[smikhailov]


I have one coax cable (and one cat6 cable, if this makes a difference) that runs from a utility closet to the outside. The utility closet also has coax/cat6 running to all the bedrooms, so I can multiplex signal to whichever bedroom I need. I now wonder if having just one coax going to the outside is sufficient since I want 1) a roof antenna and 2) comcast internet connection. With just one coax, my only option is to have the roof antenna coax and the comcast coax from the utility pole connect into one coax coming into the house. Will this work? Will the comcast signal and the roof antenna signal get "mixed up" as they go through one coax that comes into the house? My goal is to be able to have a hard-wired LAN connection to each bedroom and should there be TVs in bedrooms I want them to be able to tune the over the air channels from the roof antenna. I don't want to pay for comcast cable, in which case I know one coax to outside is enough. Sorry if this is an obvious question and thanks for all the help.

 

[trans_lux]

I think I understand what you are trying to do.


Basic idea

You will need a combiner-also referred to as a diplexer- to combine the signals and then a splitter to break them out.

eBay has an article that goes into more detail
http://www.ebay.com/gds/The-Basics-of-Using-TV-Signal-Splitters-and-Combiners-/10000000177630742/g.html


These are the kind of devices you will need. I know they list them for Sat use but they will work for your application.

I'd email them and see what they suggest.
http://prosatellitesupply.com/diplexer.html

 

[commsysman]

You should keep the cable for the roof antenna completely separate to avoid problems.


You should also be aware that distributing (splitting) the signal to several locations divides up and weakens the signal to each location.


I suggest that you connect the antenna signal to a distribution amplifier, which will boost the signal strength and have several outputs to go to the various locations in the house (for example Channel Master 3414).

 

[dstoffa]



Quote:
Originally Posted by smikhailov  /t/1523441/can-i-use-one-coax-cable-for-both-comcast-internet-and-roof-antenna-signal#post_24506645


I have one coax cable (and one cat6 cable, if this makes a difference) that runs from a utility closet to the outside. The utility closet also has coax/cat6 running to all the bedrooms, so I can multiplex signal to whichever bedroom I need. I now wonder if having just one coax going to the outside is sufficient since I want 1) a roof antenna and 2) comcast internet connection. With just one coax, my only option is to have the roof antenna coax and the comcast coax from the utility pole connect into one coax coming into the house. Will this work? Will the comcast signal and the roof antenna signal get "mixed up" as they go through one coax that comes into the house? My goal is to be able to have a hard-wired LAN connection to each bedroom and should there be TVs in bedrooms I want them to be able to tune the over the air channels from the roof antenna. I don't want to pay for comcast cable, in which case I know one coax to outside is enough. Sorry if this is an obvious question and thanks for all the help.

See this thread...

http://www.avsforum.com/t/1438808/connecting-tv-antenna-coaxial-cable-to-existing-cable-box-outisde-my-home


You really can't use one coax for cableTV (whether it be internet or video) and OTA.


Any what does the cat6 cable that runs outside connect to? Where is your cable modem?



Cheers!

-=Doug

 

[Ratman]

Cable coax should go directly to cable modem in the closet for internet.

Run new coax from antenna to distribution panel in the closet for OTA/TV.


Add a switch/router to the cable modem. Use the Cat6 for ethernet to the desired locations as needed.

Add splitters or distribution to send antenna/TV to desired locations over existing coax.

 

[trans_lux]

You can absolutely run digital cable and OTA over the same cable with no perceptible loss. We have done this for years. You are correct you may need an amp.

And you can split the incoming cable signal many times before the modem with no loss in performance.

We have tested this extensively in many different environments.

The only caveat to this is you must you high quality cables, connectors-compression fit only, that are terminated correctly-splitters/combiners and amplifiers.

I'd give the sat guys I linked you to or someone like them a shout and they will help you sort out a functional solution.

 

[ctdish]

trans_lux not really. You might get lucky and find a location where it seems to work. You might even design it to work if you had knowledge of the frequencies of the digital channels desired from cable and the antenna using expensive filters for each channel from each source. More likely neither cable nor the over the air signals will work. You could also be subject to FCC fines. See post 9 of dstoffa's referenced thread.

