View Full Version : Question about HDVR2/DSR7000

07-08-2003, 05:45 PM
This is about their dual tuner thing. If I just use a splitter (like what's on the 9thtee website) on the cable from the dish to my room, can I just hook up to both tuners that way?

Do I need to contact Directv at all?

I have the newest dish and RCA recievers.

07-09-2003, 08:38 AM
A splitter will not work. Each tuner needs direct access to each LNB mounted on the dish (it's most liklely a dual LNB, meaning there's two of them inside the LNB housing). The reason for this is that half the transponders on the satellites use right-hand circular polarity and the other half use left-hand circular polarity.

What you need is a multiswitch. A multiswitch contains splitters and A/B switches inside a single chassis that allows multiple receivers to access the required polarity signal independently of any other receiver. Each LNB output from the dish is connected to the multiswitch such that one LNB is dedicated to left-hand polarity transponders and the other LNB is dedicated to right-hand polarity.

The signal from each LNB is split to provide equal pairs of 4, 8 or 16 outputs. Each pair is then connected to an electronic A/B switch that is then connected to each individual receiver. When a receiver tunes to a channel, it sends a voltage of either 13 or 18 volts back up the coax line to indicate which polarity signal the transponder is using. This controls the A/B switch to select the correct LNB input that corresponds to the channel/polarity you wish to view without affecting any other receiver connected to the multiswitch.

If you have one of the newer oval dishes with two or three LNB mounts then you'd require a multiswitch with either 4 or 5 inputs. A single round dish gets it's signals exclusively from the 101-degree satellite. An oval dish with two LNBs gets signals from both the 101 and 119-degree sats. If you have a 3rd LNB in the middle it gets its signal from the 110-degree sat in addition to the other two.

The two-LNB dish has two dual LNBs so you need a multiswitch with four inputs to accommodate each one. The multiswitch used works the same as a two input switch but the additional two inputs use a 22kHz carrier frequency in addition to the 13 and 18-volt switching voltages. The three-LNB dish uses a 3rd single LNB with a total of five outputs. This 5th output is combined with the output of one of the other LNBs to reduce the signal lines back to four.

A multiswitch with either 3 or 5 inputs uses the additional input to combine the signal from an external VHF/UHF/FM antenna or cableTV line with the signal from the satellites. The two sets of signals are separated at the TV using a diplexer.

So you see, using splitter will not work if you have two receivers trying to tune to different polarity transponders simultaneously. The LNB can only tune to one or the other with a direct connection. You can buy a multiswitch anyplace that sells DirecTV receivers and install it yourself.