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Q: Splitting Cable to Multiple TVs/Modem ( Answered 4 out of 5 stars,   1 Comment )
Subject: Splitting Cable to Multiple TVs/Modem
Category: Computers
Asked by: biosmith-ga
List Price: $10.00
Posted: 08 Aug 2005 06:31 PDT
Expires: 07 Sep 2005 06:31 PDT
Question ID: 553016
I just moved into an older home and had comcast cable installed on one
TV and cable internet installed on my PC.  I plan on wiring the rest
of the house TVs myself.  So in total I have the following to be
In basement- one digital cable TV and one cable modem
First Floor- one TV
Second Floor- three TVs
What is the best way for me to wire all these TVs and the modem,
without losing signal quality?  What combination of signal splitters
and signal boosters?
Subject: Re: Splitting Cable to Multiple TVs/Modem
Answered By: maniac-ga on 08 Aug 2005 09:34 PDT
Rated:4 out of 5 stars
Hello Biosmith,

I have basically the same set up (also using Comcast) and the
following explains how it is currently wired.

[1] I assume you have the main feed into the basement. [please make a
clarification request if this is incorrect] Suggest replacing your
current one input / two output splitter with a one input / four output
splitter. The four way split is just about the most I would do on your
cable feed. The four outputs go to the following places:
 - basement digital cable TV
 - basement cable modem
 - first floor TV (analog?)
 - second floor feed
It is pretty important that the cable modem gets a direct feed - see
for a brief description of cable amplifiers that work / do not work
with cable modems.

[2] On the line to the second floor, an amplifier may be necessary. In
one home I had, the amplifier was necessary, in another it was not.
YMMV. There are several good amplifiers available - a trip to the
local Radio Shack or electronics store should work. Alternatively on
line, you can search using "Froogle" at
for plenty of choices (note some are "bi-directional" and others are not).

Don't forget your amplifier needs power so it should be located near
an outlet. I happened to have an outlet near the attic light in one
house - that worked OK for me or it sounds like you have power near
the basement splitter, that should work as well.

[3] On the second floor, split the line using an one input / three
output splitter (or use a 1 to 4 & terminate the fourth output) and
send the three outputs to the rooms.

I would also terminate all unused connections (if any). That helps
improve signal quality and reduce possible interference from external
sources. I also invested in good cable connectors (gold) and the right
tools to make the connections - a little expensive at $100 or so, but
I found it was worth the money.

Good luck with your home wiring. Please make a clarification request
if you need some more sources of materials or if some part of the
answer is unclear.


Request for Answer Clarification by biosmith-ga on 08 Aug 2005 18:47 PDT
How powerful a booster for the second floor feed?  There are numerous
dB versions available.

Clarification of Answer by maniac-ga on 08 Aug 2005 20:13 PDT
Hello Biosmith,

The steps I would follow are something like this:
 - set up the basement and first floor connections, check everything works
 - run the second floor line and check quality on a single output
You may find at this point the combination of a long cable & the
fourth connection will require an amplifier.
 - add the rest of the second floor connections. Again, add (or
adjust) the amplifier if the picture quality is poor or you have
problems with the data communications.

In one home I had, the amplifier I used was picked up at Radio Shack,
something like:

This is a relatively modest amplifier (10 db) and has a  "two piece"
set up where you can separate the power from the amplifier - power is
sent across the cable & be sure to read the instructions carefully.
There are other amplifiers that are adjustable - for example:
has a small gain adjustment in the middle so you can adjust the boost
to prevent saturating the outputs. I suggest a gain adjustment if you
choose one of the more powerful units so you can still get the best


Request for Answer Clarification by biosmith-ga on 09 Aug 2005 06:40 PDT
One final clarification... in your answers you didn't mention surge
protecting the line.  Is it necessary, and a good idea, to surge
protect the main line in the basement in the case of lightening
strike?  What is the best way to surge protect?

Clarification of Answer by maniac-ga on 09 Aug 2005 13:45 PDT
Hello Biosmith,

About surge protection (or for that matter an Uninterruptable Power
Supply or UPS), it is most effective when EVERYTHING that is connected
together is protected. For what we have been talking about, that
 - power to the components (computers, TV's, signal amplifiers)
 - incoming signals (in this case - the cable TV, but a phone line
would also count if a modem was hooked up as well)
 - cables between devices are kept away from other cables (e.g., the
power lines) and if they cross, do so at 90 degree angles.
So if you do surge protection (or a UPS), make sure everything is covered.

There are certainly combination devices that provide surge protection
(or a UPS) for power, cable connections, and telephone lines. A quick
search on froogle for  "surge protection cable ups" brings up several
products (though note some don't protect cable TV) like
I use a UPS on my computer but do not have the surge protection on the
cable modem (I bought it when I used dial up) - something I will
probably go fix "real soon now".

Please note however, that there are limits to the protection of such
devices. I attended a computer conference session where they discussed
protection of high cost computer equipment [at a University located on
top of a hill...]. This campus got enough lightning strikes to damage
equipment about once a month and the fees for repairs were mounting.
They designed and deployed an effective surge protection system across
campus which worked until one of the buildings took a direct hit. Some
of the equipment within that building was fried but the rest of the
buildings and network was OK.

biosmith-ga rated this answer:4 out of 5 stars
Answer fit my needs with a few personal tweaks

Subject: Re: Splitting Cable to Multiple TVs/Modem
From: joelslc-ga on 29 Aug 2005 22:23 PDT
A good point to take into consideration when looking for a cable
amplifier ?booster? while using cable internet (or if you plan to use
digital cable TV) is that now radio shack (more recently known as "the
source") has bi-directional cable amplifiers, Allowing data transfer
to be amplified in both directions. I use a powered bi-directional 5
way splitter in my house, and it works beautifully.

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