John

 

[Ratman]



Quote:
Originally Posted by trans_lux  /t/1523441/can-i-use-one-coax-cable-for-both-comcast-internet-and-roof-antenna-signal#post_24507359


You can absolutely run digital cable and OTA over the same cable with no perceptible loss. We have done this for years. You are correct you may need an amp.

And you can split the incoming cable signal many times before the modem with no loss in performance.

We have tested this extensively in many different environments.

The only caveat to this is you must you high quality cables, connectors-compression fit only, that are terminated correctly-splitters/combiners and amplifiers.

I'd give the sat guys I linked you to or someone like them a shout and they will help you sort out a functional solution.

Ouch! Hopefully the OP doesn't have to find out the hard way.

Separate "cable" from "OTA". That's the best option.

 

[Otto Pylot]

+1

 

[trans_lux]

Your right my bad. Don't use a single cable. If you end up back feeding you could have some serious issues.

I'm familiar with combining Sat & Ota and assumed it would work with dig cable.

I forgot my own manta "just because you can doesn't mean you should"

I agree a separate cable is certainly the best.

 

[Ratman]



Quote:
Originally Posted by trans_lux  /t/1523441/can-i-use-one-coax-cable-for-both-comcast-internet-and-roof-antenna-signal#post_24509073


I'm familiar with combining Sat & Ota and assumed it would work with dig cable.

You should know what happens when one "assumes".

 

[egnlsn]



Quote:
Originally Posted by trans_lux  /t/1523441/can-i-use-one-coax-cable-for-both-comcast-internet-and-roof-antenna-signal#post_24507359


You can absolutely run digital cable and OTA over the same cable with no perceptible loss. We have done this for years. You are correct you may need an amp.

And you can split the incoming cable signal many times before the modem with no loss in performance.

We have tested this extensively in many different environments.

The only caveat to this is you must you high quality cables, connectors-compression fit only, that are terminated correctly-splitters/combiners and amplifiers.

I'd give the sat guys I linked you to or someone like them a shout and they will help you sort out a functional solution.

Diplexing satellite with OTA is not the same as diplexing digital cable and OTA.


Satellite I.F. is at 950-1450MHz while broadcast was 54-216MHz for VHF and 470-890MHz for UHF. Then UHF got dropped to 806, and now 698MHz, while VHF stayed the same.


The bandwidth of digital cable (includes internet) is continuous from 300-1002MHz. Broadcast UHF is right there in the middle of it. While, as John wrote, you may be able to make it work utilizing expensive filters (you'd also need filtering for the return path of 5-42MHz, which is where the cable modem transmits), you don't know if/when the cable company will shuffle things around and your internet will be right there in your local CBS station. In my area, that would wipe out my ABC, NBC, and one of my PBS stations.

 

[Cableguy Greg]


If one combines the OTA with the cable service, it will inject massive amounts of noise in the cable system. The return path on the cable will be filled with OTA noise and more than likely it will shut down the fiber node for the neighborhood. When that happens, the cable company will shut off the service to the house that is causing the issue. Being the guy that has to find these issues, usually at 3AM, we are not fond of mixing OTA with cable service. I am sure that it can be done, but you need a lot of expensive filters like the others have stated above.

 

[holl_ands]

FINAL NAIL IN THE COFFIN (Body Blow to the originator's intended purpose):


CATV occupies nearly EVERY Frequency from below 54 MHz (for Reverse Channel back to Local Node) to AT LEAST 860 MHz (usually, and some systems go up to 1002 MHz and MOCA Whole-Home Networks are ABOVE that).


CATV signals are VERY STRONG and will SWAMP whatever weak OTA signal might be present due to using an RF Combiner.

SO OTA HAS NO CHANCE OF WORKING!!!

 

[Ratman]

No new news. You can't combine and/or diplex OTA and cable due to shared\overlapping channel frequencies. It's been discussed for over a decade since I've been here at AVS.

No "body blow" or "nail in the coffin" necessary.

And FWIW, the OP hasn't been back since the original post.