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Old 07-11-2007, 04:40 PM   #1
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Coaxial Cable Question


Hi everyone,

I've got a bit of a signal problem for my cable television in the house. I called the cable company and they came out to the house to take a look. From the street, they said that the signal quality was fine. They claimed that the problem was that the house is wired with RG59 cable. Their suggestion was that I should rerun it with RG6 cable, which they would be happy to do for me for an extra fee (which seemed pretty high to me).

A few things that may or may not be important about my house:
1 - There are three televisions in the house; 2 of them have cable boxes.
2 - There is also a high speed internet connection (which is cable based).
3 - I have VoIP phone in the house, so it runs over the internet connection, which is cable.
4 - Probably the longest run of cable is about 80 or 90 feet.
5 - The house is 23 years old, and the cable has probably never been replaced since the building of the house.
6 - The house has two stories - one of the hook ups is on the first floor, the other two are on the second.
7 - There are three splitters in the house: one on the outside of the house (not sure where the other two cables go, but one goes inside the house), one under the house (where the lines to the TVs and high speed internet connection go), and one from the wall (which splits the cable between the high speed internet connection and a television in a room).

So a few questions for you guys:
1 - Is there really a signal quality difference between RG6 and RG59?
2 - How hard would it be to run new cables? That is, take out the RG59 and put in the RG6. Ideally, I'd like to keep the lines running where the old ones are now. That is behind the walls.
3 - Any suggestions on how to actually run the lines? Especially the ones to the second floor?
4 - Outside of RG6 specification, is there anything special that I should be looking for when I buy the new cable?
5 - Would the splitters need to be upgraded as well or will they be able to handle the new cable? How about the wall jacks?

I know that was a really long post, thanks for getting through it! Thank you for any help that you can give me!

Phil

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Old 07-11-2007, 05:08 PM   #2
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Coaxial Cable Question


Quote:
Originally Posted by bahaisamurai View Post
1 - Is there really a signal quality difference between RG6 and RG59?
RG6 just has heavier shielding to resist interference, I would change the cable only after first checking your splitters, each split degrades the signal. Then maybe try a booster, Motorola has one for like $50 at any electronics store.

Quote:
Originally Posted by bahaisamurai View Post
2 - How hard would it be to run new cables? That is, take out the RG59 and put in the RG6. Ideally, I'd like to keep the lines running where the old ones are now. That is behind the walls.
Are they secured inside the wall? Otherwise just tape the old to the new and snake away. You may want to setup a central "AV center" and maybe even pull ethernet while you're at it for a home network? Or speaker wire for audio? I always try to think ahead when I'm rewiring...

Quote:
Originally Posted by bahaisamurai View Post
3 - Any suggestions on how to actually run the lines? Especially the ones to the second floor?
I thought you were just replacing the existing ones? Otherwise a snake will do the trick (and some patience)

Quote:
Originally Posted by bahaisamurai View Post
4 - Outside of RG6 specification, is there anything special that I should be looking for when I buy the new cable?
For your application I'd say no. Have you thought of upgrading to digital cable? You'll have to rent a box for each TV, but you'll have no quality loss

Quote:
Originally Posted by bahaisamurai View Post
5 - Would the splitters need to be upgraded as well or will they be able to handle the new cable? How about the wall jacks?
If they're old, replace them. Every connection degrades signal, every split causes a loss. It's a "weakest link" situation...

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Old 07-11-2007, 09:09 PM   #3
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Coaxial Cable Question


I'm going to beg to differ with part of the reply from Johnny331.

There is a HUGE difference between RG59 and RG6. Resistance values and bandwidth are but two of these differences.

That said:

It's hard to follow how the cabling is run by your description. I assume:

1. One splitter outside with one line going under the house and one line going up stairs?

2. A splitter under the house taking that one line from outside and sending it out to 2 0r 3 locations?

3. A splitter in the room where a TV and the VOIP/Modem is located?

If that's right:

You should be fine with the existing RG59.

What you will need is a bi-directional RF amplifier. I would say something like the Channel Vision CVT-2/8PIA II with a CVT-P1 power injector should be at the head end (cable demarc outside). This device would be your ONLY splitting device!

Note: Do not purchase a low end amplifier from Radio Shack, or some other outfit, it will not get the job done. And in all likelyhood will make matters worse.

Then ALL coax runs should be home run from this amplifier (NO splitters downstream from this point).

