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Guest Message by DevFuse

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How a splitter works


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29 replies to this topic

#1 OFFLINE   veryoldschool

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Posted 18 November 2010 - 07:46 PM

Seems like this needs a bump from last year:

http://www.dbstalk.c...35&d=1261242163
http://www.dbstalk.c...36&d=1261242178


Now the green labeled have another part to them for DECA.
On the back side of the board is a filtered resistor circuit that bridges the DECA signal between the outputs
The loss is:
2-way = 8 dB
4-way = 11 dB
8-way = 14 dB

Without this added circuit the DECA loss would be the same as the isolation which is about 22 dB minimum.
A.K.A VOS

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#2 OFFLINE   Sim-X

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Posted 19 November 2010 - 07:56 AM

Thanks

#3 ONLINE   hdtvfan0001

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Posted 19 November 2010 - 07:59 AM

I vote Sticky.
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#4 OFFLINE   bobnielsen

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Posted 19 November 2010 - 08:42 AM

For those who want a bit more information: http://www.microwave...n_splitters.cfm

#5 OFFLINE   veryoldschool

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Posted 19 November 2010 - 09:10 AM

So to show what an 8-way looks like inside:

http://www.dbstalk.c...achmentid=23568

I've colored in one path that ends with two outputs and show the actual layout to the right. You'll see three more resistors have been added. These are to increase the bandwidth/frequency range.

Edited by veryoldschool, 07 August 2011 - 10:36 AM.

A.K.A VOS

#6 OFFLINE   veryoldschool

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Posted 19 November 2010 - 12:30 PM

Since these are all made up from the basic 2-way, there is very little difference between using a 2-way to feed two 4-ways, or a 4-way to feed four 2-way, or using one 8-way.

Why you might need to use a combination of these verses one, could be because there aren't enough coax to have home runs off the 8-way.

With the SWiM, you have about 25-30 dB of both splitter + coax loss before the signal drops too low at the receiver, which should be about what you have with an 8-way and 175' of coax.
Now if you have to use a 2-way at the receiver, and it's a long coax run, you could find you have problems using an 8-way to feed this.

One 2-way has about the same loss as 50' of coax.
One 4-way has about the same loss as a 2-way connected to another 2-way.
One 8-way has about the same loss as a 2-way connected to a 2-way, connected to another 2-way. This leaves about 150'-175' of coax loss between the SWiM and the receiver.
If you have to use more than 3 2-ways in line, then you need to have about 50' shorter coax for each added 2-way.

You can breakup "the pyramid" of the larger splitter, but should match all the legs equally between splitters and coax loss/lengths.

What you don't want to do is to feed a four way off another 4-way, because the last splitter output would equal a 16-way splitter and the coax length would need to be 50-100' total.
A.K.A VOS

#7 OFFLINE   veryoldschool

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Posted 24 November 2010 - 12:02 PM

http://www.dbstalk.c...=1&d=1290621499
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#8 OFFLINE   David MacLeod

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Posted 13 February 2011 - 11:05 AM

this was helpful to me the other day figuring out optimal "load" and balancing, thank you.
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#9 OFFLINE   PeteB

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Posted 13 February 2011 - 12:39 PM

This has been helpful to me, as well, but I have one question:

If you have two DVR's in the same cabinet and a 1x2 splitter, all else being equal, is it better to put the splitter right at the SWM, or with the DVR's?

Stated differently;), split upstream or downstream?

#10 OFFLINE   veryoldschool

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Posted 13 February 2011 - 12:43 PM

This has been helpful to me, as well, but I have one question:

If you have two DVR's in the same cabinet and a 1x2 splitter, all else being equal, is it better to put the splitter right at the SWM, or with the DVR's?

Stated differently;), split upstream or downstream?

It doesn't matter since the loss is a sum.
coax -> splitter = splitter -> coax.
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#11 OFFLINE   PeteB

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Posted 13 February 2011 - 12:59 PM

That was my guess; thanks!

#12 ONLINE   hdtvfan0001

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Posted 13 February 2011 - 01:07 PM

I just like all the pretty pictures VOS. :D

[Still say this should be a sticky :D]
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#13 OFFLINE   veryoldschool

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Posted 13 February 2011 - 01:13 PM

[Still say this should be a sticky :D]

what do you think it is?
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#14 ONLINE   hdtvfan0001

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Posted 13 February 2011 - 01:23 PM

what do you think it is?

:lol::lol::lol:
Meant to say "shoulda been" not "should be"... ;)

Plus..you got one more post out of it... :D
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#15 OFFLINE   David MacLeod

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Posted 13 February 2011 - 01:27 PM

That was my guess; thanks!

I think a lot (where to split) may also be personal preference. I tend to split close to IRDs to avoid long jumpers and if there is issue can fix (if needed) with short jumper.
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#16 OFFLINE   veryoldschool

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Posted 13 February 2011 - 01:46 PM

I think a lot (where to split) may also be personal preference. I tend to split close to IRDs to avoid long jumpers and if there is issue can fix (if needed) with short jumper.

I mount them where I use the least coax [being a cheap SOB]. :lol:
A.K.A VOS

#17 OFFLINE   David MacLeod

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Posted 13 February 2011 - 01:52 PM

:lol: me too, mines due to laziness though :)
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#18 OFFLINE   PeteB

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Posted 13 February 2011 - 01:59 PM

Well, I'll already have two home runs to behind said cabinet, which is why I said "all else equal", but I think I might split there so that I can use the other run for OTA if I end up needing it.

You can use an AM21 (or whatever the latest is now) with an HR24, right?

I'll be sure to keep the jumpers a little slacky so that my boxes aren't like shackled together... :)

#19 OFFLINE   veryoldschool

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Posted 13 February 2011 - 02:02 PM

You can use an AM21 (or whatever the latest is now) with an HR24, right?

yes, but this is a bit off topic
A.K.A VOS

#20 OFFLINE   liquidctv

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Posted 18 April 2011 - 03:54 PM

>What you don't want to do is to feed a four way off another 4-way, because the last splitter output would equal a 16-way splitter

Yep. 4x4 has never worked for me, despite many people yelling in my face that it should, and they have more experience than I do.




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