Can I use DC-passed splitter to connect two receivers on one coax cable?

[hraner]

I'm using DISH network now and here is my config:

SuperDish 110W, 119W, 121W
DP34 switch(3 LNB input) with one coax cable out to my house
811 HiDef receiver

Right now I want to connect another receiver(bedroom) to the coax cable(together with 811 receiver), but at any time only one receiver will be used. Is it possible that I just use a Satellite Splitter(5-2150Mhz with both ports DC-pass) on the coax cable?

I know the better solution is to run another cable from the DP34 switch to the new receiver, but I can't climb over to the roof and do it

My worries:
1) DISH network is using DISHPro technology, the receiver needs to supply a 19V voltage on the coax cable, should I buy a one-port DC-pass splitter or two-port DC-pass one?
2) If both receivers are on, will they interfere with each other(19V voltage)?
3) I think the receivers need to send 22Khz DiSEqC signal to control the DP34 switch, will that satellite splitter pass this kind of signal?

Really appreciate your help, I'm a newbie on Satellite TV. Thanks!

[Mark Lamutt]

Welcome to DBSTalk! :hi:

The answer to your question is no. You have to run a second cable from the DP34 switch to your 2nd receiver location. There aren't any other options.

[hraner]

Thank you, but can you explain a little bit more on this? What's the problem? I saw that lots of places are selling this kind of satellite splitters, what is that for?

1) With DC pass, the switch/LNB will get 19V power from either receiver
2) With 950-2150Mhz splitter, two receivers will get satellite programming
3) Is that the DiSEqC/22Khz pass-through problem?

Thank you!

[Mark Lamutt]

Many more people qualified to answer this than me, but I'll give it a shot.

From the EKB:

Quick lesson: all DBS providers have up to 32 frequencies to use per orbital slot. The Frequencies are opposite polarities either even or odd. Legacy LNBFs and switches can only transmit one polarity at a time down the feed cable to your receiver. Legacy switches and LNBFs use a voltage signal from your receiver to change the polarity of the LNBF it is connected to, 13 volts is odd, 18 volts is even. Since voltage will drop as the length of the cable gets longer, at some point the attenuation of the cable will drop the voltage from the receiver below 18 volts so that the LNBF can't switch to the even polarity even though the signal from the receiver is 18 volts the LNBF is only able to use the 13 volt or odd polarity.

DishPro is different as it will stack or transmit both even and odd signals down the same wire, by shifting the frequencies up so both polarities can travel the same feed to the receiver or switch. Since this is the case the LNBF doesn't need the receiver voltage to switch back and forth. A switch is necessary to be able to connect one stacked 119° feed and one stacked 110° feed to each receiver. The only way a legacy receiver will work with this arrangement of LNBFs and Dish Pro switches is with a DishPro adapter that can down convert the stacked frequencies to the standard odd or even only frequencies. Each legacy receiver has to use this adapter which must be installed within 10 feet of the receiver.

So, each receiver stacks both frequencies on it's own coax line to the switch. The switch would have no way to determine how to control each receiver from a single line.

[SimpleSimon]

To expand on Mark's answer, ANY systems you've seen using a splitter are SINGLE satellite, DishPro feeds.

In other words, if your second receiver only needs to receive ONE of the three birds on your superdish, you can get a DishPro splitter and hook it between the LNB and the switch. Of course, that is NO help to you - if you can to the switch, you can run a second feed. ;)

[motorcycle_rider]

Simular topic. I am running a second line in the room where the tv is located at for my In-laws. I was wondering if I could use the splitter in this situation as there will only be one reciever hooked up. They want the option to be able to move the tv from one side to the other.

Thank You

[SimpleSimon]

You're much better off "switching" cables when the TV is moved (I assume it's ot going to be often).

What I mean is use a barrel connector, and hook up the needed cable when needed. ;)

[JohnH]

It is best NOT to use DC Power pass splitters unless the configuration specifically calls for it.

Since you say only one receiver will be used at a time, you should work on a configuration which only utilizes the 811. No second receiver fee involved. The standard 5-900 mhz or 1 GHz splitters are plenty good enough to split the RF signal out from the receiver, but one could consider the cable change configuration mentioned above or a reverse connected Hi-Isolation A/B swich. Either of these would yield more signal to the TV in use.

BTW: The most common use for the DC Power pass splitters is in C/Ku band systems to split the LNB signal to an analog receiver and a digital receiver. There are some Dual Tuner Receiver DISH Pro Plus configurations which may also use the Power Pass Splitters.

[hraner]

Thank you all for your reply, I did some technical analysis with a scope. btw: This is on a 3-LNBF SuperDish 121 setup, DishPro(950~2150Mhz for H/V transponders).

1) My 811 receiver is outputing ~20V all the time, even if it's OFF(but still plugged into AC). But some receivers are not outputing DC when it's OFF.

2) 811 receiver uses 22KHz DiSEqC signal to control DP34 switch, this is a +/- 0.6V DC signal which will be added onto the 20V DC. So with DC-pass splitter, 811 has no problem passing the 20V DC and DiSEqC commands onto DP34 switch. I verified this, I put a splitter between DP34 switch and 811 receiver(actually there are diplexers, but it's not relevant here), 811 works just fine.

3) DC-pass splitter has diode-protection, so DC can't go from input to output, only pass DC from output to input.

So here is the problem/solution:
1) Probably only one receiver behind satellite splitter can use DiSEqC to switch satellite. For example, 811 is outputing 20V, another receiver is outputing 18V, then only 811 can switch LNBF since the DC will be 20-0.6~20+0.6V. But the other receiver should still be able to get the signal (whatever LNBF 811 receiver choose), they can get different channels, but will be on the same satellite.

2) If 811 receiver's DC output is not always ON, such setup should be doable(both receivers only output DC when it's ON).

3) If it's a single satellite DISHPro configurion, then DC-pass splitter will work fine since all the signal will be availabile in 950~2150Mhz and we don't need to worry about LNBF switching, just make sure the splitter can pass DC.

The thing is in a prewired home, it's not so easy to run another cable from switch(at the roof) to one of the rooms, you don't want to cut the drywall, right? :)



It is best NOT to use DC Power pass splitters unless the configuration specifically calls for it.

Since you say only one receiver will be used at a time, you should work on a configuration which only utilizes the 811. No second receiver fee involved. The standard 5-900 mhz or 1 GHz splitters are plenty good enough to split the RF signal out from the receiver, but one could consider the cable change configuration mentioned above or a reverse connected Hi-Isolation A/B swich. Either of these would yield more signal to the TV in use.

BTW: The most common use for the DC Power pass splitters is in C/Ku band systems to split the LNB signal to an analog receiver and a digital receiver. There are some Dual Tuner Receiver DISH Pro Plus configurations which may also use the Power Pass Splitters.

[Jacob S]

Why not just run off of the cascade ports on the DP-34?

[CharlesA]

hraner:
You don't sound like a newbie.
The only thing you didn't know was the 811's output DC when turned off, which may not be common knowledge anyway.

My guess is you only have one cable entering the dwelling from the dp34 but does it connect to a junction area where all pre-wired coax terminate?

Guess you know you will either have to run another cable or wait for the 942 so you can backfeed output 2 to the rest of the dwelling.