How to hook up both cable & Direct TV, same house?

[eapeas]

First off, hello fellas! I've just come over from avsforum and from the tivocommunity. Thought this would be the best place to post this, but if not, please feel free to direct me to the right forum...

I am about to make the switch to Direct TV (D*) from cable, sort of. I have what I consider a unique situation, but maybe not. Imagine a house with a "front" and "back" half. The front half will get cable tv only. The back half will get D* only, but will also need one cable for my cable modem and my high-speed internet.

I have ZERO idea as to how to set this up or what to tell the D* installers when they come. Can anyone give me an "Idiot's Guide" as to what I need to do and how to do it? Many many thanks and I hope to become an active member here.

Oh, one other thing...as I live in West Texas, D* does not offer my local channels. This is not really a huge issue to me, but I am wondering...can I get, say, Dallas's locals, as I don't want to be w/o ABC, CBS, FOX, etc.

Thanks again and glad to be here!:up

 

[mastermesh]

Just let the guys install and tell them which main rooms you want installed to... once they leave, go to wal-mart and buy a few hundred feet of coax, and do the rest of the wiring yourself... it'll probably be more the way you want it and cheaper... basically you just use y splitters and keep using them to get to whatever tvs/computers you need to get to... shucks, if you really want to go all out, install a tv in/out card in computer too - like an ati all in wonder, so modem gets it's internet feed and the graphics card can see the cable channels and will work like a pvr for ya. All in wonders work fabulously with cable!

 

[Jared Twomey]

just make sure to tell the installer up front that you are keeping cable in some of the rooms and for your internet, that way they know not to start unhooking things.

 

[KE4EST]

eapeas I would like to welcome you to SatelliteGuys.

 

[Todd Humphrey]

Forget doing any wiring yourself. If you knew how to properly select your coax and do it yourself, you would not be asking how here.
Birddoggy had right. Show the installers the rooms need to keep on CATV for TV and Internet and let them figure it out. That is thier job.

You CANNOT run satellite and cable tv or Internet on the same line. I do not care if someone says you can, you cannot.

If this looks like it might get sort of complicated, offer to tip well before they start. You will be amazed at how much more an installer will do for you if he knows you will show your appreciation with a $20 bill at the end.

 

[HCI]

You CANNOT run satellite and cable tv or Internet on the same line. I do not care if someone says you can, you cannot.

You are misinformed. You can and I have plenty of times with a couple of diaplexers.

 

[stevo/65]

If this looks like it might get sort of complicated, offer to tip well before they start. You will be amazed at how much more an installer will do for you if he knows you will show your appreciation with a $20 bill at the end.

Depending on how many $ 20 bills at the end

You CANNOT run satellite and cable tv or Internet on the same line. I do not care if someone says you can, you cannot.

You can with diplexors

 

[rcdallas]

Cable modem's _might_ work with diplexers on a sat line, the problem is the two bands are too close to each other, it may work fine for awhile, but it could interfere with each other at some point.

My guess is, each cable company's system is different. For example in my area where I am serviced by charter, they use 0-1000 MHz. This is what I was told by the Charter guy that installed my internet service. When I was working Comcast, the system ranged from 0-900 MHz, thus giving you a 50MHz seperation, depending on how strong the signal levels are, harmonics, localized RF emissions, etc, etc, it may work flawlessly for years, then again it maybe a problem.

Any Dish Network geek knows that Legacy equipment uses 950-1450 MHz, and Dish Pro/Dish Pro Plus uses 950-2150MHz. I have no idea what DirecTV uses frequency range wise, so I could not comment on that.

Sure you can combine signals at this point and share the same line, provided you have a channel that is not in use by the cable carrier.

As in my setup, I combined TV2 output on CH80 on my cable line to feed my 2nd television.

All in all, unless you know what frequency range is in use by your cable carrier, and there is enough spacing between on the sat line, depending on exactly how you want to configure it, DONT diplex sat lines and cable modem's on the same line.

Or if you really know what your doing, and you know the systems, you could probably get some traps from the cable co, place them strategicly based on the layout of the install and do some crazy things that'll make the next guy scratch his head on a service call.

Simply put, I'd probably just run new lines for Direct on the back half, and new lines for cable on the front half, keep it simple.

 

[stevo/65]

Cable modem's _might_ work with diplexers on a sat line, the problem is the two bands are too close to each other, it may work fine for awhile, but it could interfere with each other at some point.

