signal. Line extenders actually repeat the signal and many times, DC power is inserted into the cable run to compensate for voltage drop, hence the name extender
.
These are the fairly large bolted rectangular aluminum housings that you will see along aerial runs near poles. LE's can also be installed in pedestals, but only the larger ones and the pedestals typically include ventilation louvers to aid in heat dissipation. The dinky distribution pedestals (6" square or so) only include taps, or "splitters".

LE's have to be adjusted to compensate for temperature swings on a regular basis. Since metallic conductors offer more resistance when they are hot and less when they are cold, this is a constant maintenance issue for CATV companies.

Filters within pedestals are generally used to simply block subscribers from gaining access to channels or services that they aren't paying for. Nowadays, digital cable is becoming the norm, so the addressing of the cable receiver boxes actually control what you get and what you don't.

If you have more than four cable runs to sets, you probably should consider your own "personal" amplified splitter. Long cable runs, especially when done with low-quality builder's grade COAX cable are usually the culprit for poor signal quality. In addition, the electricians who install these cable runs frequently lack the proper crimping tools. They simply "mash it with their Kleins". This distorts the dielectric insulation and causes all kinds of wacky performance.

You can amplify the signal this way, but if the outgoing cables are bad, or poorly-terminated, you will see random performance. If the incoming signal is bad, then you will experience similar performance from all devices connected behing the amplified splitter.

There is a very good chance that your signal coming in is actually too "hot". An especially strong signal is just as bad as a weak one with regard to picture quality or Internet connectivity.

Thank you ev607797. That was an extremely detailed explanation on how the system works. I think I have a much greater understanding of how the process works outside the house leading up to the pedestal.

I was wondering if I could ask another question dealing with issues inside the house.

1. Would I be correct is assuming there is a single input cable which feeds cable all outlets in the house?( not multiple cable feeds). This is for a residential setup not a building.

In other words, all cable outlets in the house will eventually go into a common splitter/personal amplifier most likely in a utility room located inside the house. This common splitter probably will have 1 master input cable feed running from the house to the pedestal.
This 1 feed cable is what powers all the television outlets in the house.

2. When wiring additional rooms for cable TV(assuming current TV and cabling setup works fine).

Would there be a need to make any adjustments in the pedestal? I am assuming that if the signal is weakened by the additional load, it would probably require an stronger personal AMP before the splitter correct?

* As a side note: I am not talking about cable that requires a digital box receiver, simple cable plugged into a regular TV.

Thanks.

The signal coming from the pedestal will always remain roughly the same. From the pedestal, you will have one feeder cable coming to your house. It will usually end up in a utility room. From there, all of the house cabling should go to one splitter. If their is not enough signal for all of the devices, then a house amplifier will need to be added. With a simple 10db amp, we have people running 16 devices with no problems at all. This includes digital phone, internet, and multiple digital boxes.

Thank you, Shannon. I still think of you as a telephone man, not a new "Larry".

You guys are good......

Still learning the new trade, but I have enough knowledge now to be dangerous.

That is exactly my understanding of how it works.This is also exactly what I am seeing in the utility room. I had someone tell me once that each outlet has a cable going to the pedestal which did not make any sense.

Anyway, I was wondering does an over amplified signal act the same way as a weak signal in the event that the amp is too powerful?

Thanks for your help.

I'm not a cable TV guy, but yes any signal can be overdriven.

A weak signal will usually give you a snowy picture. If the signal is to high you will usually get what is referred to as ghosting, which is a double image.

I had an interesting problem where the signal levels coming into my house were way too high, the cablemodem was reporting a low S/N ratio, and the analog TV pictures looked noisy.

As far as I could determine an amp somewhere was being overdriven. I called Comcast and they sent someone out who confirmed that the signal levels were way too high and that the problem had to be referred to a line tech.

It took Comcast only two weeks to fix the problem, during which time the cablemodem pretty much didn't work. I called up Comcast to complain about the situation and they basically gave me a $240 discount on my bill ($20 over 12 months).

This was about 2 years ago. I sure hope their response time is a little bit better now that they're in the phone business.

I have heard a lot of problems about comcast.


1. One person was signed up for Internet however it was not working because comcast had a outbound filter on the line in the pedestal. The tech removed the filter and the internet worked. They got a bill for $50 saying " failed self installation". Comcast customer tech support out not remove the charge.

What did they expect the customer to do? Pick the lock in the pedestal and remove the outbound filter? Is that what they consider a self-install?

2. Randomly charging leases for cable modems: I have heard of customer being randomly charged leases for cable modems out of the blue. Comcast will just assume(sometimes at random) to charge a lease for a modem without any idea if they own it or not. They will demand you provide then with a receipt faxed to them and will not remove the charge. They do not look up the serial number of their modem against a database, just make assumption that all modems are leased by them.

3. Being charged additional outlet installation fees without even installing or even so much as touching the line. Comcast tech pluged and removed from filter in the pedestal, when in the utility room to check the master input cable feed. Then counted the number of cables he saw on the splitter and charged the customer as if each outlet had been installed by him when they were not even touched.

4. Hurricane took out internet service for 3 weeks in the Florida residence. The problem was completely documented and effected all the houses on the street. comcast however a credit was only given for 1 day because they said the customer did not call ealier. Customer said " there was a hurricane and I kept seeing your trucks working on the box outside, I assumed you were on the problem"

I am sure there are a lot people with a lot of horror stories about them.

