Splitting feeds from the dish . . . why not?

[dguest]

I have a Dish 500 system (single dish) with two lbf's. Each lbf has two coax fittings. The two cables from each lbf go to a switch (two) to combine the single from each lbf into one feed. I have one cable feeding each of my two receivers. I'm guessing that this is a legacy twin lbf as it's now a few years old.

I now have a HD DVR 921 which I want to use to replace one of the other receivers. It needs two cables by itself. Can I split a cable from my second receiver to accomplish this? I've read that you can't split the feed from a satellite dish like you can with cable. Why not?

Thanks.

 

[SimpleSimon]

It's not a Legacy Twin. It's a pair of Legacy Duals with a pair of SW-21 switches.

A Legacy Twin provides precisely the same function in a single housing instead of the 2 housings, 2 boxes, and 4 jumper cables.

Correct - you can NOT split the cable.

Why? Because it carries different signals based upon commands from the receiver.

If you replace your existing setup with a DishProPlus Twin and a DPPlus Separator for the 921, you will have exactly what you need, along with an input for a third bird if needed - like for CBS-HD which is on 61.5 and 148 (choose one).

It is by far the easiest answer - the trick is getting one and paying for it.

You may or may not qualify for CBS-HD, but that's a different thread - of which there are aready quite a few.

 

[TNGTony]

As Simon stated, you can't just split the signal. The problem in understanding the issue starts with a statement you posted:
"two cables from each lbf go to a switch (two) to combine the single from each lbf into one feed"

The legacy switch does not combine the signal; it switches between the two lines. Your receiver sends commands to the switch to tell it which gateway to open.

The other thing is that the LNB itself has to switch from odd to even transponders (different polarization to avoid cross channel interferance). Again the receiver tells the LNB to receive either odd or even transponders.

So if you just split the signal to two receivers and the two receivers send conflicting commands, then the switch and LNB have no idea what to do.

A smaller issue is that the receivers communicate with the switches and LNBs with different voltage outputs. If you split the signal, that voltage can get transfered to the other receiver and if you are REALLY unlucky, damage it making it useless.

See ya
Tony

 

[dguest]

Thanks. I'm amazed that the manufacturer doesn't provide more detailed installation documentation. But you guys have filled in the blanks. The wiring diagrams make sense now.

Simon writes: "If you replace your existing setup with a DishProPlus Twin and a DPPlus Separator for the 921, you will have exactly what you need, along with an input for a third bird if needed - like for CBS-HD which is on 61.5 and 148 (choose one)"

What about the DishPro quad LBN? Wouldn't that give me the ability to hook up four receivers without the need for separators and switches? What I need is two satellite feeds to the 921 box and one feed to the second box for a total of three. Actually, I'd like to replace the second box with a 501 DVR.

So, what I'll have is this: A single dish (I don't need Dish 300, at least for now), feeding a DVR 921 (two inputs) and a DVR 501 (one input). Again, will the DishPro quad work for that setup? And why does one DVR need two feeds while the other one only needs one? I thought they'd both need two so the machine could record on one channel while you're watching another. But then, the 921 has picture in picture so maybe that's it.

Thanks again.

 

[DRGingras]

dguest, the 921 has 2 tuners - thus the need for 2 lines in from the LNB/switch. The 501, however, only has 1 tuner.

As for the DP quad, I'll let someone else answer that, since I don't have a 921. I am using a legacy quad to feed the 2-tuner 721, a 6000 and a 4900.

Hope that helps,

Dave

 

[goose61282]

A 5XX has only one tuner. You CAN'T watch one channel and record another. Only the 721, 522, and 921 do that.

Yes, the quad allows four feeds. The tough part is running all those cables. I'd prefer the DPP Twin as you can get four feeds with half the wire, and therefore half the trouble. Both solutions come out at about the same price. Plus rather than having to run all new cables, you just have to climb on the roof and replace the lnb and put a DPP splitter on the end of the cable.

 

[SimpleSimon]

The big reason I recommened the DPP Twin is the input for the third bird.

Secondary reason is being able to use a DPP Separator (a simple little box) to drive the 921, while still leaving a feed for the other box. Saves running the extra cable.

Downside is no extra feed for a third box.

So, which is more likely for you - third bird (eg. CBS-HD) or third box?

 

[BobaBird]

I'd prefer the DPP Twin as you can get four feeds with half the wire, and therefore half the trouble.

Just a bit of clarification here, 4 feeds does not equal 4 receivers. The DPP Twin will support only 2 receivers. If both receivers are dual tuner models you can use DP Separators (not splitters) to get the required 4 satellite inputs.