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The official "ask veryoldschool" thread


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812 replies to this topic

#1 OFFLINE   Stuart Sweet

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Posted 08 January 2012 - 07:19 PM

Folks,

As many of you know we have a great asset in "veryoldschool", or VOS for short. He's forgotten more about RF and connectivity than many of us will ever learn.

I'd like to start by thanking him for his immense service to this forum, and I'd like to start an official thread for the many questions you all have for him about connected home, whole home viewing, or anything DIRECTV related.

Please keep to topic and if you have a question, please read on to see if it's been answered.

Thanks!
Opinions expressed by me are my own and do not necessarily reflect
those of DBSTalk.com, DIRECTV, DISH, The Signal Group, or any other company.

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#2 OFFLINE   veryoldschool

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Posted 08 January 2012 - 09:09 PM

Guess I should say hi to all and feel free to ask away. I've been answering [and will continue to] a lot of private messages. The idea here is to share the questions and answers as it may help others to have the same question, or something along the same lines.
DBSTalk has become a great place for information, and this is just another place to look for it. :)
A.K.A VOS

#3 OFFLINE   phoneman06

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Posted 09 January 2012 - 11:22 AM

Is there a minimum length of the coax between the PI29 and SWM16 when using a standalone connected to the power port of the SWM16? I thought I read somewhere about it needing to be at least 15 feet. My cable is only about 16 inches long and I was worried it might hurt something. Everything is working fine.

#4 OFFLINE   veryoldschool

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Posted 09 January 2012 - 11:28 AM

Is there a minimum length of the coax between the PI29 and SWM16 when using a standalone connected to the power port of the SWM16? I thought I read somewhere about it needing to be at least 15 feet. My cable is only about 16 inches long and I was worried it might hurt something. Everything is working fine.

Going into the power [only] port doesn't have a minimum distance.
The 15' comes from the SWM8, and when powered by the SWM output.
This can be "shortened", if you use a splitter between the PI and the SWM8, or if you power a SWM8 through the #3 legacy port.

"Generally" the DC block in the PIs can cause some problems with RF if there isn't enough coax between the two. The SWiM and the DECA in the receivers has shown to have problems if the PI is too close. Using longer coax lengths or having a splitter between the two, ends up with a better impedance match and solves this.
A.K.A VOS

#5 OFFLINE   phoneman06

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Posted 09 January 2012 - 11:31 AM

Thanks for the quick reply. I am using the DC/PWR port on the SWM16 so I should be good.

#6 OFFLINE   Drew2k

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Posted 09 January 2012 - 12:16 PM

Is there a minimum length of the coax between the PI29 and SWM16 when using a standalone connected to the power port of the SWM16? I thought I read somewhere about it needing to be at least 15 feet. My cable is only about 16 inches long and I was worried it might hurt something. Everything is working fine.


Going into the power [only] port doesn't have a minimum distance.
The 15' comes from the SWM8, and when powered by the SWM output.
This can be "shortened", if you use a splitter between the PI and the SWM8, or if you power a SWM8 through the #3 legacy port.

"Generally" the DC block in the PIs can cause some problems with RF if there isn't enough coax between the two. The SWiM and the DECA in the receivers has shown to have problems if the PI is too close. Using longer coax lengths or having a splitter between the two, ends up with a better impedance match and solves this.

I'm glad someone asked this - never thought to make a change when I moved from the SWM8 to the SWM16.

VOS, applying this to my configuration (below), you're saying that I am safe to remove the 15' loop between the SWM16 and the PI and replace it with a shorter cable length?

(Ethernet CAT5 not displayed below. Follow the link in my signature to view the full setup.)

http://www.dbstalk.c...=1&d=1326132942

Attached Thumbnails

  • AV System 20120110 (DIRECTV only).png


#7 OFFLINE   veryoldschool

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Posted 09 January 2012 - 12:20 PM

I'm glad someone asked this - never thought to make a change when I moved from the SWM8 to the SWM16.

VOS, applying this to my configuration (below), you're saying that I am safe to remove the 15' loop between the SWM16 and the PI and replace it with a shorter cable length?

