# Another Coax question



## Scratch (Oct 6, 2007)

well being my first post on this BB, allow me to introduce myself. I am a wallpaper installer by trade (ask me any questions you want about that), but I do like doing the small jobs around the house if I can do it correctly without getting in over my head. Home is Norfolk MA, which is about a spud gun shot from Gillette Stadium. You can call me Scratch, Arch, or Bill. I'm an 11 year veteran of Internet newsgroup/listserv/BulletinBoard wars (seen a lot of action in them trenches, sonny :laughing: ) I have a bit of knowledge about vBulletin Boards as I am an admin on ngpp.org/lounge

Anyway on with the situation. I'm relocating my home office space, which means re-running the coax for TV and computer, and I want to do it as efficiently as possible. There will be one cable modem and three TV's (maybe more TV's in future and maybe HDTV in future)

1) what's a suitable amplifier/splitter for this ? And if I can not find EXACTLY what is recommended, what should I look for? 

2) I know in the "Coaxial Cable Question" thread KTKelly says "No downstream splitters". I understand this, I accept it. Is this an ABSOLUTE, or can one split be made to two TV's on one of those downsream lines? 

3)How long a run can I have AFTER the amplifier? 

4) how far from the present split Comcast installed for TV/Modem should an RF Amp go ?

I'm inferring from my research that compression connectors are superior to crimped connectors. True? From what I read the Thomas and Betts Snap n Seal are an industry standard. Is this true ? If this is a superior connector, is there any way of finding the tool (IT1000) cheaper than the $70 quoted? (Ebay was about the same after shipping) (I know the compression tool without stripper is a little cheaper, but if I'm spending THAT kind of money ......)

I think that covers it. I want to do this right so I won't need a Comcast tech coming out with a meter looking for my signal leak. So any other suggestions are welcome.


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## ktkelly (Apr 7, 2007)

Scratch said:


> Anyway on with the situation. I'm relocating my home office space, which means re-running the coax for TV and computer, and I want to do it as efficiently as possible. There will be one cable modem and three TV's (maybe more TV's in future and maybe HDTV in future)
> 
> 1) what's a suitable amplifier/splitter for this ? And if I can not find EXACTLY what is recommended, what should I look for?


Channel Vision CVT-2/4PIA11. Available all over the place.



> 2) I know in the "Coaxial Cable Question" thread KTKelly says "No downstream splitters". I understand this, I accept it. Is this an ABSOLUTE, or can one split be made to two TV's on one of those downsream lines?


Only if you want to do it right...:yes: 



> 3)How long a run can I have AFTER the amplifier?


This is something you'll probably not need to worry about...


> 4) How far from the present split Comcast installed for TV/Modem should an RF Amp go ?


You'll actually replace the Comcast splitter with the Channel Vison unit..



> I'm inferring from my research that compression connectors are superior to crimped connectors. True? From what I read the Thomas and Betts Snap n Seal are an industry standard. Is this true ? If this is a superior connector, is there any way of finding the tool (IT1000) cheaper than the $70 quoted? (Ebay was about the same after shipping) (I know the compression tool without stripper is a little cheaper, but if I'm spending THAT kind of money ......)


 
Thomas & Betts aren't really "the industry standard", but they are far superior to the average crimp connector. I personally use the Pro-Connect compression connectors. Same basic thing, just a slight bit of difference (I do RCA, RCA Mini, BNC, BNC Mini and F-connectors with mine).

If I were you I'd just go with the crimp connetors. Doing so few isn't worth the extra cost involved in buying the tool and connectors. Besides, maybe you can get the "cable guy" to put some on for you when you have them out next time....


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## /\/\arc (Oct 5, 2007)

Scratch -- depending on your cable company, they may provide and install the cable amplifier for you. 

I was having trouble with my digital cable picking up certain channels and the tech installed an amp for me at no charge. It also helped out my cable internet connection.


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## jscholl411 (May 8, 2006)

scratch, First of all how many tv's presently do you have coming off of you cable? How far are you moving the tv and internet? do you or can you make a picture or drawing? A basic rule is the 5 or more out puts might need an amp. My house has 6 tv with one being HD. I have no Amps and the signal is perfectly clear. Basically Just take the setup that you have now and move it down the line to where you want it. You can use a splitter on the internet. Look at a splitter and it has 7.5 mhz and 3.5 mhz. Use the internet on the 3.5. and the rest of the tv's on the others.


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## KUIPORNG (Jan 11, 2006)

Internet connection should not be splitted to avoid signal weakening

HDTV may be able to split once ....guessing...

Traditional TV signal you can split almost as much as you want without lossing noticable signal...of course.. not talking about split 10 times... a few times is ok....

you may not need the sophisticated amplifier if you can arrange things properly... more importantly is how you make the connection and what quality of cable you are using and quality of the spliters... you don't find good quality of those stuff from HD for example....


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## Scratch (Oct 6, 2007)

Thanks all,

Each day my thoughts for configuring this changes, so no diagram will be drawn :whistling2: 

Final amount of TV's will be 4.

I am trying to figure out configuration so that Internet goes off original split, which may be a four way split. 
Internet - TV 1 - TV 2 - TV 3 
TV 4 will be split off from one of the other TV's. 