My guess is, each cable company's system is different. For example in my area where I am serviced by charter, they use 0-1000 MHz. This is what I was told by the Charter guy that installed my internet service. When I was working Comcast, the system ranged from 0-900 MHz, thus giving you a 50MHz seperation, depending on how strong the signal levels are, harmonics, localized RF emissions, etc, etc, it may work flawlessly for years, then again it maybe a problem.

Any Dish Network geek knows that Legacy equipment uses 950-1450 MHz, and Dish Pro/Dish Pro Plus uses 950-2150MHz. I have no idea what DirecTV uses frequency range wise, so I could not comment on that.

Sure you can combine signals at this point and share the same line, provided you have a channel that is not in use by the cable carrier.

As in my setup, I combined TV2 output on CH80 on my cable line to feed my 2nd television.

All in all, unless you know what frequency range is in use by your cable carrier, and there is enough spacing between on the sat line, depending on exactly how you want to configure it, DONT diplex sat lines and cable modem's on the same line.

Or if you really know what your doing, and you know the systems, you could probably get some traps from the cable co, place them strategicly based on the layout of the install and do some crazy things that'll make the next guy scratch his head on a service call.

Simply put, I'd probably just run new lines for Direct on the back half, and new lines for cable on the front half, keep it simple.

I am very famaliar with the cable side of forward and reverse streams and what the frequency range is for the average cable system which is usually 5-950 mhz,
If you are using Directv or dishnet the frequency starts at 950mhz.
If you are using diplexors, you know that one side is strictly for power pass
The key would be the amount of power that the reciever generates.
The legacy dishnetwork and Directv uses 13/18 vdc to power the Lnb
The DPPLUS uses 19/23 to power that beast of an Lnb
Cable co. do not use that kind of current to to send thier sig down the line, so if both cable and satellite use the same frequency 950mhz for example both will not interfere with each other because of the current they ride on even if you are thinking egress or ingress from the cable side, that has nothing to do with satellites even at the same frequency. an off air analog signal can interfere with a cable co. but not satellites even if the off air was at 950mhz. The LNB has something to do wth that Carrier to noise ratio. again which is powered by the reciever.
But like you said about keeping it simple and running seperate lines is good to do as well

 

[HCI]

Cable modem's _might_ work with diplexers on a sat line, the problem is the two bands are too close to each other, it may work fine for awhile, but it could interfere with each other at some point.

My guess is, each cable company's system is different. For example in my area where I am serviced by charter, they use 0-1000 MHz. This is what I was told by the Charter guy that installed my internet service. When I was working Comcast, the system ranged from 0-900 MHz, thus giving you a 50MHz seperation, depending on how strong the signal levels are, harmonics, localized RF emissions, etc, etc, it may work flawlessly for years, then again it maybe a problem.

Any Dish Network geek knows that Legacy equipment uses 950-1450 MHz, and Dish Pro/Dish Pro Plus uses 950-2150MHz. I have no idea what DirecTV uses frequency range wise, so I could not comment on that.

Sure you can combine signals at this point and share the same line, provided you have a channel that is not in use by the cable carrier.

As in my setup, I combined TV2 output on CH80 on my cable line to feed my 2nd television.

All in all, unless you know what frequency range is in use by your cable carrier, and there is enough spacing between on the sat line, depending on exactly how you want to configure it, DONT diplex sat lines and cable modem's on the same line.

Or if you really know what your doing, and you know the systems, you could probably get some traps from the cable co, place them strategicly based on the layout of the install and do some crazy things that'll make the next guy scratch his head on a service call.

Simply put, I'd probably just run new lines for Direct on the back half, and new lines for cable on the front half, keep it simple.

50MHz is way more enough gap than you need in any system.

The way a cable modem works is downloading data between the 6Mhz that are unused on a channel. This usually takes place in the 60Mhz to 850Mhz range while the uplink works below 60Mhz range usually in 5Mhz to 60Mhz with a 2Mhz separation.

Cable companies may very well transmit in and around 900Mhz but you would need a digital cable box to decode the signal which is unlikely if you have satellite, therefore the cable company would use a trap to block the high frequency's so they would never get to your house anyway. They use traps to block out any frequency that the sub is not going to subscribe to.

Again using a diplexer I will bet 999 times out of 1000 you will not have a problem at all.

