Rattler
join:2001-04-13
Havertown, PA
 ·Verizon Online DSL
 ·Verizon FIOS
| reply to Monjul
Re: Best splitter...does it really matter?
said by Monjul :
I would still look for the best splitter I could find. A standard splitter loses about 3db per tap so look for one that is only 2db down per tap which is what Verizon used in my setup.
Not sure where that idea might come from but even if the splitter were perfect, you'd lose 3 dB per each 2x split - it's just the way things work. In practicality, the loss is more like 3.5 dB for each split for a high quality, passive splitter.
Split 2x = 3.5 dB, each leg
Split 3x = 1x3.5 dB, 2x7 dB (usually)
Split 4x = 7-8 dB, each leg
Split 8x = 14-16 dB, each leg
There can be other splitter configurations that would yield slightly different numbers like 5-6 dB per leg on a 3-way or ~11-12 dB per leg on a 6-way.
The 6-way splitter they used on my install is marked 11.5 dB per leg.
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Never raise your hands to your kids. It leaves your groin unprotected. -- Red Buttons |
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KA3SGM
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Premium
join:2006-01-17
West Chester, PA
clubs:
·Verizon FIOS
| said by Rattler  :said by Monjul :
I would still look for the best splitter I could find. A standard splitter loses about 3db per tap so look for one that is only 2db down per tap which is what Verizon used in my setup.
Not sure where that idea might come from but even if the splitter were perfect, you'd lose 3 dB per each 2x split - it's just the way things work. In practicality, the loss is more like 3.5 dB for each split for a high quality, passive splitter. Split 2x = 3.5 dB, each leg Split 3x = 1x3.5 dB, 2x7 dB (usually) Split 4x = 7-8 dB, each leg Split 8x = 14-16 dB, each leg There can be other splitter configurations that would yield slightly different numbers like 5-6 dB per leg on a 3-way or ~11-12 dB per leg on a 6-way. The 6-way splitter they used on my install is marked 11.5 dB per leg. Rattler, put those numbers on a slope tuning loss, as the loss per port can vary 3-5db depending whether you are at 54MHz or 1000MHz.
Decent CATV splitters can be obtained by the names of PDI(Passive Devices Inc), Antronix, PCT, Toner,...
Monster is overpriced JUNK, and RatShack scares the heck out of me because you really don't know what you are buying.
Many splitters look better than others based on the frequency that the manufacturer is testing them at.
Then figure another (+/-1) DB for manufacturing inconsistencies.
They stamp out more than 5k splitters per hour in China, so you know nothing is precise, so to speak... 
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"Lithium is no longer available on credit" |
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Rattler
join:2001-04-13
Havertown, PA
·Verizon Online DSL
·Verizon FIOS
edit:
May 10th, @02:11PM
| @ KA3SGM:
I was just listing the approximate numbers that could possibly be expected for a decent unit - 2 dB loss per leg is just not possible on a passive splitter.
The 6-way splitter V* used on my install is a PDI and the insertion loss (11.5 dB) was marked on each output - I didn't see any test freq. listed.
I bought the R/S splitter (#15-2587) because I needed one ASAP and it was expensive for a 2-way (~$11). They had two types on the rack, one was rated at 5-100 MHz and this one was spec'd at 5 - 1100 MHz. Neither had any insertion loss numbers.
I used it to split the coax to my HD-DVR and the freebie DCT-700, at the wall plate. Both are working fine. The SNR on the HD-DVR @ 633 MHz is 36.5 dB/GOOD and no errors, with the splitter in the line. So with the 11.5 dB at the 6-way tap and maybe another 4-5 dB at the R/S 2-way, I still have a good signal at the HD-DVR.
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Never raise your hands to your kids. It leaves your groin unprotected. -- Red Buttons |
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KA3SGM
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Premium
join:2006-01-17
West Chester, PA
clubs:
·Verizon FIOS
| Rattler, whatever works.....
Do you have a Tellabs, or an Alcatel ONT??
I know the Tellabs ones run the Video pretty hot, between +18 db / +20 db, but not sure about the newer Alcatel ones.
I know I can run a single 16-Way splitter without problems off of a Tellabs 612, which is -16.5 db per port, but currently have the Router, ONT, 3 HD-DVR's and 2 SD boxes on a single 8-Way, with 1 port terminated and another jumping to a separate 6-way that feeds Analog(but not for long), QAM tuners, and 3 DCT700 Digital Adapters.
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"Lithium is no longer available on credit" |
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Rattler
join:2001-04-13
Havertown, PA
·Verizon Online DSL
·Verizon FIOS
| @ KA3SGM...
I have an Alcatel (my CO, Kirklyn, is GPON).
I don't know what the output level of the ONT is and have been kicking myself for not asking the install tech what it was... 
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Never raise your hands to your kids. It leaves your groin unprotected. -- Red Buttons |
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GeekGirl1
The Medium IS the Message
Premium
join:2007-01-28
Morrisville, PA | +18 dBmV |
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Rattler
join:2001-04-13
Havertown, PA | Merci, GG1 !!! |
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KA3SGM
- -... ...- -
Premium
join:2006-01-17
West Chester, PA
clubs:
·Verizon FIOS
| reply to GeekGirl1
said by GeekGirl1 :+18 dBmV GeekGirl1, Yes +18 dbmv is the Tellabs 612 Video Output Spec, but why am I afraid that you also tested it yourself to confirm that it was true?? 
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"Lithium is no longer available on credit" |
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lets456
join:2008-01-21
Hainesport, NJ
| Thanks for the replies. I had to have a tech come out to replace a panel on my ONT....the phone portion died. Anyway I asked him about the splitter and he said what most of you mentioned....about losing a certain amount of -Db every 25' or so then about how much you lose (-3Db) per split. However, he mentioned that when they install the bigger concern is having a signal that's too hot and need to attenuate down....so splitting many times is not a problem.
He said he did a house with 26 "splits" and was the only time he had to use and amplifier. |
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GeekGirl1
The Medium IS the Message
Premium
join:2007-01-28
Morrisville, PA
·Verizon FIOS
·Verizon Online DSL
edit:
May 17th, @11:10AM
| reply to KA3SGM
said by KA3SGM :GeekGirl1, Yes +18 dbmv is the Tellabs 612 Video Output Spec, but why am I afraid that you also tested it yourself to confirm that it was true??:p Have you ever known an engineer with equipment in-hand to not do otherwise? Of course I did (with the Verizon techs during the original install). Be very afraid. The saga continues: »10 way splitter |
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KA3SGM
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Premium
join:2006-01-17
West Chester, PA
clubs:
·Verizon FIOS
| said by GeekGirl1 :said by KA3SGM :GeekGirl1, Yes +18 dbmv is the Tellabs 612 Video Output Spec, but why am I afraid that you also tested it yourself to confirm that it was true??:p Have you ever known an engineer with equipment in-hand to not do otherwise? Of course I did (with the Verizon techs during the original install). Be very afraid. The saga continues: » 10 way splitter I have been meaning to pick up one of those cheap 'Sunrise 750' CATV Meter/Analyzers that pop up on ebay from time to time.
Only problem is that I know they have a 99% probability of being stolen property, so I tend to back away from what otherwise looks like a really good deal.
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"Lithium is no longer available on credit" |
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