CATV
- Thread starter rrrusty
- Start date
- Status
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: CATV
Rusty
To determine how many splitters can be used would require a person to know how much signal is coming into a house.
Each splitter has a loss of about 3db when you daisy chaining splitters the loss can be quit substantial and will result in undesired video quality when you split all the cables at one splitter you still only loose 3db but since it is only once this will be the only loss. after going through 3 splitters the loss will be 9db this would be very hard to make back up without amplifier noise.
Second is that most newer digital signals wont pass through these splitters and would require the running of new cable to be able to have digital TV.
third is if you ever want satellite TV again it wont go through splitters. so running cable in this way is the worst way one could do it as it limits the end result and should not be done especially if your doing it for a customer. as this customer could comeback later and ask for his money back as it would clearly show incompetence as a cable installer.
The best way, and the way most cable companies require the cable to be installed is to run each run to a location close by the main service (so it can be properly bonded) you can drop them out of a wall by the panel and run a short feed to the outside for cable hookup but we just drop them to the outside and the cable company will hook up the rooms that will have a TV connected.
the other thing that this allows is that it also gives you the ability to run a feed from this point to the attic and or to a place where a satellite dish might be located. then the home owner has the best of all worlds. but if a satellite is in the future then it is best to make two runs to each cable outlet so there can be alternative hook of an out side ant or cable for local channels.
another good thing to do is include a cat5 cable to each cable jack to allow for the satellite or digital cable box which requires a phone connection for view on demand pay per view.
One last thing is you have to keep in mind that cable TV uses all of the radio spectrum this means if the cable is not installed properly and is allow to leak out into the open air it will affect everyone that uses two-way radios to communicate. and the cable company and the home owner could be fined. had a neighbor who had to pay $2000 fine for this and the cable company got hit with $10,000 fine this was mostly because we are in a landing pattern for O'Hara airport. and they couldn't hear the tower. cable channel 19 is dead in the middle of the police frequency band and will disrupt them so be careful that the shields are in place and you don't leave any uncapped jacks
Rusty
To determine how many splitters can be used would require a person to know how much signal is coming into a house.
Each splitter has a loss of about 3db when you daisy chaining splitters the loss can be quit substantial and will result in undesired video quality when you split all the cables at one splitter you still only loose 3db but since it is only once this will be the only loss. after going through 3 splitters the loss will be 9db this would be very hard to make back up without amplifier noise.
Second is that most newer digital signals wont pass through these splitters and would require the running of new cable to be able to have digital TV.
third is if you ever want satellite TV again it wont go through splitters. so running cable in this way is the worst way one could do it as it limits the end result and should not be done especially if your doing it for a customer. as this customer could comeback later and ask for his money back as it would clearly show incompetence as a cable installer.
The best way, and the way most cable companies require the cable to be installed is to run each run to a location close by the main service (so it can be properly bonded) you can drop them out of a wall by the panel and run a short feed to the outside for cable hookup but we just drop them to the outside and the cable company will hook up the rooms that will have a TV connected.
the other thing that this allows is that it also gives you the ability to run a feed from this point to the attic and or to a place where a satellite dish might be located. then the home owner has the best of all worlds. but if a satellite is in the future then it is best to make two runs to each cable outlet so there can be alternative hook of an out side ant or cable for local channels.
another good thing to do is include a cat5 cable to each cable jack to allow for the satellite or digital cable box which requires a phone connection for view on demand pay per view.
One last thing is you have to keep in mind that cable TV uses all of the radio spectrum this means if the cable is not installed properly and is allow to leak out into the open air it will affect everyone that uses two-way radios to communicate. and the cable company and the home owner could be fined. had a neighbor who had to pay $2000 fine for this and the cable company got hit with $10,000 fine this was mostly because we are in a landing pattern for O'Hara airport. and they couldn't hear the tower. cable channel 19 is dead in the middle of the police frequency band and will disrupt them so be careful that the shields are in place and you don't leave any uncapped jacks
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: CATV
As a rule of thumb there should be enough signal to split the drop four ways with a minimum level of 0db at the set. As a former cable company engineer I always designed for +6 to +10db at the highest frequency at the tap on the street. Unfortunately long drops and poorly maintained systems can make the actual level at your house less than what is necessary to split the drop even four ways.
