Cable TV Reception Improvement - PeachParts Mercedes-Benz Forum

sunedog · #1 06-13-2008, 07:01 PM

Anyone care to provide some tips on how I can improve my cable TV reception?

I have TW Cable in a 19 year old house. The cable comes into the house immediately to a 3 way splitter. One leg goes to a RoadRunner cable modem, another to a 42" plasma HDTV in the basement and the third goes to yet another splitter. That downstream splitter provides the signal to 4 other TV's on the upper floors. The picture on the plasma TV is gorgeous and the broadband cable works with no discernable hiccups.

The upper floors have original wiring (RG 59?) and the terminations are not something I'm proud of. The reception on the TV's upstairs is poor. Some lower staions are acceptable, but the channels in what I'll call the mid-range (45 - 72) have a lot of snow. TW has been out a couple of times and done what they think is their responsibility. I'll have to pay them their hourly rate to probe further.

I finished the basement 8 years ago so the RG 6 wiring is newer and the terminations are better.

I suspected the wiring and terminations were the culprits. Since I've got half a spool of RG 6 left over, I decided to do an experiment. I cut a piece of coax long enough to run from the cable entry point directly to the farthest TV. I read up on terminating coax, bought a professional crimping tool and carefully terminated the ends with crimp connectors. I planned to just disconnect each TV's cable at the splitter and temporarily connect it with the new cable to see if the picture was better. If it was, I'd figure out a way to permanently run new wire to those wall outlets.

To my surprise, when I connected the temporary cable, I lost the signal on every TV in the house. So I reversed the experiment and reconnected everything back to the way it was before I started. Still no picture on any TV.

I was really scratching my head here, but finally disconnected the main cable where it connects to the first splitter, waited a few moments and then reconnected it. Voila...TV pictures again.

1. So what did my experiment do. Clog up the electrons in the "pipe?"

2. How would you start down the path to improve the reception?

Larry Delor · #2 06-13-2008, 09:49 PM

Have a tech come out, and check the signal strenght. They [cable companies] keep adding volume to a pipeline that's already full of stuff - so, they may have to climb up on your pole, and take out a [whatchamacallit] or change out an aged trap filter. (trap filters is what some cable co's use to give you channels up to a certain number, and "filter" out the stuff you don't pay for)

If you can get Fiber, go with it - you will be amazed at what TV looks like in the 21st century.

Mistel · #3 06-13-2008, 09:57 PM

I'll take a stab at this.

Is it possible that when you did your test, that you disconnected the cable input? Are you certain which cable is which? I think a splitter would work no matter which way the cables are attached. I think you can buy a booster for you cable. I know for my sattelite dish I have to run it through a booster as I have 4 TV's with 2 input cables.

iwrock · #4 06-13-2008, 09:59 PM

Its that second splitter. If its inferior to low quality, it will degrade the quality heavily.

Make sure its a nice one, and make sure it does 5mhz to 2.4ghz.

sunedog · #5 06-13-2008, 10:03 PM

Quote:

Originally Posted by Mistel

I'll take a stab at this.

Is it possible that when you did your test, that you disconnected the cable input? Are you certain which cable is which?

I'm certain that didn't happen. The incoming cable is clearly visible where it pokes through the foundation wall.

MTI · #6 06-13-2008, 10:27 PM

Also, check the rating of the splitters that are used to create the cable wall outlet. TWC switched out all our older splitters behind the wall plates.

When we switched to HD, I had to add a Motorola Cable Amp to boost the signal to the HD-DVR to eliminate break ups in the signal.

mgburg · #7 06-14-2008, 03:22 AM

First off, check the BANDWIDTH (BW) of the cable that's in your home...
Start with the I/P cable from the cable company...EVERY channel should be at the same level coming into your home...right out of the cable itself...if not the same level, they should be able to document where the "roll-off" starts and to what level that "roll-off" goes until there's no picture...
Next step...assuming that the level is correct from TWC, you need to see what the BW is of EVERY COMPONENT in the chain...start with the first spliter, then be sure that every run OUT of the splitter is receiving the same level signal at each O/P. Be SURE that the I/P of the splitter is actually an I/P and the O/Ps are just what they're suppose to be...do not assume that an I/P and O/P can be interchanged...they can't and shouldn't be...(There is an exception to this rule, but for the sake of getting this straightened out, we'll leave that alone for right now...)
Out of each O/P, follow each run to it's intended TV...be sure there are no splices, barrel-connectors and "repaired breaks" in the line under test. Each and every step can introduce a "problem" that will drastically effect the quality of the signal being fed to your sets...
When checking the BW of the cable, get as much information from the jacket of the cable and you can then use that information to get on-line and get the specs. from the manufacturer themselves...here's what to look for:

The cable should be able to pass all frequencies from a low of 5 Megaherts all the way up to, or better than 1000 Megaherts (1 Gigahertz). If it doesn't, seriously consider replacing it with cable that does.

Based on your comment about the house being 19 yo, that may be your problem.

MANY YEARS AGO, cable companies (CCs) NEVER would have guessed that there would be a need for more BW or more channels...most systems started out and were wired for no more than 30 channels, tops.