Meaning you should run run new cables under the house, eliminating that splitter. and you should run a new line in from outside to the VOIP/modem (although you may be workable without that last new run of coax).



I'm not all that surprised that the cable company is blaming the cable in your house. They're looking to drain you dry. That's what they do...

In my area, Time Warner will furnish an amplifier when needed (IF the customer complains enough). And in your case an amplifier is the fix.

I doubt that you'll need to worry about the second floor, even though there is probably a downstream splitter there as well.

If your signal strength from the street is within acceptable limits (FCC requires +7db at 7" from structure) the loses of all those splitters is what's doing you in, not the low grade coax.

Hope this helps....
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Old 07-11-2007, 11:07 PM   #4
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Coaxial Cable Question


Johnny and KT, thanks for the quick replies! Just a few points of clarification.

Johnny - If I am understanding your suggestion, you are thinking that I should first see if I can minimize the number of splitters, then if that still has a problem, I should consider upgrading to RG6. And your suggestion for wiring the RG6 is to pull the RG59 cable out of the wall a little, tape the end of the RG6 (electrical tape, maybe?) on to the end of the RG59, then go to the other end of the RG59 and gently pull it through, right? Makes sense.... (And while I'm at it, I could also pull some Ethernet cable through too. Again, great idea!) I've definitely got a few ideas from you. Thanks so much!

KTKelly - You seem to think that the RG6 would make a big difference, but for my little set up, might be a bit of an overkill, right? (Your three assumptions on the set up of my house were basically right...) However, that being said, you seem to think that I should also try to minimize the number of splitters. In looking at your suggestions, I think that I might already have what you were refering to. Outside of the house, I have the following:

On one of the TVs inside the house, I have the following (it goes only to one television):

I think that the first pic (which was in place when I bought the house) is what you described as the bi-directional RF amplifier, right? The second pic (which I actually got from Time Warner Cable) is what you warned me not to get, right?

So, if I am understanding you properly, I've got all of the hardware that I need, but probably just too many splitters. Does that sound about right?

Again, thank you two so much for your input. If anyone else wants to weigh in, please feel free.

PS - One last question, I promise. I ran into a similar problem about a year ago. Back then, Time Warner came out and gave me the hardware from the second picture listed above. Could there be anything else in the equation that would degrade the signal over a year? Thanks!
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Old 07-12-2007, 06:57 AM   #5
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Coaxial Cable Question


Phil,

The first pic is a bi-directional amplifier, and the second pic is a power injector. So the cable company gave you what you needed, at that time.


A problem I see there is that they installed a four port amplifier, with one port being used for the power injector, so there are only three outputs available for your use.


Now my questions are:

Are all ports on the amplifier in use?

Where exactly are the existing splitters? And are they 1x2 splitters?


Rest assured, the RG59 is not your problem. I'd bet that if your system worked after the cable company installed that amp, that you now have some build up on the various connectors and splitters. If you were to install new splitters and new ends on the cable lines, your problems would most likley go away. At least for some time....
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Old 07-12-2007, 09:11 AM   #6
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Coaxial Cable Question


I think you need special equipments to do the job right:

- measuring signal device
- making connector device

These are small devices, but you don't have them, you don't have them... those cheap equipment from HD cannot do the job ....

so you probably either spent a lot of $$ to get the good quality equipment to do the job yourself... or have no choice to pay someone to do it....

the cable core wire the thicker the better... (heard from my friend who work for cable company)...

the signal to internet should be from the line with strongest signal and do not split.... not any line can be used for internet....

tv lines is more forgiving....

I said if the cost is not sky high... you may be better off eat it and have it rest to the ground.... as your situation is complicated enough to justify the charge...
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Old 07-13-2007, 09:51 PM   #7
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Coaxial Cable Question


Quote:
Originally Posted by KUI****G View Post
I think you need special equipments to do the job right:

- measuring signal device
- making connector device

These are small devices, but you don't have them, you don't have them... those cheap equipment from HD cannot do the job ....
It's always best to have a good meter when designing a RF distirbution system, but even the average cable installer doesn't. You'll find that only the most senior techs from the cable company might have something like a Leader field strength meter.


That said, there is a way you can get a good idea of what you signal strength is. And that's the key to designing the system properly.

If you purchase several 1db attenuators (10 or so, they are cheap) you can use them to determine the starting signal strength.