They wouldn't have had to pick the lock, in most cases..

I can't count the number of unlocked or smashed-up pedestals I've seen all over the place. Cox, Comcast, it doesn't much matter. They apparently no longer care about cable theft.

In this neighborhood, which is about 15 years old, Comcast has bypassed bad sections of underground hardline with RG6 run along the ground several times. In one particular case they ran it across a street and two sidewalks. The city made them remove it (after 3 months!!), but I doubt they ever replaced the bad hardline--they didn't use conduit and I never saw any trenchers, backhoes, or other heavy equipment.

After almost tripping over ANOTHER RG6 they ran across the ground I popped open the pedestal and observed that the cut-off stub of underground hardline they bypassed appears to be missing the flooding compound.

I wonder if that could account for the problems they're having? Last time we had a good rain for a couple of days my cablemodem's transmit power was bouncing all over the place...

Well, not to defend these guys, but they did assume several operating networks here in Virginia that were originally installed by "Mom and Pop" cable providers. In my area, it was Prestige Cable that was later purchased by Adelphia. We all know the story about Adelphia. Comcast has since taken over their territory in my neck of the woods and to be honest, some two-year old problems that I had were fixed rather promptly.

True, there are tons of above-ground temporary fixes here too. I think that they have a lot of catching up to do after having been left with such a rinky-dink infrastructure. Now that these networks are carrying voice and data traffic, cable TV service is no longer considered a luxury. It's a utility and the regulatory bodies are starting to treat the cable companies that way.

I agree about the pads in the LE's (amplifiers) needing to be replaced to compensate for cold or hot temperatures. I went through that with Prestige and then Adelphia for years. For the most part, my service has been stable for the better part of a year and to be honest, the service offerings are much better. Yes, the rates went up when Comcast came to town, but you get what you pay for in my opinion. Prior to the take over, our services sucked.

This used to be a Jones Intercable area--I remember when Cablevision of Manassas sold out to Jones Intercable, it was around the time this neighborhood was built. (I did the computer inventory for Cablevision of Manassas as part of that sale).

What's ironic is that I used to live in an older part of Manassas, built in 1983 before Manassas got cable, and I never had any problems there, despite the cable in the ground being likely 10 years older.

Since I moved to this neighborhood, it's been nothing but problem after problem after problem. In fact just today the transmit power on my cablemodem shot up to 60.8dBmV (from 43dBmV) and stayed there for 30 minutes, after it dropped offline and resynced. This has been an ongoing issue since May. They attempted to fix the problem by putting a lower value tap in, and yes that did help, but the wild power swings are still happening--they just don't knock the modem offline as much.

I've had multiple techs out to my house who can't do anything about the problem because it's a line problem--replacing modems, splitters, and cables isn't going to fix a problem that is clearly between the tap and the node.

I guess my only hope for getting this fixed is that whatever is causing the problem gets blown out by lightning so it has to be replaced...

...and these jokers are offering phone service? Hah.

That’s because the subs get paid by piece work, in addition to the install; a wall-fish here, a termination there and so on. They see easy money in a properly pre-wired house.

I was having problems with an internet self-install. I could see some kind of trap on the pole/tap and figured this is why the modem would not come on line. Anyway the customer had to call out a tech, which seemed to rectify the problem. When the customer had us return to finish up, I noticed a splitter on the counter, keep in mind we wired the house. I asked where this came from and they stated that the Cox tech removed and put on there's, this being the problem with the internet. So I took there’s off and replaced with the one from the counter and all was working fine. BTW the trap on the tap was missing. I suspect the customer got a bill for the splitter.

I'm in a housing developement that changed from Adelphia to TWC 11/06. They got REAL busy and we had digital throughout the old Adelphia analog infrastructure by 3/07. Got my cable hi-speed early April, but I passed on the phone, they still only have about 94% up-time, and I don't have a cell backup. Surprisingly, Sprint-now-Embarq has been extremely reliable, even out here in the 'country', and they started offering DSL 9/06. But the faster cable service was coming so I waited. The only complaint I have is that when TWC laid in a new cable to upgrade my drop for digital, they seem to have 'trenched' my septic tank laterals, I discovered last week, while doing some other 'homestead' investigation. I suppose this will wind up being a $$$ nightmare! Guess that will be determined after the county confirms my suspicions. John C.

How deep did they go? I've never see TWC bury a line here deeper than 12 inches. Good luck though getting them to correct anything on it. They'll probably say it was your responsibility to mark it.

Guess what, I got the COUNTY on my side and they've been down the road a lot about this lately. I just need to fill out the county's paperwork so they can come out and check for damage. If there is a problem,THEY go to bat!! D-MN, I'm FINALLY getting something for my taxes! Interesting thing is what's going to happen about the original Adelphia damage, if any. It's in a different place though, only a couple of feet from the supposed end of the laterals. John C. (Not Garand)

Lucky you! People out here have a hard enough time getting TWC to replace the grass they dig up.

I haven't really thought about why the county is so interested until now. But, I suppose it has something to do with ground water pollution? Possibly some sort of state or federal law they don't want to have to deal with in court. But, like I said, it's about time my taxes did something for ME! John C.