So, as customers demanded more channels, CCs were forced to put more channels on, usually pressing their infrastructure beyond the original engineering designs.

And, since most homes were originally wired by the CCs themselves, the CCs didn't necessarily use the best and most robust cable available...most times, they used whatever happened to be on "closeout" or some fly-by-night cable manufacturer "specials" - usually pennies/ft. - vs. - 10-15 cent/ft. for the better stuff...and BW? Who cared? Connectors? Who cared? If the cable went bad, you just blamed the harried mother w/10 carpet-crawling ankle-biters and charge for a service call to "fix" the damaged cable...not IMPROVE, just replace crap cable with the same, or cheaper, crap cable. (And they wonder why people are more interested in Satellite Dish systems and they keep loosing customers?

)

Another thing to check for...remove any amplifiers that are on the string...In the digital world...too much signal can, and will, cause problems VERY SIMILIAR to too little signal. For example: The digital picture will go black or pixilate if the "front end" of your set is over-driven by too much signal...and it will look just like having too little of signal...the decoder in the set will see the extra signal as distortion and the corrupted "ones" and "zero" will mean nothing to the decoder - so then the picture will go "bye bye" - have the technician measure the signal from each O/P of the splitter and then connect the cable onto the splitter, then measure the signal level at the far end terminal...there will be a small signal drop (on the order of 1-2 dB., but it shouldn't be much more than that. If it is, then the cable in between the splitter and jack near the set is the suspect in the signal quality issue. BTW, when the O/Ps on the splitter are measured, there should be no more than a 1dB. difference between each O/P...if there's more, you should replace the splitter...smash the faulty one (You'll never mistake it as a good one to use elsewhere!) and retest the replacement unit like you did before...most problems are usually the splitter or cable itself.

PM me if you need further information on what to look for with your troubleshooting of the system.

Good luck.

sunedog · #8 06-14-2008, 10:02 AM

Quote:

Originally Posted by iwrock

Its that second splitter. If its inferior to low quality, it will degrade the quality heavily.

Make sure its a nice one, and make sure it does 5mhz to 2.4ghz.

This might be the problem. It's from a home center or possibly Radio Shack and I'm sure only cost a few bucks.

Both the 3 way splitter TW provided and my 8 way splitter have labels indicating they are 5 MHz / 1 GHz.

So what kind of splitter do I need and where can I get it?

================

UPDATE: I typed the above last night. When I went to the utility closet to check the specs on the splitter, I held the splitter in my hand (did not disconnect anything) and Voila...lost signal to all TV's, digital phone and broadband cable. Tried the disconnect main line trick several times and no luck. So I called TW cable. They sent a tech out this morning.

Diagnosis: Bad splitter (their 3 way splitter). I guess just touching it finally killed it. Reception is much better upstairs. Not perfect yet, but better.

So I'll probably try my new wire experiment again.

Thanks for the replies.

sunedog · #9 06-14-2008, 10:06 AM

Quote:

Originally Posted by mgburg

First off, check the BANDWIDTH (BW) of the cable that's in your home...

M. G. -- Wow. Thanks so much for providing great information. I need to spend some time with your post and do some studying and checking. Just don't have time now. The lake is calling.

BobK · #10 06-15-2008, 08:21 PM

Hey MG, thanks for the reminder about the new cable bandwidth. When I started fooling with this stuff, nobody ever dreamed of going that high. I think they needed about 300Mhz. I'm about to (re)wire my new house for cable AND over-the-air tv. What cable brands/model numbers are you favoring?
Oh Sunedog, remember to terminate every port on the splitter.

mgburg · #11 06-16-2008, 10:57 AM

Quote:

Originally Posted by BobK

Hey MG, thanks for the reminder about the new cable bandwidth. When I started fooling with this stuff, nobody ever dreamed of going that high. I think they needed about 300Mhz. I'm about to (re)wire my new house for cable AND over-the-air tv. What cable brands/model numbers are you favoring?
Oh Sunedog, remember to terminate every port on the splitter.

First, PLAN YOUR SYSTEM before you go out and buy ANYTHING!

TOO much of anything in this area is going to hurt you...

If you're only going to have a maximum of 3 TVs/Monitors hooked to the system at any one time, don't buy a 4- or 5-port splitter...ONLY A 3-port is needed...each additional port BEYOND WHAT IS NEEDED knocks the O/P signal level down, exponentially...2-port, half the signal; 3-port, half of the half of the signal (1/4 of the signal I/P or 6dB. down); 4-port, half of the half of the half of the I/P signal (1/8 or 9 dB. down) - that's a constant...

Nothing wrong with wiring every orriface of the property...just don't hook it up all at once and leave the ends unterminated...

As for cable...

Expect to pay for the good stuff. But, to get the good stuff, you need a little knowledge...

First, make sure the cable you get is "frequency-swept" (FS) for the purposes you are intending to use it for...don't buy/pay for more than you'll ever need, but don't purchase the first batch that falls off the truck either.

If you're intending to wire for cable, and your CC has some decent technicians that actually talk to the customers and will respond nicely to honest questions, find out what frequencies they're using to transport the signals to your home...That's the first step.

