"SteveBell" wrote in
:


OK, you made me get my manual.

The signal loss due to 75-ohm cable length will be 1.5-
6.09 dB
(37%-75%) for every 100 feet of cable, depending on
channel
frequency. 4dB is a good rule of thumb. But in your case,
the
length will be the same, you're just putting a splitter in
the
middle.

The splitter is the killer. A two-way splitter has about a
4dB
loss on each output (61%). For simplicity, assume the
signal is
cut in half. A four-way splitter is electronically the
same as a
two-way with another two-way on each output, so you get
8dB loss
on each output, leaving you with only one-fourth the
signal that
went in.

You also had a splitter outside the house that (two
cables,
remember) that cut the signal in half. The signal that
reaches
your bedrooms will be only 12.5% of the original signal,
and
even less because of the line loss.

These signals are often too weak to work with digital
equipment.
I can tell you from experience that your cable modem needs
a
full-strength signal.

Get a high-quality signal amplifier and install it before
*any*
of the splitters. Keep your runs as short as possible.


In other words, if possible, lose the splitter outside the
house and have only one line to the attic. Put a GOOD amp in
the attic on the one remaining line. Then wire in a four-
way splitter right next to it. Look around and find the
best splitter you can. There is a big difference in
internal losses between the cheap ones and the top-of-the-
line. Forget Radion Shack - find a reputable cable/home
entertainment installer and buy from them. If you can't
find one, go to www.grainger.com and pick out the best
there. Now, to make up for the feed you lost, find the two
shortest runs of the five you want. Feed them from one of
the outputs of the four-way splitter. That way the three
longest runs, or the three drops that have phones/cable
modems/etc. will get the most signal.

Also, make sure you get the F-connectors that solder on.
Any of the connectors that screw/crimp on and use the center
conductor of the RG-6 cable as the center contact will have
more loss and a higher likeleyhood of failure. And make
sure you are using RG-6, not RG-59 or anything else. The
few extra dollars spent here will be more than worth it.

I know this is confusing if you haven't worked with it, but
here is a nice little tutorial that should answer most of
your questions. Ignore any of the parts about combiners and
modulators, since you are not doing any of that.

http://www.hometech.com/learn/video1.html

If you have any other questions feel free to drop me a line
directly.