# What is better: coaxial couplers or splitter?



## allenn (Nov 19, 2005)

Recently, I had a legacy MRV converted to a SWiM / DECA MRV with wireless CCK. The installer ran the four Slim5 coax cables to a D* SWM16. He ran one short coax from the SWM 1 port to a D* 8-way splitter (green label). I have two HR24s which are each connected to a port on the splitter. I would like to eliminate the splitter and connect each HR24 to one of the two SWM ports on the SWM16, but the two coax cables are too short to reach the SWM16 SWM ports. I know this was overkill, but it's D*'s buck not mine. 

Should I leave the setup as is, or use coaxial couplers to connect enough coax to reach the SWM16 SWM ports? Would this improve anything?

Side note: I am really liking the SWiM / DECA MRV and the wireless CCK. 

Thanks as always for the assist. Best wishes!


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## veryoldschool (Dec 10, 2006)

The 8-way splitter has a min of over 10 dB of loss, where a barrel would have less than 1 dB. This should suggest the barrel and a jumper would be better.


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## allenn (Nov 19, 2005)

veryoldschool said:


> The 8-way splitter has a min of over 10 dB of loss, where a barrel would have less than 1 dB. This should suggest the barrel and a jumper would be better.


Ok, I will remove the 8-way and couple the coax. Thanks for the information. Best wishes!

*Update 04/11/2012:* I removed the 8-way splitter, and I did not blow up anything. All is working as advertised, but I really cannot see a change in the sound or picture. Thanks!


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## litzdog911 (Jun 23, 2004)

allenn said:


> ....All is working as advertised, but I really cannot see a change in the sound or picture. Thanks!


Were you expecting to see a change in audio or video? Are you having issues there?


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## veryoldschool (Dec 10, 2006)

allenn said:


> *Update 04/11/2012:* I removed the 8-way splitter, and I did not blow up anything. All is working as advertised, but I really cannot see a change in the sound or picture. Thanks!


You won't see any change "until" the next heavy rainstorm comes through.
Without the splitter(s), you hold onto the signal longer than if you had them.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> The 8-way splitter has a min of over 10 dB of loss, where a barrel would have less than 1 dB. This should suggest the barrel and a jumper would be better.


Is that 1 db insertion loss typical for the 3 GHz rated barrels (usually with the blue insert) recommended for DBS service. Or the cheap 1 GHz CATV ones as well (usually with the clear plastic insert) found in stores virtually everywhere?

NOTE: And yes I'm aware DIRECTV does not recommend ever using those cheap CATV ones and of course would never use them on any coax run carrying the entire 250-2150 MHz Ka/Ku frequency stack. However I have been able to get away with using them on short to medium coax runs for distributing the SWiM and DECA signals.


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> Is that 1 db insertion loss typical for the 3 GHz rated barrels (usually with the blue insert) recommended for DBS service. Or the cheap 1 GHz CATV ones as well (usually with the clear plastic insert) found in stores virtually everywhere?
> 
> NOTE: And yes I'm aware DIRECTV does not recommend ever using those cheap CATV ones and of course would never use them on any coax run carrying the entire 250-2150 MHz Ka/Ku frequency stack. However I have been able to get away with using them on short to medium coax runs for distributing the SWiM and DECA signals.


I've only seen two different types of construction for barrels.

1) Those with a round female center pin, surrounded by dielectric. The loss of this type is so low that the mating of the coax may cause more [with a poorly made coax connector] loss than the barrel. It doesn't matter what color the dielectric is, since the dielectric constant will be the same.

2) Those that don't use a round female center pin, but instead have 2 fingers that grab the coax center conductor. This type isn't surrounded with a dielectric material, so has the dielectric constant of air [one], and only has a plastic cover.

Since these should have a poorer impedance match with coax, they should have more loss, "yet" this type of connector is used on the WB68, so it must not have significant loss either.

"The problem" with discussion of losses with barrels is it's theoretical, since actual measurements are extremely hard to make repetitively. The mating of the connector to the network analyzer [to make the measurement] will have as much or more to do with the results, than the barrel itself.

"In the real world":
1) a worn, dirty, or damaged barrel will cause more problems than the type of barrel it is.
2) I try to stay away from using more connectors, connections, barrels than I need, since each one is a point of failure, or discontinuity.
3) When I need a barrel, I'll pick a F-81 over the other type, but if I don't have one, then I'll use "a barrel" in good condition, to do the job.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> ... "In the real world":
> 1) a worn, dirty, or damaged barrel will cause more problems than the type of barrel it is.
> 2) I try to stay away from using more connectors, connections, barrels than I need, since each one is a point of failure, or discontinuity.
> 3) When I need a barrel, I'll pick a F-81 over the other type, but if I don't have one, then I'll use "a barrel" in good condition, to do the job.


So .... outside of these three considerations would you say not to really waste your money on the "DIRECTV approved" 3 GHz max. rated barrels. http://www.satpro.tv/barreladapterdoublefemalehighfreq3ghz100bag.aspx 

The ubiquitous cheap CATV 1 GHz rated ones will suffice even for cables carrying the Ka/Ku stack?


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> So .... outside of these three considerations would you say not to really waste your money on the "DIRECTV approved" 3 GHz max. rated barrels. http://www.satpro.tv/barreladapterdoublefemalehighfreq3ghz100bag.aspx
> 
> The ubiquitous cheap CATV 1 GHz rated ones will suffice even for cables carrying the Ka/Ku stack?



If my work was to be QA'd by DirecTV, then "approved" would be the choice.
If not, then http://www.summitsource.com/product_info.php?ref=1&products_id=7242 because they're cheap.
"In a pinch" I'd use your ubiquitous CATV.


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## allenn (Nov 19, 2005)

litzdog911 said:


> Were you expecting to see a change in audio or video? Are you having issues there?


Yes, I thought I would see a change in the video. No, I am not having any issues. But as VOS said:


veryoldschool said:


> You won't see any change "until" the next heavy rainstorm comes through.
> Without the splitter(s), you hold onto the signal longer than if you had them.


If it ever rains in the Atlanta area again, I will look for the improvement. Removing the splitter does clean up and streamline the SWiM cabling. I really like the SWiM / DECA MRV. Everything works better than with the previous legacy wireless ethernet MRV setup.



veryoldschool said:


> "In a pinch" I'd use your ubiquitous CATV..


I used two gold plated coaxial couplers: one to connect the coax for SWM1 port; and one to connect the coax for SWM2 port. I purchased them at Frys, and I do not know if they are good, bad, or indifferent. Hopefully, nothing blows up.

Best wishes!


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