I'm trying to work on a solution that will have least length of cable. 

But thanks, you've given me food for thought.


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## jscholl411 (May 8, 2006)

Scratch,
I believe the in your situation the cable length is not a problem. How far away are your tvs and internet now from the main splitter? The one good thing about cable is that the length should not really kill the signal. its the amount of eqpt that you have on the lines. each time you put a break in the line you distort the quality of the signal. Basically for having 4 televisions and an internet. From the home run to the house I would get a 3 way splitter, have the internet go off the 3.5 db output, and have the HD tv go off of one of the other outputs. That the internet and hd out of the way, now 3 tvs left. Get a piece of coax and another 3 way splitter. run the other three tv's off the 1st splitter. here are pictures of what im
talking about.


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## ktkelly (Apr 7, 2007)

jscholl411 said:


> Scratch,
> I believe the in your situation the cable length is not a problem. How far away are your tvs and internet now from the main splitter? The one good thing about cable is that the length should not really kill the signal. its the amount of eqpt that you have on the lines. each time you put a break in the line you distort the quality of the signal. Basically for having 4 televisions and an internet. From the home run to the house I would get a 3 way splitter, have the internet go off the 3.5 db output, and have the HD tv go off of one of the other outputs. That the internet and hd out of the way, now 3 tvs left. Get a piece of coax and another 3 way splitter. run the other three tv's off the 1st splitter. here are pictures of what im
> talking about.


 
Both of these layouts are incorrect....

Will they work? Maybe yes, maybe not....

Will they be right? No way....


Once again, you *DO NOT* place splitters downstream. There is *NO* way you can *properly* engineer a system when splitters are downstream.



To the OP:

Do yourself a favor, do it right, and home run each and every coax back to the demarc.


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## jscholl411 (May 8, 2006)

So basically you would have a 5 or 6 way splitter off the home run? Both of these are not incorrect, One is really not the way to go but would work and the other is basically the way to go.


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## ktkelly (Apr 7, 2007)

Sorry...


*BOTH *are incorrect. One pictures a 3 way splitter followed by another 3 way splitter, and the other pictures a 2 way splitter followed by a 4 way splitter.


Doesn't anyone really understand what *"no splitters downstream"* mean?


The bottom line is that there is no way to *properly* balance the system with a design as pictured.



FWIW: I do these systems on a professional level.....


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## jscholl411 (May 8, 2006)

Ok, I dont want to get into a pissing match with any one. How would you do it then? I also do this type of work and would love to learn something new? I know you said to home run everything back to the dmarc. But how are you going to get the signal out to the eqpt without splitters?


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## ktkelly (Apr 7, 2007)

The way it *should* be done in a typical residential application....

One bi-directional amplified splitter at the demarc (or structured wiring enclosure), or one bi-directional amplifier immediately prior to a passive splitter in either location.


Were you cabling an MDU the design would be different. In that case you would normally be using "taps" (not splitters) for each unit. But commercial is a completely different animal.


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## jscholl411 (May 8, 2006)

I would agree with that. Here I have only place in a couple amplified splitter, The only time i have is when the signal level is to low at the dmarc. Here, basically the cable comes from the pole to the side of the house to a grounding block. From the grounding block it is brought into the home. once in the home the cable is split down accordingly. Internet (no filters ) HDTV, SDTV. If the amount of equpt is 5 or more the a amplifier is places where the cable comes into the home. This is the way it is done where I live. It must not be the same where you are. But thats cool, I learned something new today. I have done it like that before but didnt know it was a standing practice.


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## ktkelly (Apr 7, 2007)

jscholl411 said:


> I would agree with that. Here I have only place in a couple amplified splitter, The only time i have is when the signal level is to low at the dmarc. Here, basically the cable comes from the pole to the side of the house to a grounding block. From the grounding block it is brought into the home. once in the home the cable is split down accordingly. Internet (no filters ) HDTV, SDTV. If the amount of equpt is 5 or more the a amplifier is places where the cable comes into the home. This is the way it is done where I live. It must not be the same where you are. But thats cool, I learned something new today. I have done it like that before but didnt know it was a standing practice.


 
Well, if you are in the USA, the standard is ALL coax runs are to be homerun. And FCC regulations require the signal strength to be a minimum of 7db (millivolts) measured at 6" from the structure (which is the demarc).

Typically that 7db will be sufficient for most residential applications. Most.. 



Average insertion loses for the variety of splitters:

1x2 low = 3.5, high = 5.0
1x3 low = 6.0, high = 9.0
1x4 low = 7.5, high = 9.5

RG6 Coax loss is average 6db per 100'


Using that info you can reasoably estimate the required amplification knowing that internet service will, somewhat, function at -7db.

Demarc signal strength less splitter loss, less line loss (longest run) will give you the signal strength at the most remote location.

7db - 9.50db - 6.0db = negative 10.50 db. Use amp with 10db gain and you should be fine.


Over 150' coax runs may need tilt compensation. Shortest runs may need attenuation.

And FWIW;

The only way to be 100% on the money is to use a field strength meter...:yes:


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