I need to split my cable feed into 4 to serve 4 rooms. I just realized I am
using a 1 to 6 splitter but only using 4 of the output and 2 were not hooked
I am wondering does this matter? Is one of those downstream cable getting
1/4 or 1/6 of the signal strength?
Should I get a better 1 to 4 splitter? I have a cheal AIM 11-4060 900MHz
As long as you have a strong incoming RF signal, unused outputs of
your splitter should not affect the signal quality.
However, a 4 output splitter divides the power of the incoming signal
more or less equally to 4 outputs. A 6 output splitter does the same
with 6 outputs. The sensitivity of modern electronics is such that
you can usually divide the power of the incoming signal several times
before it will affect signal quality.
Theroretically, an unterminated output functions the same as an
unterminated transmission line reflecting 100% of the power back in
the other direction. If this were a long line, it could cause ghosting
and other undesirable effects. In practice, the amount of reflected
power is usually so small that you do not see the effects or need to
worry about it. For critical applications however, they do sell 75
ohm terminating resistors with F connector threads.
Professional RF distribution systems also have taps available as an
alternative to splitters. A tap looks like a spliter accept it has
an RF in and RF out in additition to the RF tap outputs. The tap
outputs typically take a very, very small portion of the output power
from the main line. Taps are available in various power ratings. -20
dB, -14 dB, and -10 dB are typical. Taps might be used in
applications like a hospital, for example, where you might have 30 or
more receivers being fed off of a main line.
Optimum setup is a good 1 to 4 splitter but if you have good snow-free
picture in all rooms and a dependable internet connection, why worry. The
unused splitter terminals ideally should have 75 ohm terminators installed.
They should NOT have unterminated cables attached.
for basic cable from adelphia buffalo the answer would not matter much.
but for cablemodem service or digital hd tv quality and cableboxes you
want the cable company to do all that stuff for you.
if you do it and your digital box changes channels slowly or has
dropout, call them and they'll replace the bad wiring with no service
charge [buffalo ny]
with their technicians always busy changing out a cable end or splitter
or wire or box here every year and the electronic testers they bring,
it's a better job.
Cheap 900Mhz splitter...? Get yourself a decent quality 2.4Ghz splitter
(they are less than $5 in most electronic stores), it'll make a big
difference in signal quality.
My Father-in-law had a cheap splitter, and some old RG59 cabling, and was
splitting 4 or 5 ways also.. Had added a signal booster to try to get a
better signal, and it was acceptable to him, but pathetic in my opinion.
One day I bought a new 2.4Ghz splitter, instead of those cheapo ones you get
from the dollar stores, and replaced his wiring with decent quad -shield RG6
cable, removed the signal booster, and the picture quality went from
pathetic, to impressive for an analog cable signal. It was super clear, and
no boosters needed.
So don't underestimate the difference a decent quality splitter, and some
decent cables will make.
I got a 6 way splitter for him, and now using only 5 outputs, and didn't
terminate the open one, but doesn't seem to make a huge difference.
The output taps are getting 1/6 the signal at the input. Best practice
says you should terminate the unused taps with a 75 ohm resistor (they
sell special caps for this), but in reality it usually makes no
Tim Killian ( firstname.lastname@example.org) said...
For all practical purposes, leaving unused outputs on a splitter will not
cause any problems.
With transmission lines, they should be terminated with the proper
impedance in order to avoid reflections that can cancel or increase the
signal at various places along the line (like the interference pattern
generated when two stones are dropped into water).
At one extreme, if you shorted the line, the signal would reflect back
due to inductance properties of the line. If you leave the line open, you
get just as much reflection due to capacitive effects. When you terminate
it with the line's impedance (75 ohm for TV coax), no reflections occur.
With a splitter, the open end is so close to the signal source (in the
splitter) that there is negligible relection caused. If you took one of
those outlets and connected a cable to a wall plate in a room and didn't
hook up something to that outlet, then you should put a terminator on it.
"Never ascribe to malice what can equally be explained by incompetence."
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