What do these numbers on a cable splitter really mean?

Jul 09, 2006 27 Replies

replying to mm, im2late wrote: Actually that is incorrect. The ratings of -7dv, -7db and -3.5 db refer to the signal LOSS when the signal passes through those outputs. A two way splitter will lose 3.5 db on each output, but on some three way splitters, one output loses 3.5 and the other 3.5 loss is doubled on the 2nd and 3rd output (i.e.-7db signal loss per output.) I would suggest connecting your most "demanding" or important device to the -3.5 output on the splitter for less signal loss.

replying to Ralph Mowery, shawn wrote: hi so what is the differens from -17db to +15db? witch one is the bast? as i can understand-17db is be better than + 15db. thx

I don't fully understand what you are asking.

A splitter can not have a + db number. If there is an amplifier , then you can get + db.

Think of the signal starting out as 0 db. Any positive number will be gain, the larger the number,the more gain. Any negative number will be loss. The larger the number after the - sign will be greater loss. That is a -3 db would be less loss than -6 db.

Each 3 db is twice the signal or twice the loss. Every 10 db is 10 times. It is a log scale. Where 3 db is 2 times, 6 db is 4 time and 10 db is 10 times. 13 db would be 20 times the gain or loss.16 db would be

40 times the gain or loss.

Twice signal power is different from twice signal. You would need twice the voltage to double signal, or 4 times the power or 6dB. I like voltage.

Greg

replying to Ralph Mowery, Sean Peak wrote: I keep losing Internet service, I have 4 rooms for cable TV which is provided by my Internet service provider. Main line comes in to a 4 way splitter , main line to the Input, rest to tv''s and my Internet an I have good tv quality but costantly losing my Internet service. Why?

Hard to say. It may not even be your house. When I had problems with drop outs they found a connection problem two streets away. Could be your router, could be a connection. Have you called your provider? They have instruments to check signal.

It could be many things. At my house when I had cable TV and internet The man installed a 2 to 1 splitter where one side went to the cable modem. The other side went to another splitter that went to 3 TV sets.

At another house I lived in with no internet, but the same thing can apply. I lost or had very weak signals on several TV chanels, All other chanels were fine. Turned out to be a bad connector on the power pole where the cable came into the house. All the cable man did was cut off the connector and put another one on.

[snip]

I had such cable problems (frequent loss of internet connection, a lot of bup-bup-bup (erratic short audio/video dropouts) on TV, etc.). I had to have one of their (cable company's) technicians out. He was good and found a 30-foot section of cable causing an erratic 14dB loss. After replacing that, everything was OK.

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