# swm mrv green label splitters db loss



## swillotter (Nov 7, 2008)

could someont tell me the db loss for the 1x8, 1x4 and 1x2 green label splitters please...would it be better to run 1-1x8 and 1-1x2 or 1-1x4 and 2-1x2's for a 6 room setup with powered decca to internet? there are only 6 lines available and would be a brutal wall fish for a seperate internet line. thanks...the router is right next to a hr24. thanks


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## veryoldschool (Dec 10, 2006)

The green labeled have a mod circuit for MRV, which the others don't have.
The only splitters that publish specs are Skywalker:
2-way:

Insertion Loss (dBMax):
5-40MHz: 4.3
40-1000MHz: 4.4
1000-1750MHz: 4.8
1750-2050MHz: 6.2
2050-2300MHz: 7.3

Isolation (dB Min):
5-40MHz: 16
40-2300MHz: 22

4-way:

Insertion Loss (dBMax):
5-40MHz: 8.0
40-1000MHz: 8.3
1000-1750MHz: 9.5
1750-2050MHz: 10.8
2050-2300MHz: 12.6

Isolation (dB Min):
5-40MHz: 23
40-1000MHz: 25
1000-1750MHz: 23
1750-2050MHz: 24
2050-2300MHz: 22

8-way:

Insertion Loss (dBMax):
5-40MHz: 12.5
40-1000MHz: 12.5
1000-1750MHz: 14.0
1750-2050MHz: 15.5
2050-2300MHz: 18.0

Isolation (dB Min):
5-40MHz: 23
40-1000MHz: 23
1000-1750MHz: 24
1750-2050MHz: 23
2050-2300MHz: 22

Now the mod for MRV changes the isolation in the 475-625 MHz range to:
2-way = 8 dB
4-way = 11 dB
"I'd guess" the 8-way is 14 dB, but haven't measured one.

I would stay away from using other splitters with an 8-way, and instead use a 2-way with 4-ways off each output, or a 4-way with 2-ways off the outputs as needed.
Long cable runs would be best not to have additional splitters on them, so to keep the overall loss to a minimum.


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## pgiliber (Oct 17, 2009)

veryoldschool said:


> The green labeled have a mod circuit for MRV, which the others don't have.
> The only splitters that publish specs are Skywalker:
> 2-way:
> 
> ...


Are the splitter ports numbered so to speak? For example is the Red pass through port 1 and so on to port 8?

I ask because if you have a 1 x 8 but your only plugging in three receivers(2 dvrs and a non) does it matter which port you plug into on the splitter to keep the loss to a minimum....


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## veryoldschool (Dec 10, 2006)

pgiliber said:


> Are the splitter ports numbered so to speak? For example is the Red pass through port 1 and so on to port 8?
> 
> I ask because if you have a 1 x 8 but your only plugging in three receivers(2 dvrs and a non) does it matter which port you plug into on the splitter to keep the loss to a minimum....


The red port is marked because it's the only port that passes DC [power passing]. 
All 2, 4, & 8 way splitters are "balanced", so each port has the same loss.
This is kind of why you don't want to use a larger splitter than you need, because you'll suffer the higher loss and have to terminate the unused ports, which is sending the power into a resistor and "wasting it". It's better to use a smaller splitter, with less loss, and not waste any power into a resistor.


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## pgiliber (Oct 17, 2009)

veryoldschool said:


> The red port is marked because it's the only port that passes DC [power passing].
> All 2, 4, & 8 way splitters are "balanced", so each port has the same loss.
> This is kind of why you don't want to use a larger splitter than you need, because you'll suffer the higher loss and have to terminate the unused ports, which is sending the power into a resistor and "wasting it". It's better to use a smaller splitter, with less loss, and not waste any power into a resistor.


Sounds good thanks..I have one HR24 that keeps losing signal 771 but the other HR24 and H20 on that splitter are not. So I moved it to the Red Port and am watching to see if it happens again. If it does I am going to a 1 x 4.


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## DaaQ (Aug 21, 2008)

I cant look it up atm but what i think should be very closr to being right
I think its 2way= -4db. 4way= -6db and 8way= -12db or -14db. It is recommended to not use another splitter inline when using an 8way i do know that one 8way had more loss than 2 4ways.
Use the smallest splitter yoy can


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## veryoldschool (Dec 10, 2006)

DaaQ said:


> I cant look it up atm but what i think should be very closr to being right
> *I think its 2way= -4db. 4way= -6db and 8way= -12db or -14db.* It is recommended to not use another splitter inline when using an 8way i do know that one 8way had more loss than 2 4ways.
> Use the smallest splitter yoy can


"Think again". Just the power splitting with no insertion loss =
2-way 3 dB
4-way 6 dB
8-way 9 dB.
Now add in the insertion/matching losses for wideband splitters and you'll see what I posted earlier from Skywalker.

one 8-way as just slightly less than a 2-way + 4-way.