 

[AntAltMike]

Only a few cable companies use frequencies above 860 Mhz, but as far as I know, no cable TV tuner box can decode digital programming above 860 Mhz, so any signals above 860 Mhz must be forward internet, but I have a spectrum analyzer and have not seen anything above 860Mhz in Comcast systems in Washington DC, Suburban Maryland or Northern Virginia, nor have I seen anything above 860 Mhz in any RCN systems I have serviced.

Cable TV off-air diplexers were originaly engineered to pass everything below 806 Mhz through one port and everything above 950 Mhz through the other. Such diplexers usually begin to measurably "roll off" at about 830 Mhz and attenuate cable channel 135 (860 Mhz) by typically five or six dB, which is generally not enough to cause any performance problems.

At the lower end of the TV side of a diplexer, they used to commonly say on their lables that they were engineered to guaranty the passing of frequencies as low as 54 Mhz (channel 2) or 48 Mhz (allowing one sub channel to go forward), and many said 40 to 806 Mhz, but cable boxes and internet modems use return frequencies as low as 10 Mhz, so the newest diplexers typically claim to pass signals down as low as 5 Mhz.

So basically, there are two diplexing problems involving DirecTV and cable: 1) DirecTV''s Ka dish used for HDTV block-shifts half of the Ka transponders down to 250 to 750 Mhz, therefore overlapping and conflicting with cable, and 2) if you are on a cable system that uses the frequencies above 860 Mhz for forward internet, they will get rolled off severely by the diplexer and be overlapped by the lowest Ku transponders.

DirecTV's new but as yet unavailable SWM technology allows up to eight selected transponders to be shifted to narrow bands above 950 Mhz that enable one DirecTV coax to support up to eight tuners and full service cable TV/internet with no conflict.

 

[HCI]

Only a few cable companies use frequencies above 860 Mhz, but as far as I know, no cable TV tuner box can decode digital programming above 860 Mhz, so any signals above 860 Mhz must be forward internet, but I have a spectrum analyzer and have not seen anything above 860Mhz in Comcast systems in Washington DC, Suburban Maryland or Northern Virginia, nor have I seen anything above 860 Mhz in any RCN systems I have serviced.

Cable modems use the unused frequency between channels. This normaly done below 850Mhz. Most of the time its on an unused channel to my understanding. I did some research on this and some of the numbers I quoted earlier was off by a couple of Mhz but check this out.http://chapters.scte.org/newengland/reference/Cable_Modems/PageOne.htm

Cable TV off-air diplexers were originaly engineered to pass everything below 806 Mhz through one port and everything above 950 Mhz through the other. Such diplexers usually begin to measurably "roll off" at about 830 Mhz and attenuate cable channel 135 (860 Mhz) by typically five or six dB, which is generally not enough to cause any performance problems.

At the lower end of the TV side of a diplexer, they used to commonly say on their lables that they were engineered to guaranty the passing of frequencies as low as 54 Mhz (channel 2) or 48 Mhz (allowing one sub channel to go forward), and many said 40 to 806 Mhz, but cable boxes and internet modems use return frequencies as low as 10 Mhz, so the newest diplexers typically claim to pass signals down as low as 5 Mhz.

So basically, there are two diplexing problems involving DirecTV and cable: 1) DirecTV''s Ka dish used for HDTV block-shifts half of the Ka transponders down to 250 to 750 Mhz, therefore overlapping and conflicting with cable, and 2) if you are on a cable system that uses the frequencies above 860 Mhz for forward internet, they will get rolled off severely by the diplexer and be overlapped by the lowest Ku transponders.

DirecTV's new but as yet unavailable SWM technology allows up to eight selected transponders to be shifted to narrow bands above 950 Mhz that enable one DirecTV coax to support up to eight tuners and full service cable TV/internet with no conflict.

You are right about the Ka Directv systems. This is one of the cases it would not work. Thanks for pointing that out.

 

[AntAltMike]

Cable modems use the unused frequency between channels. This normaly done below 850Mhz. Most of the time its on an unused channel to my understanding. I did some research on this and some of the numbers I quoted earlier was off by a couple of Mhz but check this out.http://chapters.scte.org/newengland/reference/Cable_Modems/PageOne.htm

I'm not sure what you mean by "the unused frequency between channels". There is no usable space between any adjacent channels except for the 4Mhz betwen channels 4 and 5. There is also 2 Mhz between channels 6 and 95, but I doubt that the cable company would use that out of concern that a strong ingress from a low frequency FM transmitter might screw it up.

The article you have linked to was written by someone from England, where band cutoff frequencies differ somewhat from ours. It may have been written before most cable systems were, "fully stuffed."

