I'd like to do a couple things at my house...
1) have at least one CATV "drop" in several locations - basement (for
the TV) 1st floor (for cable modem) and at least 2 bedrooms on 2nd floor.
2) possibly run CATV out to the garage (maybe 75' or so away) so I can
watch TV while working on car or hanging out upstairs.
I am ASSuming that I would want to add an amplified splitter at the
point where the cable enters my house, and then run individual runs of
coax to all the locations where I might want to hook up a TV or cable modem.
Problem is, I know nothing about this stuff. Can anyone recommend a
course of action?
replace "fly" with "com" to reply.
If you have a cable modem, the amplifier must be bi-directional. These
are expensive. There is a fair chance that an ordinary splitter will
suffice. Your cable company usually provides one as part of the
installation, and checks the signal levels.
Most cable signal is way stronger than it needs to be.
Most likely split signal will be just fine for you. If not
can install line amp excluding the one going to cable modem.
Quality coax, parts will give less signal loss/leak.
Could you explain the bi-directional amp comment?
I have a cable modem for Digital TV, Digital phone and Internet access.
When the cable company installed the modem they also installed what is
labeled as a "1-Way Tap". The main incoming cable is attached to the IN
port, the cable from the TAP port goes to the modem and the cable from
the OUT port goes to an pre-existing three way splitter. One of the
outputs from the 3-way goes to the digital cable box in the family
room, one goes directly to a TV and the other goes to the input of
another 3-way which has both TV's and more splitters attached to it.
The cable guy saw all the splitters and didn't seem to care. (It may be
that, in fact, he *didn't* care, if you know what I mean)
In all, I have 10 cable jacks in the house, 8 of which have devices
(cable boxes, TV's, VCR's or computers) attached to them at all times.
The 2 VCR's are always powered on (they are the tuners for 2 non-cable
ready TV's) as is the computer. It is not uncommon for as many as 5 (or
more) of the TV's to be on at the same time. I don't have any
amplifiers and I don't appear to experience any signal loss, although
some of the older TV's may be masking a poor quality signal by virtue
of their poor quality picture tubes. <g>
Anyway, I'm still interested in what you have to say about a
The amps aren't bi-directional really, it's just that they have a
passive return path so as to minimize their interference with the
upstream data transmission from the cable modem back to the head end.
THe cable modem has its own gain/amplifier for that path, and part of
it's "training up" in negotiation with the head end is setting that
gain. Without a passive return in an amp, the upstream channel is
pretty well doomed.
However, it is best to not have an amp in the cable modem's way at
all. The preferred method is to use a directional coupler (aka one
way tap) that has minimal insertion loss on the through leg, and 6dB
or so loss on the tap leg. The through leg goes to the cable modem
relatively unmolested, and the -6dB depleted tap leg gets run
that through an amplifier, to feed all bagillion outlets in the home
In one case I had in a house the cable modem was on the 2nd floor far
from place the cable came into the house. IN that case, they had to
use 2 directional couplers, and even go to the higher quality, more
directional couplers they refer to as DC9's to get low enough return
path loss to get a usable upstream path. And because there were tv's
on both floors of the home, 2 separate amplifiers were used, but none
was in the path to/from the cable modem.
The trouble with amplifiers, even passive return ones is that they add
noise, and all you need is one class about information theory to know
why noise is detrimental to data transmission.
Not all cable distribution amplifiers are passive; some are active and
have gain in the return path as well as the forward path. That can be
important when you have a number of long lossy drops but also need 2-way
communications (such as in VOD applications).
As Todd wrote in order to insure adequate signal while minimizing noise
levels you need to understand the distribution application thoroughly
before adding any kind of amplification. At a minimum you need to be
able to measure RF signal levels across the intended use spectrum.
Not always. I had a unidirectional Winegard in my cable circuit (Comcast)
for some years. Of course, the next time a cable tech showed up, he
encouraged me to get it out of the line (probably so they could once
again monitor my viewing habits), but I had no problems whatsoever with
cable operation for years with that setup.
Nazi: a person who is winning an argument with a liberal.
You probably don't need an amp, the incoming signal is likely strong
Home run all the RG6 cables from the drop locations back to a convenient
Get two splitters, a 2 way (3.5db loss per port) and a 4 way (7db loss
incoming cable feed to two way splitter IN. One output from this
splitter goes to the cable modem drop, the other to the four way
splitter IN. The four way splitters outputs go to your regular TV drops.
This minimizes losses on the cable modem feed. The ~11db loss on the
other drops will most likely be acceptable.
Put 75 ohm terminators on any drops not in use. Do not under any
circumstances use twist on connectors, use quality crimp or compression
types only. Make sure all connections are properly tightened. Don't use
more coax than you need on the runs but don't short them either, a few
feet of slack is ok, 50' is not.
