# 2 tuner PVR721/921 why 2 RG6 cables?



## scriabinop23 (Oct 8, 2002)

From what I understand a 2 tuner PVR requires two seperate cable inputs from the switch attached to the LNBs.

Why is this necessary when for example a 2 tuner PIP tv can simultaneously tune 2 seperate pictures from an ntsc cable or antenna signal via one input?

Why can't the PVR split the signal inside rather than make us buy a switch, make an extra cable run, etc. etc..

It just doesn't seem very sleek. Its the same signal coming in either way, so why can't the PVR just duplicate it inside?


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## Mike123abc (Jul 19, 2002)

It needs 2 cables because a cable can only carry one satellite's signal at a time (on non Pro line only half a satellite). If both channels you wanted to watch were on the same satellite it could just share a line. But, if you have a non DishPro you have from 4-6 different inputs to select from on the single line. A DishPro system would have 2-3 different inputs.

The reciever sends a signal up the line to switch across the different satellites as needed. With 2 lines it can watch 2 different satellites at the same time.


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## Karl Foster (Mar 23, 2002)

...because you can't run two separate signals down the same wire...

It is actually recording both data streams at the same time all the time when the machine is on. May not seem sleek, but it is a function over style issue, and it works great.


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## scriabinop23 (Oct 8, 2002)

> _Originally posted by Mike123abc _
> *It needs 2 cables because a cable can only carry one satellite's signal at a time (on non Pro line only half a satellite). If both channels you wanted to watch were on the same satellite it could just share a line. But, if you have a non DishPro you have from 4-6 different inputs to select from on the single line. A DishPro system would have 2-3 different inputs.
> 
> The reciever sends a signal up the line to switch across the different satellites as needed. With 2 lines it can watch 2 different satellites at the same time. *


now i see... 
finally i understand what 'switches' do (even though it sounds obvious'..

thanks for educating me!

so correct me if i'm wrong, the typical rg6 cable lacks the bandwidth for any more signal than that of one satellite? Thats something like a total of 4800mbps, right? wow.


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## Geronimo (Mar 23, 2002)

Please correct me if Ia m wrong but I also think the frequencies used at each slot are the same. So combining them might be tricky.


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## P Smith (Jul 25, 2002)

Selecting one channel suggest lock LNBF at one type of polarity and one frequency at receiver side - so for obtain second channel you should have at least second receiver and if the second channel required different polarity - second LNBF (or dual LNBF ).


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## Mike123abc (Jul 19, 2002)

Each satellite has 32 transponders with 24 MHZ spectrum each. So a satellite has 768MHZ bandwith. The old LNBs/switches would only send half at a time (even or odd). The new dishpro LNB/switches send both sides of the same sat at a time down one cable.

But there are 2 main satellites and 2 wing satellites (not to mention the funky Penn satellite). It is possible to select across 4 satellites at this time on Dish.

Each transponder is running about 30-33 Mbit/sec on it in 24MHZ spectrum. The enhanced HDTV ones are running about 40Mbit/sec over the 24MHZ spectrum.


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## P Smith (Jul 25, 2002)

With this DishPro LNBF's, switches and receivers ( I mean band-stacking feature) you need to use many receivers or that internal tracts (as 721 have 2 of them ), as many channels you want to watching and/or recording same time.


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