Dual Coax

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laketime

laketime

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I was at a home today looking at another contractors work and saw that they used "dual coax" to every tv location. why would you need two coax's?
 
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laketime said:
I was at a home today looking at another contractors work and saw that they used "dual coax" to every tv location. why would you need two coax's?
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RH and LH channel RF spectrum require dual signal distribution having separate interface for channel range selection.
 
Or it is so some HDTV satellite systems can have two tuners active on a DVR. I am not a pro in this area, but I know DirectTV requires this on some of their systems.
 
Jacob S said:
Or it is so some HDTV satellite systems can have two tuners active on a DVR. I am not a pro in this area, but I know DirectTV requires this on some of their systems.
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I usually run (1) coax and (1) Cat5e to a main entry point.
 
gndrod said:
RH and LH channel RF spectrum require dual signal distribution having separate interface for channel range selection.
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Translation:

Satellite TV tuners, like DirecTV's for example, uses two lines to each tuner, which enables dual-tuner use. Some channels use right-hand circular polarization, and some use left-hand, which effectively allows two channels for each frequency.

Either of two DC voltages (12-13v or 17-18v) is superimposed on each line from each receiver to the multi-switch (or directly to the dish with only one dual-tuner) to determine which polarization your chosen channel's signal is coming from.
 
LarryFine said:
Translation:

Satellite TV tuners, like DirecTV's for example, uses two lines to each tuner, which enables dual-tuner use. Some channels use right-hand circular polarization, and some use left-hand, which effectively allows two channels for each frequency.

Either of two DC voltages (12-13v or 17-18v) is superimposed on each line from each receiver to the multi-switch (or directly to the dish with only one dual-tuner) to determine which polarization your chosen channel's signal is coming from.
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So then if new installations is it a good idea to run a dual coax and a cat5e homerun to each location?
 
I seem to recall, perhaps ten years back .... wasn't everyone excited about a 'new' cable then, for structured wiring systems, that supplied every plate with two coax and four Cat-5 cables?
 
dual satellite tuners. . .

but no longer necessary. echostar has been using a single cable for dual-tuners for quite some time, and directv went to the single-wire multiswitch a couple of years ago allowing dual tuners on a single connection.


but it could also be used for some type of in-house distribution
 
Brant is correct, When my sister originally had me wire her house for sat she had me run two to each location as per Direct TV for the older dual tuner DVR system, but a couple years ago when she upgraded to new quad tuner DVR receivers and I noticed they only had one cable hooked up so I asked her and she said it was no longer needed with the newer quad tuner receivers, 4 channels through one cable, why not all the channels are in the cable anyways, from what I understand the LMB's down link is brought to the multi-switch with the different polarization (vertical/Horizontal) combined at the switch and brought to the receiver on one cable now. cable has always done this at their main receiver station through multiplexers that would inject the different channels from the C-band satellite dishes into one cable modulated into the different channels we see each network on.

so I used the extra cable to bring her "over the air antenna" to each of here TV's which is up on a 120' tower as a back up on those days when her satalite goes out from bad storm clouds or heavy snow clouds which is rare for her with 106-110 DB signal level.
 
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laketime said:
So then if new installations is it a good idea to run a dual coax and a cat5e homerun to each location?
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Not after reading the other posts. :cool:

The only genuine future-proof installation is to run conduit to each location, or at least conduit stubs up to the attic and/or down to the crawl space.
 
For years some local cable companies around here required dual coax as the cable boxes had "A&B" inputs so they could provide more services.
 
iwire said:
For years some local cable companies around here required dual coax as the cable boxes had "A&B" inputs so they could provide more services.
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When I lived in Springfield, Va, (Fairfax Co., DC suburb), the cable company used two 60-channel cables, aka A & B, one of which also carried stereo music channels and Stereo FM simulcast of the movie channels, giving (analog) Dolby Surround with a surround decoder (which, of course, I had.)

I still have half a spool of their cable. It's beige-colored Siamesed twin dual-shielded RG-59 (not RG-6) with an identifying rib on one cable and, interestingly, I noticed that one cable's inner conductor has a thin clear-white insulation under the foam dielectric. Maybe a redundant cable identifier?
 
laketime said:
So then if new installations is it a good idea to run a dual coax and a cat5e homerun to each location?
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the day is coming where you'll only need an ethernet jack @ each TV location and one coax to the media server.

or you could use wireless, but i prefer wired.
 
I have run into many satellite dual tuners that require 2 input lines to the tuner and an additional line to be run out to a remote TV that is tuned by a RF remote control where the local tv is tuned by an IR remote control. Satellite company charges same monthly fee for a dual tuner as a single tuner so you have ability of 2 TV's with separate programming available at same price as you have for just a single TV setup, but the dual tuner location will need 3 cables run to it, or even a fourth if neither TV is in vicinity of the tuner.
 
kwired said:
I have run into many satellite dual tuners that require 2 input lines to the tuner and an additional line to be run out to a remote TV that is tuned by a RF remote control where the local tv is tuned by an IR remote control. . . . .
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good point; i didn't even think about that one.


but i have seen some of the newer receivers not require this for the TV2 output.

they now install a diplexer before the switch, and run the modulated output back to the diplexer. So basically they're running three separate lines @ the receiver back to one. They install a another diplexer/combiner where all the coax lines come out and use it to split off to another room.
 
brantmacga said:
good point; i didn't even think about that one.


but i have seen some of the newer receivers not require this for the TV2 output.

they now install a diplexer before the switch, and run the modulated output back to the diplexer. So basically they're running three separate lines @ the receiver back to one. They install a another diplexer/combiner where all the coax lines come out and use it to split off to another room.
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I see that too but they seem to want to avoid using diplexers if at all possible.
I hate satellite installers. Nothing like doing a nice neat installation on a $200-500K home then when you are there for some final items you see where the satellite guy thought you didn't run enough cables to some particular point and his install looks like hell. They don't seem to get the concept of concealing cables very well. Sometimes they are not easy to conceal but I have seen many that were run on surface that easily could be fished.
 
renosteinke said:
I seem to recall, perhaps ten years back .... wasn't everyone excited about a 'new' cable then, for structured wiring systems, that supplied every plate with two coax and four Cat-5 cables?
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Sounds like the CH structured wiring cable. I think they called it 'Siamese' cable. We did one house with it and it was a nightmare to run and terminate. It did what it was supposed to do, though, and it looked to be quality made. I don't see any on Eaton's site, but Smarthome has a type of it called combination cable.
 
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