1. Disconnect all but thincoming line at the demarc.
2. Connect a short jumper to a small TV at that location and check the picture quality.
3. Install attenuators one at a time, checking the picture quality after each is installed. When the picture quality becomes "snowy", you have found the starting signal strength (adding the number of attenuators).

So now you have the signal strength at the demarc. Let's say it's +7db.

1. A 1x4 "passive" splitter has a insertion (loss) of approximately 7db.
2. RG59 has a line loss of approximately 11db per 100' (the longest run).

You now know a 20db amplfier will give you a signal at +3db (roughly) at the end of the longest run.


Quote:
core wire the thicker the better... (heard from my friend who work for cable company)...
Actually it would be closer to say, the thicker the dialectric the better. But even that is sort of off the mark. Ask "friend if he uses CCS or CCA coax, percent of sheild and what the loss value is. I bet he might know the first, possibly even the second but will have no idea of the third.

Quote:
cable internet should be from the line with strongest signal and do not split.... not any line can be used for internet....

tv lines is more forgiving....
Not even close.....

Quote:
if the cost is not sky high... you may be better off eat it and have it rest to the ground.... as your situation is complicated enough to justify the charge...

Lost me on that one....



Yes, there are a large amount of variables that can come into play, but with this small system, it shouldn't be all that difficult to DIY.

If you do some research, you will find that the loss levels we (in the industry) use are the worst case numbers for OTA. Low channels (400mhz) will have less loss than much higher (900mhz) channels.

I do a LOT of RF distribution in my business....

My two rules?

1. No downstream splitters ever.

2. Equalize ALL input signals.

Rule #2 doesn't apply in this case.
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Old 07-15-2007, 09:51 PM   #8
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Coaxial Cable Question


Quote:
Originally Posted by ktkelly View Post
If you purchase several 1db attenuators (10 or so, they are cheap) you can use them to determine the starting signal strength.

1. Disconnect all but thincoming line at the demarc.
2. Connect a short jumper to a small TV at that location and check the picture quality.
3. Install attenuators one at a time, checking the picture quality after each is installed. When the picture quality becomes "snowy", you have found the starting signal strength (adding the number of attenuators).

So now you have the signal strength at the demarc. Let's say it's +7db.

1. A 1x4 "passive" splitter has a insertion (loss) of approximately 7db.
2. RG59 has a line loss of approximately 11db per 100' (the longest run).

You now know a 20db amplfier will give you a signal at +3db (roughly) at the end of the longest run.




Actually it would be closer to say, the thicker the dialectric the better. But even that is sort of off the mark. Ask "friend if he uses CCS or CCA coax, percent of sheild and what the loss value is. I bet he might know the first, possibly even the second but will have no idea of the third.
Wow. That bit was over my head. :-) However, I will take your advice below.

Quote:
Originally Posted by ktkelly View Post
My two rules?

1. No downstream splitters ever.

2. Equalize ALL input signals.
I'll definitely keep that one in mind.

Now, a few updates to my situation.
On Wednesday night, I took a look at the set up under the house and it looked like this:

A really big thick coax cable (RG 11?) came out of the ground and ran into a 1:2 splitter. That splitter went to the amp pictured above, and another line labeled "Dome 1" (I'm not actually sure where this goes, to the big box sitting out in front of the house I guess - I can track it down if need be).
From the Amp, there are 4 lines (one of course had power). Tracking them down, I saw that one went to the main living room (this is the one with the power, shown above), and it had a coax patched into another coax cable. The second line went to the master bedroom. The third line went to a 3:1 splitter and the fourth line went off somewhere that I didn't have time to track down. Also, I didn't have time to track the lines from the 3:1 splitter. (The only other piece of infrastructure that might be interesting is that I have a 2:1 splitter in my office - one end goes to the cable modem, the other to a TV (without a cable box).)

So, I took the patched cable out of the first line (to the main living room) and routed it directly to the TV. This really seemed to help with the reception in both the cable box in the main living room and the master bedroom.

So, I solved my problem and I really should have stopped there, but I was still getting some interference, So, I decided to press my luck, which I really shouldn't have. At this point, I went and replaced all of the face plates in the house (4 of them), and I cut the ends of the coax cabled connecting to the face plates and recrimped them with new F plugs (since I figured that the connections themselves might be dirty). Unfortunately, I'm back to the same place that I started. That is, both of the TVs with digital cable boxes are getting pixilated pictures, sound is dropping out and the image freezes sometimes.

