What good are all-port power-passing splitters?

[equant]

What good are all-port power-passing splitters? What are they used for?

I have a hughesnet dish with an original LNB pointed at a satellite for only one channel. I'd like to split the output to three different Diseqc switches. I'd like any of three rooms to be able to watch this channel, or anything on another dish. This would mean each receiver would need to provide power, since any single receiver might not be watching that channel.

Doesn't it seem like this is exactly what an all-port power-passing splitter is good for?

 

[Mr Tony]

They can be used a couple different setups

They can be used to split the signal of a bandstacked LNB to multiple receivers or used to split the signal from a single polarity setup to multiple receivers

Technically you could use it any way you want but some folks are worried that if you selects a H transponder frequency on one receiver and a V transponder on another receiver you could blow something. Havent run into that yet and I've had a splitter on a single output LNB

The bandstacked LNB"s have only one polarity so that is why they work. I have a 4 way on my C-Band bandstacked LNB. Also I've seen folks use them on the old Primestar separate H & V output LNB's

Sounds like youd be fine with what you want to do. Just split the signal from the Hughesnet dish and hook it up to the diseqcs


Highesnet LNB-----splitter output 1---------diseqc switch 1
------------------------splitter output 2---------diseqc 2

etc

 

[equant]

Thanks Ice.

Have you (or anyone else) ever noticed that Diseqc becomes unreliable when using all-port power-passing splitters? I was using one with a single output cband lnb and another on a single output ku lnb; each lnb going to two receivers, Diceqc stopped working reliably. When I took the second receiver off-line (unhooked coax from back of receiver), it worked (still using the same splitters, but only one receiver.

Like this...

Cband lnb ----> splitter -----> 4port Diceqc #1 -------> receiver #1
________________+--------> 4port Diceqc #2 -------> receiver #2

... did not work.

 

[Anole]

just say NO to splitters:

Still trying to use those splitters, eh?
Even knowing the model, it's hard to get info on exactly how it's built inside, and how it will work in any given application.

Then, there's the question of impedance matching the LNB output to one or several receiver inputs.
Some splitters do not do that (others may do it poorly), and as a result have maximum signal loss.

You might be able to use a powered 2x4 multiswitch as a 1-in, 4-out buffer amplifier and splitter.
Others may see some fault with the idea (just crossed my mind), but it's worth discussing.
The fact that the splitter costs $3 and the multiswitch $25 does not change the facts:
. . . splitters should only be used with your off-the-air TV antenna, and even then, sparingly! -

As for diseqc switches passing power, there are many designs on the market.
Some may pass enough to run a small motor.
Others will blow out with a big LNB hooked to it!
Predicting how any unknown brand will work when connected to a non-standard setup is impossible.
If you're lucky, you may burn out the diseqc, and protect your receivers .
In other words, it makes a nice fuse.

 

[pendragon]

I would generally agree that splitters and switching don't mix well, but since splitters are inexpensive, it's probably worth a few words.

The power passing splitters I've come across use diodes from the 'output' ports to the 'input' ports. Because diodes will only let current flow one direction, this means the LNB will get the highest DC voltage out of all of the receivers. The diodes prevent this voltage from feeding back into the other receivers, so you should be protected.

If you're going to use a splitter, bandstacking LNBs make the most sense, but otherwise it's probably better to let one receiver be the master for setting the LNB polarity. If you are worried the other receivers might override this, you could always install DC blockers on those. If only one receiver is on at a time, you should be fine.

DiSEqC through a splitter may or may not be a problem. Let's say you have two receivers , both supplying 18 V nominally. If one starts modulating DiSEqC signals, it may 'win' through its diode on the positive part of its 22 KHz cycle, but the other receiver may win on the negative. This could chop the signal on each cycle leading to unpredictable results. If only one receiver is supplying DC voltage, with the other having a DC blocker, DiSEqC should work fine.

It's all about who is outputting the highest voltage at any given time.

 

[equant]

If only one receiver is on at a time, you should be fine.

I think this is my problem. I will almost always have multiple receivers on different channels (different dishes). Thus having a "master" receiver will not work.

All of the FTA setups I've seen look great if you're a household with one person, or where everyone watches TV in the same room. I have a mother-in-law I'm trying to accomodate.

After looking at the cost of multiswitches, new LNBs, and everything required to share 4 dishes, I'm thinking I should just buy her a motorized setup and issolate her completely from the equation.

 

[Anole]

the sky is clearing:

I have a mother-in-law I'm trying to accomodate...
After looking at the cost of multiswitches, new LNBs, and everything required to share 4 dishes, I'm thinking I should just buy her a motorized setup and isolate her completely from the equation.

Well, now we have a goal. This is no longer a general discussion.
There are a number of users on the forum who've built up systems much like what you've described.
The instant switching and permanent alignment of fixed dishes has its appeal.
Four LNBs and two (to four) receivers is no big deal.

It's not the major expense you think, either.
Just had a brainstorming & on-line shopping session with one of the members.
Can't remember all the details, but it seems we found the 4x4 multiswitches for around $25.
You'd use two.
And I've seen dual-output LNBs in the under-$20 range.
Four for you.
To that, you'd need to add a pair of 4x1 diseqc switches, which go for free to $5.
For two receivers.

But with two more diseqc switches, this would expand to four total receivers.
With two more multiswitches and necessary LNBs, you could grow to eight LNBs.
Check out our FAQ on Switches for details.

AND, those were powered multiswitches (which I prefer).
And most of the equipment was from our sponsors.

 

[emuman100]

I went and purchased an active L-band splitter and power inserter. This only works with one polarity, and it'll power the LNB (18V of course), amplify the signal to be split across many outputs, and split the signal to as many as 12 more outputs depending on the model, all in one RU. These are designed for one polarity, cable headend type setups where you have L-band sources and a lot of receivers. Also, it will only supply 18V to LNBs, and is mainly for supplying commercial LNBs with power. This splitter I have works beautifully and I love it. very little signal loss and everything is neat and organised in my rack. They are made by Quintech Electronics. More info at L-band Splitters (Zero Loss) for Satellite by Quintech

 

[pendragon]

Substitute a bandstacking LNBF and all receivers will have access to both polarities. However not all receivers cope well with bandstackers.

 

[Tron]

I went and purchased an active L-band splitter and power inserter. This only works with one polarity, and it'll power the LNB (18V of course), amplify the signal to be split across many outputs, and split the signal to as many as 12 more outputs depending on the model, all in one RU. These are designed for one polarity, cable headend type setups where you have L-band sources and a lot of receivers. Also, it will only supply 18V to LNBs, and is mainly for supplying commercial LNBs with power. This splitter I have works beautifully and I love it. very little signal loss and everything is neat and organised in my rack. They are made by Quintech Electronics. More info at L-band Splitters (Zero Loss) for Satellite by Quintech

Nice solution, especially if you are going to use bandstacked LNBs as Pendragon suggested. Frequency range up to 2150 mhz suggests the device will handle the bandwidth.

 

[Mr Tony]

Substitute a bandstacking LNBF and all receivers will have access to both polarities. However not all receivers cope well with bandstackers.

if it doesnt you just have to do some math

KU take the H transponder frequency from 24600 and turn it Vertical
C-Band if you get the Eagle Aspen one just lower the frequency on H 600 mhz