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## pgiliber (Oct 17, 2009)

veryoldschool said:


> "Think again". Just the power splitting with no insertion loss =
> 2-way 3 dB
> 4-way 6 dB
> 8-way 9 dB.
> ...


Well happened again last night, going to get a 1 x 4 and hopefully that is enough to stop the sat signal loss. Can I plug a receiver directly into one of the SWiM ports on the SWiM 16 and the rest on the splitter connected to SWM 2 port of the SWiM 16?
Just as a test until a 1 x 4 arrives.....


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## veryoldschool (Dec 10, 2006)

pgiliber said:


> Well happened again last night, going to get a 1 x 4 and hopefully that is enough to stop the sat signal loss. Can I plug a receiver directly into one of the SWiM ports on the SWiM 16 and the rest on the splitter connected to SWM 2 port of the SWiM 16?
> Just as a test until a 1 x 4 arrives.....


Sure.


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## DaaQ (Aug 21, 2008)

veryoldschool said:


> "Think again". Just the power splitting with no insertion loss =
> 2-way 3 dB
> 4-way 6 dB
> 8-way 9 dB.
> ...


So I did think about it again. Db loss on the green label splitters is
2 way is- 4db loss from port to port
4 way is- 9db loss from port to port
8 way is- 12db loss from port to port
this is from internal DTV documentation. At 2150mhz through 100 ft of RG-6 cable the loss is APPROXIMATELY -12dB. You GENERALLY lose- 30 to- 32 dN at the lnb.
The dBm RF power input should not be less than- 65dBm at any one tuners input or this.could.cause the MRV features to drop off.
It looks like you are referencing regular power pass splitters. 5-2300mhz splitters wont pass the 2.3mhz swm fsk frequency.


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## veryoldschool (Dec 10, 2006)

DaaQ said:


> So I did think about it again. Db loss on the green label splitters is
> 2 way is- 4db loss from port to port
> 4 way is- 9db loss from port to port
> 8 way is- 12db loss from port to port
> ...


"For the record" Skywalkers work fine for SWiM and pass 2.3 MHz quite well. They are only "rated" to 5 MHz, but the rolloff below is negligible. If these had the mods of the green splitters for DECA [which they don't] they would work fine for the connected home networking.

Sonora recommends -54 dBm @ the receiver for the SAT signal levels which will be the first to be affected by the splitter/cable losses, since the SWiM output is -30 dBm and this would only leave approximately 25 dB [to 35 using your minimum], where DECA levels are 20-30 dB higher and have 60 dB maximum from the internal tests and DirecTV engineering.

100' of "generic" RG6 @ 2 GHz = 9.34 dB, while RG59 is 11.7 dB.

Not sure what you mean by "You GENERALLY lose- 30 to- 32 dN at the lnb." A non SWiM LNB nominally outputs -15 dBm, and the SWiM is AGC'd @ -30 dBm.

If you've got documentation for the green labeled splitters, then I'll defer to this, since I haven't measured them, though the insertion loss doesn't seem to correlate between the 2, 4, & 8 ways, since these are all based on cascading 2-ways off each other.

Here's what the non green splitter looks like:








Which is very similar to the green labeled, but lacking the filtered resistive circuit connecting outputs for the DECA signal.
As you can see these are a Wilkinson divider.


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## pgiliber (Oct 17, 2009)

veryoldschool said:


> Sure.


Well plugged the problem child receiver directly into SWM port on the SWiM 16 switch and all worked fine last night, no signal 771 losses. Hoping that dropping to a 1 x 4 splitter will recover loss and it will work that way, although I could always leave it as is with 8 Tuners on a 1 x 8 and this problem one direct connect.


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## pgiliber (Oct 17, 2009)

Spoke too soon on everything working, one of my HR21's on the other 1 x 8 just experienced the searching for sat signal problem, this after i added three tuners to the splitter last night so I could directly plug in my problem receiver. This receiver was running perfectly for over a week before I added receivers to its splitter. 
So on the 1 x 8:
HR24
HR21
HR22
(2) H20's

This is ok on that splitter correct, 8 tuners.


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