Will switch work instead of 2nd line?

[Kenster]

My father-in-law has a recent Dish install with single receiver and a dual LNB dish with one line coming into the house. If we add another receiver, probably a 501, to the same TV, must we run another cable or can we handle this with a switch? The cable routing is a nightmare. The dish is mounted on a very tall, truss type tower next to a detached garage, about 50 feet from the house. The cable runs underground to the house, up under the vinyl siding then it had to fished between floors (there is absolutely no attic space) and down an interior wall to the TV. Surprisingly they did all this under basic installation with no extra charge. If we get him a 501, I don't know if they will do an install for him or not. I just thought a multi switch right behind the TV would allow the signal to be split between his basic receiver and the 501. The idea is for him to be able to watch one show and record another one at the same time.

[Neil Derryberry]

Unfortunately, you will need the second line from the dual lnb. What it sounds like you are describing is adding a splitter, which won't work here.

[Chris Blount]

Neil is right. In order to have another receiver, you must have a second line running from the LNB. A switch won't work because each receiver needs it's own switch to control.

The only work around is to hook up a switch behind the receivers with a DC blocker so one of the receivers cannot try to control the switch. The only problem is that the non-controlling receiver will only receive half the channels at any given time. It could work but is very cumbersome and not recommended.

[HTguy]

Originally posted by Kenster
My father-in-law has a recent Dish install with single receiver and a dual LNB dish with one line coming into the house.


I am wondering if you mean that he is just getting some special programming from one of the "wing" satellites or if he actually has a Dish500.

If he has a D500 he actually has either a TWIN or 2 dual LNBs (in which case they would be connected w/a SW21 switch.)

I would recommend a new "drop" for the 2nd rcvr in any case but if he has the D500 w/2 duals he will need another SW-21 to see both 119 & 110.

If it's just an 18" dish aimed at 61.5 or 148, or if he has a D500 TWIN the switch won't be needed.

[Kenster]

HTguy, I'm pretty sure it is a Twin dual LNB. I climbed the tower to have a look at it. I know there is only one cable from the dish. The dish says DISH 500 on it. Running anothera cable is going to be a real pain, as explained above. I guess I don't understand multi-switches. I know they are more than just splitters but, as in my case, if two lines from dish to switch can change to three receivers, why can't one line from dish to switch change to two receivers?

[Neil Derryberry]

It sounds like your dad has a twin lnb. The deal with the twin and its big brother the quad is that the multi-switch is integrated into the lnb, hence why there is only one cable coming out of the dish. At very least, if you can dismount the lnb, you will see the second coax connector for the second set. Save for installing another dish, it looks like you are going to have to run the second cable. Shame on the installer for not already doing this.

[scooper]

Kenster - he's got a Dish500 - 1 cable coming out. Now, is the LNB a single piece ? If it is (and I would bet on it), Your FIL has a TWIN LNB, not a Dual. The TWIN is the functional equivalent of 2 Dual LNB's and a SW42 switch (the SW42 has been discontinued).

Bad news - if you want to install a 2nd receiver, you're going to have to duplicate the cable routing, all the way from the TWIN LNB to the receiver. If it was me, instead of just 1 cable, I'd add 3 (leaving the extras disconnected, the house end there in the wall).

[Ryan]

Originally posted by Kenster
if two lines from dish to switch can change to three receivers, why can't one line from dish to switch change to two receivers?

Well, without going into depths about circular polarization and voltage switching, here's the low down.

A single-output LNB can really only see half the available channels at one time, but since you can only watch one channel on one receiver at one time, this is not an issue. The LNB can instantly switch from the first half of the channels to the second, upon a channel change, so it never really matters which half it 'sees.' It sees which ever half it needs.

This also holds true for each single output of a dual-output LNB. If each output is hooked up to a receiver, each side of the LNB might be looking at the same half, or they might be looking at the two different halves. But again it doesn't matter which, since the receiver only needs the half for the channel your watching.

But if you hooked up two receivers to a single output, you could never be sure which half you might need to see. Even if you used a DC block to make sure only one receiver controls which half (the half is chosen by sending either +13 or +18 volts up the line to tell the LNB at which half to look), the other receiver would experience periods when the half it needed to see would not be available.

Now the job of the multiswitch is to make one output of a dual-output LNB provide one half, and make the other output provide the second half. Then the switch provides which ever half a receiver requests. That's why you can feed a virtually unlimited number of receivers off one dish, as long as the switch has both halves from the dish.

Also, various channels may switch to which half they are assigned from time to time, so just because the two channels you want are in the same half today doesn't mean they will be tomorrow.

The reason for the two halves is more channels can be packed more closely together within a given frequency range. If you try to put both halves on one cable, they interfere with eachother.

Now that I've explained why you can't do it with one cable, let me explain how you might. I'm not sure if this works for Dishnet or not. It is a pricey option for DirecTV, but if you have no other option, it might be worth checking out and considering.

A device called a stacker will take the two halves and shift one half to a different frequency range, and in effect 'stack' it on top of the second half. At the other end a destacker allows you to pull the two separate halves out again, and feed them into two different receivers (or possibly a multiswitch).

Stacking equipment is expensive, but as the number of receivers served increases, the price drops because you only need one stacker at the begining and a separate destacker at each receiver.

I believe some DirecTV receivers actually have the built in ability to destack--I think it's some Sonys--and are used in apartment complexs and other large buildings where the landlord provides either satellite feeds or satellite subscriptions.

As for the viablity of stacking and dish network, I suggest you check the in the Dish forum for experienced users or installers.

[Kenster]

Ryan, thanks for the technical explanation.!

Scooper. The Dish500 in question has two separate
LNBs. I assumed they were both duals because I thought all new equipment was dual. Therefore, I thought this is called Twin Dual LNBs, but I could be wrong. Regardless, I think we will be stuck with running another cable. Maybe if he orders a 501 DISH will install the line for him.

[scooper]

So, if you have 2 Dual LNB's in your Dish500, when you go to the Multi Satellite point screen, then do a "Check Switch", you SHOULD find a note that found a SW21. Again, you would need to duplicate this setup from the Dish down to your 2nd receiver.

[HTguy]

The Dish500 in question has two separate dual LNBs....

Well, as soon as you told us it said "Dish500" we knew there were 2 duals...sort of.

Now, if they are physically seperated & each one has 2 ports you have a SW21 switch somewhere tying the 2 LNBs to the receiver and you will need another SW21 when you run the new drop to the 2nd rcvr.

If the LNBs are built into a single housing with 2 ports you have the TWIN. The TWIN has the switching built in so all you have to do is connect the new drop to the unused port.