Get your splitters from the cable company as they will be higher quality
that what you will find in most local stores. The cable company probably
won't charge anything for them. If it's a decent cable company they may
even provide the RG6 coax and connectors free or cheap to insure you use
the proper components since their FCC CLI performance is dependent on
The Cable you want to use is RG6/U Quad Shield. It should be labeled
as such directly on the cable (FYI it comes it white or black and is
carried by many electronic stores). Make sure it has the Quad Shield
on the label as otherwise it will be of inferior quality. There are
lots (and I mean lots) of bad substitutes, cheapie thin coax cables,
pre-made cables, etc. which you should do whatever you can to avoid
The problem with the cheap cables is twofold. They may have an
inferior shield that causes them to pick up terrestrial RF signals
(especially TV broadcast signals on the same frequency CH 2-13, which
are the same as the cable channels). This usually results in ghosts,
diagonal "banding" and a generally poor signal. These
poorly-shielded cables may also radiate the signal they carry.
Use professional connectors and the proper crimp tool for RG6/U. Make
sure the connectors are tight. All of them. They should be tight
enough that they are difficult to loosen by hand, but easily loosened
(or tightened) with long-nose pliers. Outdoor connectors should have
a waterproof cover of some sort.
Avoid using the amp unless you really need it and even then, split
before the amp's input for your cable modem. Amplifiers add noise to
the signal (especially hybrid analog/digital cable signals). Realize
that when you split the signal two ways, you are sending less than
half of the remaining signal to each TV. As said by another poster,
this is generally OK because the cable signals are usually strong to
begin with and the receivers are extra sensitive and usually have
automatic gain control circuits. If you split it 12 ways, you may be
approaching the limit to where an amp might do you some good.
Also, the load on the cable is the same whether the TV is on or off.
In other words, it doesn't matter how many TV's happen to be on at any
one time... The load is constant...and depends on how it is wired.
I have four RG-62, coax cables coming through a small hole on the
outside of my house, under the overhanging eves. All four cables are
terminated with a connector and marked with colored tape. The other end
of the cables go to various outlets inside the house. Inside the boxes
of each outlet, I have marked each cable with the same colored tape
code as on the end that's outside the house.
When the cable-company technician hooks on to the outside cables, I
explain the situation to him and allow him to take the responsibility
of making sure that the hookup works. A couple of years ago, however, I
had the cable company disconnected and I converted to satellite. That
conversion merely required connecting some short cables from the dish
to the outside cables with a coupler.
Cable techs are people too, and I've had enough experience with them to
say it's probably best to ignore anything they say.
I saw he was about to drill a hole in my brick wall from the outside
and stopped him.
He was trying to make a 200 foot run from one side of my house to the
other, the long way...because "it's not a good idea to use the crawl
space if you can avoid it" I didn't even ask why. I'm no engineer,
but I've seen many many houses with coax in the crawlspace. So I told
him "do not drill a new hole in my brick, if you can find one that's
already there, we can use that."
He looked around the foundation and said he'd take it in through the
crawlspace vent. I said "let's tap one bedrooms line, which is under
the house already, and run it to this other bedroom"
"I can't run it through the crawlspace..."
I took him in the house and told him where to put the receptacle, he
says "can't we just drill through the floor" Me, being a moron...said
"fine. I will put on some old clothes, then I will head down to the
crawl space, you feed me the wire and give me a tap and I'll make the
connection and attach it to your spade bit that you just ran through my
carpet and hardwood floor"
So, basically I paid the cable company $30 to send out a college kid on
a saturday to drill an unwanted hole in my floor (rather than putting
in a receptacle) and waste about 30 minutes of my morning because he
was afraid of the crawlspace or just didn't want to get down there.
He even gave me his flashlight and crimp tool before I went in.
Do it yourself, Quad shield is the best, rg6 is a little worse
shielding but is perfectly fine in my experience. Don't bother doing
it if you're gonna use that rg58 coax, it's cheap for a reason... not
nearly as good of shielding. And for pete's sake, never ever call the
cable company out and leave them unsupervised...I almost had a black
coax running all the way around my house about two feet up on beige
brick and a hole in my wall.
-> rant over.
I agree with all of your points. I always do all of my own inside cable
wiring by the way and I run the cables through the attic and then down
through the walls. I spent a couple of days, a year ago, running some
telephone line, coax and LAN wire from the attic all the way to the
basement. It was difficult to do because that particular wall happened
to have insulation in it. I tried fishing poles and everything else
before I finally figured out a way to do it. I actually wound up taking
some coiled up copper tubing that I had laying around and then uncoiled
it and shoved it down all the way from attic to the ceiling of the
basement. I took a hammer and a file and sharpened the end of the
tubing so that it would cut through the insulation.
I especially agree with personally supervising the technicians. I allow
them to make connections to the wires outside the house and I allow
them to install any required devices inside the house, but I specify
where those devices will be located.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.