 

[HCI]

I'm not sure what you mean by "the unused frequency between channels". There is no usable space between any adjacent channels except for the 4Mhz betwen channels 4 and 5. There is also 2 Mhz between channels 6 and 95, but I doubt that the cable company would use that out of concern that a strong ingress from a low frequency FM transmitter might screw it up.

The article you have linked to was written by someone from England, where band cutoff frequencies differ somewhat from ours. It may have been written before most cable systems were, "fully stuffed."

There is alot of unused frequency between channels channels are given 6Mhz of space but don't use it all, but what I am talking about is the frequency on an unused channel. Anyone who has cable can flip through and see that there are some channels that have nothing on them. These are the channels or unused frequency that can be used.

http://computer.howstuffworks.com/cable-modem.htm/printable
http://en.wikipedia.org/wiki/Cable_modem

From above websites:

Extra Space
You might think that a television channel would take up quite a bit of electrical "space," or bandwidth, on a cable. In reality, each television signal is given a 6-megahertz (MHz, millions of cycles per second) channel on the cable. The coaxial cable used to carry cable television can carry hundreds of megahertz of signals -- all the channels you could want to watch and more. (For more information, see How Television Works.)

In a cable TV system, signals from the various channels are each given a 6-MHz slice of the cable's available bandwidth and then sent down the cable to your house. In some systems, coaxial cable is the only medium used for distributing signals. In other systems, fiber-optic cable goes from the cable company to different neighborhoods or areas. Then the fiber is terminated and the signals move onto coaxial cable for distribution to individual houses.

Streams
When a cable company offers Internet access over the cable, Internet information can use the same cables because the cable modem system puts downstream data -- data sent from the Internet to an individual computer -- into a 6-MHz channel. On the cable, the data looks just like a TV channel. So Internet downstream data takes up the same amount of cable space as any single channel of programming. Upstream data -- information sent from an individual back to the Internet -- requires even less of the cable's bandwidth, just 2 MHz, since the assumption is that most people download far more information than they upload.

Putting both upstream and downstream data on the cable television system requires two types of equipment: a cable modem on the customer end and a cable modem termination system (CMTS) at the cable provider's end. Between these two types of equipment, all the computer networking, security and management of Internet access over cable television is put into place.

In some cases, the tuner will contain a diplexer, which allows the tuner to make use of one set of frequencies (generally between 42 and 850 MHz) for downstream traffic, and another set of frequencies (between 5 and 42 MHz) for the upstream data.


................................................................

Maybe that cleared things up.
Any more questions.

 

[AntAltMike]

You are furnishing old, obsolete information. You can't "see", on an analog TV, that there is nothing on a channel that is already carrying digital data. I have a specrum analyzer and use it in the field. The dozens of cable systems I service are "fully stuffed". There are no vacant channels.

An NTSC analog channel needs the narrow guard space between the lower and upper adjacent channels. If you try to squeezer anything in that 1.5Mhz wide span, it will degrade the adjacent audio or video.

 

[HCI]

You are furnishing old, obsolete information. You can't "see", on an analog TV, that there is nothing on a channel that is already carrying digital data. I have a specrum analyzer and use it in the field. The dozens of cable systems I service are "fully stuffed". There are no vacant channels.

An NTSC analog channel needs the narrow guard space between the lower and upper adjacent channels. If you try to squeezer anything in that 1.5Mhz wide span, it will degrade the adjacent audio or video.

Obsolete huh. I know that DOCSIS is the standard used in todays cable modems. The following site will show you the frequency range used.
http://homepage.ntlworld.com/robin.d.h.walker/cmtips/signal.html

You are just trying to speculate that all my info is wrong when you can do a simple websearch and this info is on every website that comes up. You are telling me there is not an extra 6Mhz channel that is empty on any cable system. I don't buy it. Until you show me some type of proof I will take what research I have done to heart. If you show me something different I will gladly say I am an idiot.

By the way I found this on the FCC website. They would have updated if changes were made by now right.
http://www.fcc.gov/mb/engineering/cablemqa.html

How Does the Cable Modem Work?

This term "Cable Modem" refers to a network interface card that communicates with the cable network, sending and receiving data in two slightly different ways. In the downstream direction, the digital data is modulated and then placed on a typical 6 MHz television channel, somewhere between 50 MHz and 750MHz. Currently, 64 QAM (Quadrature Amplitude Modulation) is the preferred downstream modulation technique, offering up to 27 Mbps per 6 MHz channel. This signal can be placed in a 6 MHz channel adjacent to TV signals on either side without disturbing the cable television video signals.

