"Fred Wilson" wrote in message
. ..
Hello all,

I have been having problems with my cable modem. I split the line where it
comes in the house. One leg to my modem, the other to the TV.

My internet kept dropping signal. I was sure to get a splitter that
provided a direct pass-thru to 7dB on both outputs.

There is a three way splitter on the line coming in from you pole. It has
output 7dB, 7dB, and 3.5dB.

Anyway, the cable guy came out and switched the hookup on the three-way
splitter. He took the line that goes to my cable modem and TV off of a 7dB
terminal and out it on the 3.5dB terminal. All is well now.

how is this possible?

The numbers on the splitter tell how much signal loss there is in the
splitter. To split a signal 2 ways requires atleast a 3 db loss. From that
you can split it more and each time you will get more loss. Internally your
splitter seems to split the signal to two parts and one goes to the 3db
port. The other goes to another internal splittter and that split gives you
the 7 db loss for each output. It is a log scale so that means a 3 db will
loose half the power, 6 db will loose 75% of the power, 7 db will loose
about 80 % of the power, 10 db will loose 90% . The db loss numbers add so
that 3 +3 = 6. There will usually be some fractions left over in the losses
so that is why you get 3.5 and 7 for the losses. Cable modems usually need
more signal to work than the tv sets. My cable comes to a 2 way splitter.
One goes directly to the cable modem and the other goes to another splitter
that goes to the other tv sets in the house. The modem works fine and the
TV sets (one with digital box, two with the basics) have good vidio on them.