If you expect to supply 11 home runs there is no question that (unless your drop is unusually hot) you will need an amplifier. Without measuring the actual levels at the side of your house you are going to need 12db of gain just to break even after all those splitters.
Incidentally, rather than cascading those six ways one after the other like you did, use a two way to feed each six way. This will reduce the loss by 3db. Keep in mind also that those six ways should have two ports on each that are hotter than the rest by 3db. Use them to feed the longest runs. Make sure that those splitters are good for at least 1Ghz (1000Mhz) also.
Best advice I can give you is to give your cable company a call to see what they recommend. Most will supply a home run amplifier at minimal cost. Many systems are 2 way which means that in addition to the downstream signal, an upstream signal is sent from the addressable cable boxes back to the head end. If you don't use the proper amplifier that will pass signals in the reverse direction your boxes may not work or some features may not work.
As a rule of thumb there should be enough signal to split the drop four ways with a minimum level of 0db at the set. As a former cable company engineer I always designed for +6 to +10db at the highest frequency at the tap on the street. Unfortunately long drops and poorly maintained systems can make the actual level at your house less than what is necessary to split the drop even four ways.
If you expect to supply 11 home runs there is no question that (unless your drop is unusually hot) you will need an amplifier. Without measuring the actual levels at the side of your house you are going to need 12db of gain just to break even after all those splitters.
Incidentally, rather than cascading those six ways one after the other like you did, use a two way to feed each six way. This will reduce the loss by 3db. Keep in mind also that those six ways should have two ports on each that are hotter than the rest by 3db. Use them to feed the longest runs. Make sure that those splitters are good for at least 1Ghz (1000Mhz) also.
Best advice I can give you is to give your cable company a call to see what they recommend. Most will supply a home run amplifier at minimal cost. Many systems are 2 way which means that in addition to the downstream signal, an upstream signal is sent from the addressable cable boxes back to the head end. If you don't use the proper amplifier that will pass signals in the reverse direction your boxes may not work or some features may not work.
jrdsg
Senior Member
- Location
- Vancouver, Canada
Re: CATV
for help laying out this stuff check out www.onqtech.com. channel vision and channel plus are also good sources for layout info.
be sure to terminate any unused outlets either on the splitters at the head end or at the outlets with 75 ohm resistor caps to avoid radiating the neighborhoor and further attenuating your signal at the drops you are using.
use quad-shield rg6 cable and crimp-on f connectors. make sure the f connectors are installed per manufacturer's instructions. look for a crimping tool/end combo that yields a conical crimp around the base of the connector. ensure that the dielectric foam insulation around the center conductor of the rg6 protrudes a little into the connector so that it can seal up against the bulkhead connector.
satellite systems require more frequency headroom. look for 1.5-2Ghz rated splitters and amplifiers. some systems require bidirectional amplifiers while others are fine with one-way amps. buy good quality amps, connectors, splitters, etc. from a pro supplier [not RS].
for help laying out this stuff check out www.onqtech.com. channel vision and channel plus are also good sources for layout info.
be sure to terminate any unused outlets either on the splitters at the head end or at the outlets with 75 ohm resistor caps to avoid radiating the neighborhoor and further attenuating your signal at the drops you are using.
use quad-shield rg6 cable and crimp-on f connectors. make sure the f connectors are installed per manufacturer's instructions. look for a crimping tool/end combo that yields a conical crimp around the base of the connector. ensure that the dielectric foam insulation around the center conductor of the rg6 protrudes a little into the connector so that it can seal up against the bulkhead connector.
satellite systems require more frequency headroom. look for 1.5-2Ghz rated splitters and amplifiers. some systems require bidirectional amplifiers while others are fine with one-way amps. buy good quality amps, connectors, splitters, etc. from a pro supplier [not RS].
Re: CATV
Got it fine tunned! I put the booster so the feed from the street is at the input and put 1-3way splitter to feed 3 splitters in line so the signal is only hampered by the main splitter; I had to go and find all of the splitters this guy had in his existing system and remove them so all of the tv's went to one central location; Thank you guys
Got it fine tunned! I put the booster so the feed from the street is at the input and put 1-3way splitter to feed 3 splitters in line so the signal is only hampered by the main splitter; I had to go and find all of the splitters this guy had in his existing system and remove them so all of the tv's went to one central location; Thank you guys
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