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Discussion Starter · #1 ·

I have a previous question on here which in some what relates to this question.

 

Effectively I have four STBs plugged into 4 modulators with a coax cable coming out of each modulator. If i plug one of these cables into the TV it works as expected. If I use a combiner (I believe this is the correct name) 3x female and 1 Male. Then I can get all channels showing on the TV. The issue is that I am struggling to find a 4 port splitter.

 

I have managed to get another double adapter which when plugged into the 3 gives me 4 females and one male and the system does work, however, the quality is not great, a little bit snowy.

 

I was wondering if someone could possibly recommend me a four in (4 x female) and 1 out (1 x male) combiner so that all I send all the channels via this device. I would also like to try and amplify the signal to see if we can improve the quality. So any recommendations for a four in combiner to 1 out that amplifies the signal, I would be most grateful.

 

As a note, the modulators do have an aerial socket also, so I have tried daisy chaining the modulators, however, the quality is worse than when using the modified combiner.
 

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As long as the modulators are outputting different channels a 4-way splitter can be used as a combiner. To avoid interference you should set them to non-adjacent channels.
 
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Discussion Starter · #3 ·

Quote:
Originally Posted by olyteddy  /t/1523630/which-coax-splitter-to-buy-need-a-4-in-1-out-combiner-that-can-amplify#post_24512230


As long as the modulators are outputting different channels a 4-way splitter can be used as a combiner. To avoid interference you should set them to non-adjacent channels.

Many thanks for your reply olyteddy.

Just to clarify when you say non adjacent channels, the modulator I am using goes from 21-69. Currently I am using 21,31,41 and 51, presumably this is fine and you just mean not to use 21,22 etc.
 

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Quote:
Originally Posted by jonpaulapps  /t/1523630/which-coax-splitter-to-buy-need-a-4-in-1-out-combiner-that-can-amplify/0_40#post_24512526

Quote:
Originally Posted by olyteddy  /t/1523630/which-coax-splitter-to-buy-need-a-4-in-1-out-combiner-that-can-amplify#post_24512230


As long as the modulators are outputting different channels a 4-way splitter can be used as a combiner. To avoid interference you should set them to non-adjacent channels.

Many thanks for your reply olyteddy.

Just to clarify when you say non adjacent channels, the modulator I am using goes from 21-69. Currently I am using 21,31,41 and 51, presumably this is fine and you just mean not to use 21,22 etc.
correct.
 

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Residential modulators have an output of +25dBmV. Feeding it into a 4-way splitter/combiner loses 7dB, which gives you +18dBmV to feed into your distribution system. Enough to feed a dozen TV sets or more.
 

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Discussion Starter · #7 ·

Hi Egnlsn,

I didn't realise there was a restriction on the number of TV sets that could use this.

If you wanted to feed say 100 TV sets, how would you go about doing this with four separate inputs, ie four STBs that need to feed into one system and distributed to these 100 sets?
 

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Hi jonpaulapps,


It all depends on the number of splitters, what size splitters, the cable type, and the distance to the TV sets. After combining the modulators, you're starting off with 18dBmV. Then you just do the math. The FCC says no less than 0dBmV at the TV set [FCC Sec. 76.605 (a)(3)]. 18-X (for the splitter loss(es)) -Y (for the cable loss) = how much signal you have at any given location.


For large distribution systems, a distribution amplifier is used at the beginning of the system and throughout the system as needed. Taps are utilized in place of splitters to give a more uniform signal level at the outlets and minimize signal waste throughout the system.
 
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