(Ethernet CAT5 not displayed below.)

http://www.dbstalk.c...=1&d=1326132942

If your drawing is correct: you need to move the coax from the PI [going to the receivers] to where the PI now connects to the SWiM-16. Then connect the PI to the middle connector [not currently used] on the SWiM-16. This way you can then remove the 15' loop.

"This way":
http://www.dbstalk.c...01&d=1261069733

The other option is to move the PI to the output of the splitter, but it seems easier to simply use the PWR connector and never need "to think" about swapping coax and receivers around on the splitter.

Edited by veryoldschool, 09 January 2012 - 12:29 PM.

A.K.A VOS

#8 OFFLINE   Drew2k

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Posted 09 January 2012 - 12:31 PM

If your drawing is correct: you need to move the coax from the PI [going to the receivers] to where the PI now connects to the SWiM-16. Then connect the PI to the middle connector [not currently used] on the SWiM-16. This way you can then remove the 15' loop.

Thanks for the fast response, VOS!

I just double-checked my actual setup: in my diagram I incorrectly had the cables swapped at the PI, so this is how it is actually wired:

http://www.dbstalk.c...=1&d=1326133812

This is how the DIRECTV installer set it up when he put in the SWM16 and replaced my WB68 and SWM8 last year.

So ... hopefully that doesn't change your suggestion, as I still want to eliminate that 15' loop.

Attached Thumbnails

  • SWM and PI.JPG


#9 OFFLINE   Drew2k

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Posted 09 January 2012 - 12:33 PM

VOS - I see your edit with the diagram... I'm going to change it to the way you suggest.

My SWM16 and the splitters and the PI are behind the TV console, so eliminating the 15' coil will free up some space back there!

Thanks!

#10 OFFLINE   veryoldschool

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Posted 09 January 2012 - 12:34 PM

Thanks for the fast response, VOS!

I just double-checked my actual setup: in my diagram I incorrectly had the cables swapped at the PI, so this is how it is actually wired:

http://www.dbstalk.c...=1&d=1326133812

This is how the DIRECTV installer set it up when he put in the SWM16 and replaced my WB68 and SWM8 last year.

So ... hopefully that doesn't change your suggestion, as I still want to eliminate that 15' loop.

"Yeah" I blew right past the in & output, and no it doesn't change anything. Do check my addition at the bottom of my last reply.
A.K.A VOS

#11 OFFLINE   Drew2k

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Posted 09 January 2012 - 12:39 PM

"Yeah" I blew right past the in & output, and no it doesn't change anything. Do check my addition at the bottom of my last reply.

OK, got it. Cool!

This is the PI-28 model power supply, so it looks different from the Power Supply in your image, so when I swap cables per your suggestion, which port of the PI-28 do I connect to the center port on the SWM? Also, do I terminate the unused port on the PI-28?

#12 OFFLINE   veryoldschool

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Posted 09 January 2012 - 12:42 PM

OK, got it. Cool!

This is the PI-28 model power supply, so it looks different from the Power Supply in your image, so when I swap cables per your suggestion, which port of the PI-28 do I connect to the center port on the SWM? Also, do I terminate the unused port on the PI-28?

"The red one", and the output [to RID] only needs a dust cap [but any cap will do].
A.K.A VOS

#13 OFFLINE   NiTruS

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Posted 09 January 2012 - 12:49 PM

how much, if any, performance upgrade will I get with 2-4port splitters vs. 1-4port & 1-8port in a swm16 config? worth doing?

HR34 & BBDECA off 4-port
3X-HR2X off 8-way..

Edited by NiTruS, 09 January 2012 - 12:58 PM.


HR44-500 - 65" Panasonic Plasma VT50
HR24-500 - 50" Panasonic Plasma
HR22-100 - 32" Dynex LED
HR21-100 - 32" Samsung LCD

SWM16-BBDECA WHMRV

#14 OFFLINE   veryoldschool

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Posted 09 January 2012 - 01:17 PM

how much, if any, performance upgrade will I get with 2-4port splitters vs. 1-4port & 1-8port in a swm16 config? worth doing?

HR34 & BBDECA off 4-port
3X-HR2X off 8-way..

For each 2-way split is costs about the same 5 dB as 50' of coax [at the high frequency end].