So, here's a few more questions for you:
1 - Could the problem be that I crimped poorly? I looked at the wire and there's a good amount of room around the white inner cable and the hole in the F plug.
2 - When I went to the hardware store, I had the option of F plugs that crimped on and those that screwed on. I assumed that the ones that you crimp would be better, so I got those. Would it be better to try again with the screw on type?
3 - When the cable guy came out to the house, he showed me a way to see the signal strength on a cable box. He told me to look at channel 999. This is what it looks like:

The first circle is the strength of the signal and the second circle is what needs to be looked at to see how badly the pic is distorted. What is weird is that on Friday I left and numbers in the second circle were pretty high and there was a good deal of distortion. Over the weekend, I didn't use the TVs at all (except to record something on my DVR), and when I started up the TV today, it read 0/0/<# of seconds on>. The picture looked OK. However, after about 10 minutes, the problem came back and both of the first numbers were *really* high in the second circle (like it is in the picture). I'm including this pic just to see if there is any further information to be gleaned from it.
4 - What I am worried about is that some of the coax might have become frayed over the years (since I did see a frayed coax cable when I was recrimping the ends of the cable), so it might need replacing. So, here is what I am thinking. Please let me know if I am making any mistakes (IF, and that's a big IF, I need to rerun the cable in the house):
RG11 to the Amp
The Amp will have 4 outputs:
1 - To the main living room (with the power - no change from what it is now).
2 - To the master bedroom (no change from what it is now).
3- To the office (which would swap out the splitter that I currently have there).
4 - To the new splitter that I bought (just to replace the one that is currently down there and might be messed up).
The new splitter would have connections to each of the upstairs bedrooms (which is no change right now). (The thing about that is that 2 of the upstairs bedrooms have face plates which are not in use, though they are both currently hooked up.)
5 - While I was under the house, I noticed that there were 6 (unconnected) splitters under there. So, it looks like I am not the first person to trouble with the signal. I did buy an 8:1 splitter to replace it (though I didn't put it in yet). Since the new splitter that I bought has more connections than I need I would like to try to protect it from any dirt as much as possible. (It'll be under the house, so it'll be save from the elements, but there is a lot of dust and spiders crawling around down there, which might have been the problem with the other splitters. Is there any way to protect the unused connections? I was just going to user electrical tape over the unused connections in case I need to run them in the future. Will that mess it up? Is there a better way?
6 - My next question is my next course of action. I was planning on replacing the splitter and seeing if that helps, but I'm a little doubtful. After that my next thing would be replacing the existing coax - but I am really wary of doing that since it doesn't sound like an easy job. Any suggestions on what to do next if replacing the splitter doesn't work?

Again, thank you so much for your help! I'm really feeling more comfortable with this whole process and am hoping to drive this to completion very soon.

Thanks!
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Old 07-16-2007, 08:35 AM   #9
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"It's always best to have a good meter when designing a RF distirbution system, but even the average cable installer doesn't. You'll find that only the most senior techs from the cable company might have something like a Leader field strength meter."

not true... all the guys from cable company come with a small digital device which tells the signal... don't know if this is the top of the line euipment you are talking about... but somthing like that is a standard device cable guys carry around...


if the homeowner willing to go that far to tackle this issue... why not.... me... I found it so headache just to make a connector out of the troublesome coaxile cable... never made one I like so far... using the the cheap HD coaxile crimper.... not to mention to go through all these headache.... but you are right... if I don't have a friend in the industry... I probably also very reluctant to pay expensive $$ for someone to come over to fix it rather than trying it myself....

"Could the problem be that I crimped poorly?" Definitely... that is why you need the cable company equipment... it is not a rocket science equipment they have... but you just couldn't buy those with twenty thirty bucks.... may be hundred bucks....

Last edited by KUIPORNG; 07-16-2007 at 09:03 AM.
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Old 08-08-2007, 02:54 PM   #10
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I had some issue a while back with cable internet signal strength. The tech came out and ran some tests with his signal strength meter.

He showed me a real simple thing that a lot of people seem to miss. disconnect all your cable connections and look into the connector. The white insulation that is around the center copper wire should be flush with the bottom of the connector where the copper wire sticks through the hole.

He explained that this, like network cable, exposes the signal to outside interference and can seriously degrade your signal. Since this is so simple, I would check this first. It may save you a lot of time, money and effort.

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