I am wondering why the industry uses 2 different types of splitters for CATV applications. Specifically, 3db & 7db splitters in the 5 to 1000Mhz range. Does this have to do with Digital verus analog station delivery? How does this affect Internet delivery on the same circuit?
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CATV coaxial cables and splitters 2
- Thread starter 1Drisnil
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- #2
Servamatic
IS-IT--Management
Generally speaking the dB difference comes from the number of splits.
A typical 2 way splitter will have 3dB loss, an unbalanced 3 way will have 2 legs at a 3dB loss and 1 at 7dB loss, a 4 way will have all legs at 7dB loss...and so on..
The better balanced splitters will have equal loss on all legs.
My personal opinion spend the money for good splitters, and if you split 6 ways or more, Amplify.
Several manufacturers make Unity gain (a net zero loss) splitter/amplifiers, such as Leviton's 3x8 which has adjustable amplification. -5dB to + 15dB
Richard S. Anderson, RCDD
A typical 2 way splitter will have 3dB loss, an unbalanced 3 way will have 2 legs at a 3dB loss and 1 at 7dB loss, a 4 way will have all legs at 7dB loss...and so on..
The better balanced splitters will have equal loss on all legs.
My personal opinion spend the money for good splitters, and if you split 6 ways or more, Amplify.
Several manufacturers make Unity gain (a net zero loss) splitter/amplifiers, such as Leviton's 3x8 which has adjustable amplification. -5dB to + 15dB
Richard S. Anderson, RCDD
- Thread starter
- #3
Thanks, Servamatic!
I see now, the decibels are a measure of signal loss due to splitting. Unequal splits cause unequal signal loss. Its been a while since I had a Discrete engineering signal class, and I do not use this material in my professional life.
He's my grief, at home we have a 3 way split and lastter down the run on one leg a 2-way split. So, for easy of understanding, the first 3-way split I will call A,B,C. A & C are 7db and B is 3db. The second 2-way split I will call D & E and both are 3db.
All but 1 split are in use, should I disconnect that run not in use to lessen the signal loss?
The run with the 7db signal loss, is that worse in terms of picture quality?
I see now, the decibels are a measure of signal loss due to splitting. Unequal splits cause unequal signal loss. Its been a while since I had a Discrete engineering signal class, and I do not use this material in my professional life.
He's my grief, at home we have a 3 way split and lastter down the run on one leg a 2-way split. So, for easy of understanding, the first 3-way split I will call A,B,C. A & C are 7db and B is 3db. The second 2-way split I will call D & E and both are 3db.
All but 1 split are in use, should I disconnect that run not in use to lessen the signal loss?
The run with the 7db signal loss, is that worse in terms of picture quality?
- Thread starter
- #4
Follow-up questions,
So Comcast came out to the house on Saturday only to say he couldn't resolve the issue. Of the problem found, he said 3 are correctable, 2 for a fee. He said this:
1) fixable free of charge - signal level at the street is very low -- seperate division will resolve it .
2) Need different cable run in the house. Apparently the house uses R-59 and the cable now used is R-6.
3) The length limit to the R-6 cable is 150 feet. All the connections are on the wrong side of the house form the demarc. Apparently the cable runs 75% around the house just to get to the 1st splitter, then runs 75% back around the house to get to the internal jacks.
My question is, how much of what was stated is valid? How much do you think the resolution should cost? Could I rewire this myself? How much would it cost me if I were to do it myself?
So Comcast came out to the house on Saturday only to say he couldn't resolve the issue. Of the problem found, he said 3 are correctable, 2 for a fee. He said this:
1) fixable free of charge - signal level at the street is very low -- seperate division will resolve it .
2) Need different cable run in the house. Apparently the house uses R-59 and the cable now used is R-6.
3) The length limit to the R-6 cable is 150 feet. All the connections are on the wrong side of the house form the demarc. Apparently the cable runs 75% around the house just to get to the 1st splitter, then runs 75% back around the house to get to the internal jacks.
My question is, how much of what was stated is valid? How much do you think the resolution should cost? Could I rewire this myself? How much would it cost me if I were to do it myself?
Servamatic
IS-IT--Management
Morpth
What he told you is correct. RG-59 does have a higher loss rate than RG-6, especially when the lines get longer.
So it would be a benefit to upgrade to RG-6, if you do so run it in the crawl space or attic to shorten the runs as well.
This would allow you to rid your system of some of the splitters as well hopefully.
Also, any unused connections that are connected to the source need to have a 75 Ohm terminator on them. An open port on coax does act like a leaky faucet so to speak.
You should be able to by 75 Ohm coax terminator caps at Radio Shack, possibly Home Depot.
RG-6 will cost around 65.00/1000’ Buy quality compression type connectors NOT crimp style, probably around .45 each.
Hope this helps, if you have questions I would be happy to help, so ask away.
Richard S. Anderson, RCDD
What he told you is correct. RG-59 does have a higher loss rate than RG-6, especially when the lines get longer.
So it would be a benefit to upgrade to RG-6, if you do so run it in the crawl space or attic to shorten the runs as well.
This would allow you to rid your system of some of the splitters as well hopefully.
Also, any unused connections that are connected to the source need to have a 75 Ohm terminator on them. An open port on coax does act like a leaky faucet so to speak.
You should be able to by 75 Ohm coax terminator caps at Radio Shack, possibly Home Depot.
RG-6 will cost around 65.00/1000’ Buy quality compression type connectors NOT crimp style, probably around .45 each.
Hope this helps, if you have questions I would be happy to help, so ask away.
Richard S. Anderson, RCDD
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