Second step...if the CC techs. are still in a good mood, find out where they get their in-house cable from...and see if the field techs might even give you their "box-ends" (there's a term I heard a tech use one time...but for the life of me I can't recall it right now...) - these pieces are usually 50' - 90' and are too short for them to use in certain circumstances...they usually have 9 or 10 boxes a week that they just toss out...maybe that will save you a little cash...but remember, no splices from the CC-I/P terminal to your set..."home runs" are what you want ("Home-run" is a cable that is pulled from the main distribution frame (MDF) area of the home/business all the way to the terminal gear (phone/TV) and has no other intermediate distribution frames (IDFs) or splices in it...it's just one L-O-N-G piece of cable.)

Now, if you can't get ahold of any freebies or the CC techs. are non-existent in your area, think carefully about how many channels you are looking at getting at your residence, or what is the maximum service you can expect to get. General rule is this...for EACH channel on the service, you multiply that number by six (6) and add 300 to the product to get the answer in Megaherts (MHz.)...

Example: Channels 2-87 = 86 channels. 86 * 6 MHz. = 516 MHz.. 516 MHz. + 300 = 816 MHz..

You're looking for cable that has a frequency band-width (BW) of better than 850 Mhz.. It should specify it's been "frequency-swept" (tested for "flatness") from some low number like 5 MHz. up to, or better than 850 MHz.. This "flatness" just means that if a signal (say, at 10 MHz.) is injected into the cable at a reference level of +10dB., and the other end is measured and it measures at +7 dB., that cable shows a 3 dB. roll-off, or attenuation, for a 10 MHz. signal. Next, an 800 MHz. signal is injected. If the cable is good, it should show the same (reality is just a little more, but not too much) roll-off of around 4-5 dB.. If it's more than 6-10 dB., then that's the type of cable you want to stay away from.

Generally, the cable is marked on the box or cable reel it's in/on. But check with the manufacturer (Some cable manufacturer's websites are pretty good about giving you their cable's specs. in this area) to be sure that what you want to buy will do the job you're expecting it to perform.

Generally, I've been telling folks to get cable that's FS from 5 MHz. on the low end to up to, or better than 1 GHz. (1,000 MHz.). For most applications, this will work most nicely...

Now, I've heard that there is some cable that can go from 5 MHz. up to 2.4 Ghz.. If you run across that stuff, have at it...just be careful not to run a staple or nail through it...that's the ultimate DYIer "sucks" scenario...and Murphy lets that happen on the longest run, in the middle of said run and usually when the box/spool is about empty. Did I mention that the time is usually around 4:45 PM on a Friday afternoon? Yep, BTDT...

As for Brands? Belden - TimesFibre - CableWave - Each of these I've worked with in the past...Belden is the "gold" standard for what I do. You're paying for the name, but the quality has ALWAYS been there. TimesFibre and CableWave are what I've seen CCs use...they seem happy with their material so I wouldn't turn my nose up on those two brands.

As for the numbers? Check the websites...each application is different...just remember, you pay more for less attenuation (dB. loss per 100'/100m.) and the shielding that's just under the jacket of the cable.

RECOMMENDATION: Outdoor wiring? Get the best, low-loss, 100%-shielded cable you can afford...if you're burying it, make sure it's in heavy-duty conduit or it's the "flooded" type. Personally, I'd go the conduit route...the "flooded" is VERY MESSY and if you ever have to change it out or replace it, you'll have to dig everything up. Whereas, the conduit is there, protects the cable from Mother Nature's finest and helps facilitate replacement, if it should come to that.

Indoors? Again, quality over economy...at least for me...I go for 100% shielded cable and I route everything away from high-voltage sources (motors-pumps, etc...) as best as I can and I avoid sharp bends and turn-radius'. Stepping on, or kinking, the cable is the same as driving a staple or nail through it...keep the kids and high-heels out of the construction area and don't run over it yourself...you, yourself, can do as much, or more, damage as anything else. Watch what you're doing and again, practice save installation techniques.

Wooo! Sorry about the long-windedness here...

If you need anything else, PM me and I try to keep the reply a bit shorter...

jkoebel · #12 06-16-2008, 12:53 PM

Get yourself a powered distribution amplifier for your basement...they're less than a hundred and will regenerate your signal.

mgburg · #13 06-17-2008, 09:09 AM

Quote:

Originally Posted by jkoebel

Get yourself a powered distribution amplifier for your basement...they're less than a hundred and will regenerate your signal.

Not a good idea...

First: You're not fixing a problem...you may, in fact, be making it worse or even masking it so there's more time and energy involved in eventually fixing said item...

Second: The other sets downstream may not be able to handle that additional signal...some sets are sensitive enough that too much signal will damage the "front end" of the reciever. One heck of a way to find out it that's the case!

Third: A powered DA will always add some noise to your original signal...they all do...adding another link to any chain always increases the probablility of some type of failure by another 50% from before...use DAs (passive is better and powered, where possible) ONLY if there's a real need...don't use DAs to try to "FIX" a problem, use DAs to add additional sets, if needed...

This is a case of putting the cart before the horse...and the horse hasn't even been bought...