In a two-way activated cable network, the upstream (also known as reverse path) is transmitted between 5 and 42 MHz. This tends to be a noisy environment with RF interface and impulse noise. Most cable companies use QPSK (Quadrature Phase Shift Keying) or a similar modulation scheme in the upstream direction, because QPSK is a more robust scheme than higher order modulation techniques in a noisy environment. The drawback is that QPSK is slower than QAM.

The transmitted signal from the cable modem, can be so strong that any TV sets connected on the same string might be disturbed. The isolation of the splitter may not be sufficient, so an extra high-pass filter can be needed in the string that goes to the TV-sets. The high-pass filter allows only the TV-channel frequencies to pass, and blocks the upstream frequency band. The other reason for the filter is to block ingress in the low upstream frequency range from the in-house wiring.

 

[stevo/65]

From what i remeber, is that each channel analog is 6 mhz " except between 4-5 " which is 10 mhz. In that 6 mhz you would have 3 different modulation process going on. You have phase modulation "what makes color in the video", amplitude modulation "which is the video" and frquency modulation "which is the audio part.
Now a 6 mhz bandwidth comes with upper and lower sidebands that is where the phase and frequency modulation kick in. I believe the video part actually takes up 4.5 mhz of the 6mhz "i may be off just a little" the phase and frequency modulation takes up the rest. You can still squeez info on those upper and lower sidebands.
From my understanding cable companies utililize the reverse stream as much as possible which is below the 55.250 mhz "channel 2" for phone and internet. I believe most systems reverse is 5- 32 or 42 "something like that" just as much as putting info on foward stream. Again it has been many years since i have messed with cable and alot has changed since i left the cable industry but i was there when digital compression was the sh*t.

 

[orbitallocation]

Hooking satellite with cable

If you want to be able to run a satellite system and cable at the same time; you have two options. The first way is if you have a seperate line for each service(one line for the cable service and the feed(s) for satellite), then you could plug the cable line into the back of the satellite receiver. You should see a port called antenae in. All you would have to do then is turn off your satellite receiver, then watch you cable that way. If you have a cable box, then you would run a line from the output on the cable box into the antenae input on the satellite box. Again all you would do is turn off your satellite receiver. Then use your remote for your cable box to change the channels.

The other way of running both services is when you have only one line going into the room where you want both cable and satellite. You would need two diplexers. On a diplexer you will see three ports, 1.in/out 2.sat 3.uhf. A diplexer resembles a splitter, but does not work like a splitter at all. The first diplexer will go behind your tv. 1. First you would hook the in/out to the wire that is going into the room. 2. The sat port will get hooked to the sat port on the satellite receiver. 3. And the uhf port will get hooked to the cable input on the cable box, or the antenae in on the satellite receiver. The second diplex will be put where are the wire meet up in the house, usually at the ground block and splitter(s). 1. The in/out port will be placed on the other end of the wire going into room. This wire can usually be found hooked to the output of a splitter in a cable system or on the ground block of a satellite system. 2 The sat port will be hooked to line coming from the dish or from the output of the switch. 3 The uhf port will get hooked from a output from the splitter from the cable system. And that is it. Some direct tv switches already have a antenae input built into them. Diplexers can also be used with off air antenaes and security systems.

 

[oljim]

Do it right the first time run cable to where you need it and the same with sat. do not mix the two and you will not have any problems.
As for hooking cable to a sat box, that is stupid. anyone feeding sat to TV with RF should be shot.
Use A/V or S cable

 

[Todd Humphrey]

CATV builds for the use of 5-1000 MHz. Just because they may not use up to 1000MHz yet does not mean they will not.
All satellite systems start at 950 MHz.

I do not think any satellite installer should be using diplexors to carry both satellite and CATV. In a pinch, and ONLY if the customer was told about the potential future conflict would I consider using diplexors to combine satellite and catv, but my general rule, is no, and when asked, I will say no.
The chance that CATV will move into the 900 MHz range is to great. As HDTV demand increases, you can bet CATV will seek to use all the bandwidth they can.

As far as CATV and satellite not interfering with each other because of the currant the signals travel on. HUH????
If you have RF energy in a coax at 950MHz from a satellite system, and RF energy at 950MHz from CATV, they will interfere. The DC voltage present on that line to power the LNB has nothing to do with the satellite signals propagation through the coax.