Maybe a break down of splitters would help:

http://www.dbstalk.c...=1&d=1326136326

As you can see a 4-way output has gone through two 2-ways, and a 8-way has gone through three.
Each time you go through one, it has ~ 5 dB of loss.
SWiM to receiver can only have 30 dB of loss, so the less splitter loss, the longer coax you can have.

Attached Thumbnails

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Edited by veryoldschool, 21 March 2013 - 08:37 AM.

A.K.A VOS

#15 OFFLINE   Drew2k

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Posted 09 January 2012 - 01:45 PM

"The red one", and the output [to RID] only needs a dust cap [but any cap will do].


Thanks VOS!

#16 OFFLINE   NiTruS

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Posted 09 January 2012 - 02:32 PM

For each 2-way split is costs about the same 5 dB as 50' of coax [at the high frequency end].

Maybe a break down of splitters would help:

http://www.dbstalk.c...=1&d=1326136326

As you can see a 4-way output has gone through two 2-ways, and a 8-way has gone through three.
Each time you go through one, it has ~ 5 dB of loss.
SWiM to receiver can only have 30 dB of loss, so the less splitter loss, the longer coax you can have.
The less loss total, the less rainfade you will have, "but" the rain can get heavy enough to end up with no signal too.


so not worth swapping 8-port for a 4-port?
thx for your help!!

HR44-500 - 65" Panasonic Plasma VT50
HR24-500 - 50" Panasonic Plasma
HR22-100 - 32" Dynex LED
HR21-100 - 32" Samsung LCD

SWM16-BBDECA WHMRV

#17 OFFLINE   veryoldschool

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Posted 09 January 2012 - 04:18 PM

so not worth swapping 8-port for a 4-port?
thx for your help!!

Guess it may depend if the 5 dB is worth the cost of the splitter.
A.K.A VOS

#18 OFFLINE   Diana C

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Posted 10 January 2012 - 10:29 AM

so not worth swapping 8-port for a 4-port?
thx for your help!!


What I have learned from reading VOS's posts and his analysis of various issues is that the fewer times you split the signal the better. The loss across an 8 way is the same as about 150' of cable (3 2-way splits at 50' each), or 15db of loss, half of the total limit. Using a 4-way instead is like moving your receiver 50 feet closer to the SWM.

Personally, I'd only use an 8-way if it were unavoidable.

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#19 OFFLINE   veryoldschool

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Posted 10 January 2012 - 11:55 AM

As customers are moving to the HR34 and a SWiM-16, more attention needs to be paid to the type of splitters being used.

Each of the SWiM-16 outputs have the same range as the other SWiMs. If you keep within the 30 dB range, you won't have 771 errors.

I don't like using larger splitters than needed, since they are an inefficient way of doing things. Unused ports need terminations, which are just wasting signal into a resistor, that otherwise would go the the receiver(s), while at the same time adding more loss.

This looks like it's becoming more important with the DECA networking and the SWiM-16s.
The DECA crossover in the SWiM-16 has loss, and the DECA signals also have to pass through the splitters on both sides of the SWiM-16 outputs.

If there is too much loss "end to end" the receivers with internal DECA will report system error 47 or 48, as the network bandwidth is reduced.
A.K.A VOS

#20 OFFLINE   O2BRich

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Posted 11 January 2012 - 05:48 PM

Going into the power [only] port doesn't have a minimum distance.
The 15' comes from the SWM8, and when powered by the SWM output.
This can be "shortened", if you use a splitter between the PI and the SWM8, or if you power a SWM8 through the #3 legacy port.

"Generally" the DC block in the PIs can cause some problems with RF if there isn't enough coax between the two. The SWiM and the DECA in the receivers has shown to have problems if the PI is too close. Using longer coax lengths or having a splitter between the two, ends up with a better impedance match and solves this.


VOS

The cable between the PI29 R1 and SWM1\PWR port of the SWM8 is less the a foot. Another 1 foot cable from the PI29 runs to a 4 way splitter.
I am not experiencing any issues should I be concerned?
Bruce
Direc TV Customer since 11/98

HR21-100 via HDMI - 60" Sony Bravia 3
HR20-700 via HDMI - 55" Samsung
HR22-100 via HDMI - 37" Toshiba
HR22-100 via HDMI - 32" Sylvania
Slimline 5, SWiM 8, Whole Home over Ethernet.




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