Need help - no signal from TV antenna in the attic

[Shawn Hirn]

Hi,
I just moved in to the new house. There is a 4-way coax splitter in
the attic, which has one input and four outputs (to different rooms).
I know that previous owners had a cable (from the cable company). It
looks like the cable was going into the same splitter in the attic,
and then routed to rooms downstairs.
I want to use the TV antenna in the attic.
I tried connecting the TV antenna to splitter's input ­ absolutely no
signal is getting to TVs downstairs. I also connected the antenna to
each of splitter¹s outputs (which go to TVs) ­ exactly the same
outcome - not even a change in a static when I plug in the antenna.
I bought a TV signal inline amplifier from RadioShack ­ absolutely no
difference.
However, if I drop a 100' coax cable directly from the antenna in the
attic to the TV downstairs (bypassing the splitter and all of the home
cable wiring), the picture is crisp and perfect.
Can I run some tests to ensure cable continuation (from the attic to
rooms downstairs).
Does anybody know how I can get the signal from the antenna in the
attic to TVs downstairs?
Thank you.

My guess is the splitter is defective. Splitters are very inexpensive,
so try replacing it.

 

[RickMerrill]

My guess is the splitter is defective. Splitters are very inexpensive,
so try replacing it.

And old splitters were low freq. Replacing is a good idea.

 

[Jeroni Paul]

Why is everyone guessing the same? The poster said:

also connected the antenna to
each of splitter’s outputs (which go to TVs) – exactly the same
outcome -

which discards the splitter as a possible culprit. It must be these
cables going downstairs.

 

[Kenneth J. Harris]

If you are sure that the original poster means that he disconnected one of
the cables that goes downstairs and connected it to the cable from the
antenna. What he said could also be interpreted to mean that he
disconnected a cable from one of the splitter outputs and connected the
cable from the antenna to this output (which of course would do nothing).
Nothing surprises me anymore. Anyhow, I guess if all else fails he can
connect a known good cable from the antenna to a new splitter(plus amplifier
if needed) and run four new cables from the splitter down to his 4 tv's.
Not a terribly difficult job if you've done this sort of thing before.

Why is everyone guessing the same? The poster said:

also connected the antenna to
each of splitter’s outputs (which go to TVs) – exactly the same
outcome -

which discards the splitter as a possible culprit. It must be these
cables going downstairs.

 

[Ron]

You can't run four tv's off of a non-amplified antenna.  I'm surprised
they could run 4 tv's off of cable without putting in an amplifier
somewhere.  I guess I'm wrong about that, but the cable signal is
stronger than a passive antenna signal.   Get a radio shack tv signal
amplifier with one input and four outputs.  You'll need to power it
with AC.

Reread the post, he has an amp. Now granted, it's not a splitter/amp,
and that might make a difference, but there are ONLY two
possibilities.

Either the cable from the ant to the amp to the splitter is bad, or
the splitter is bad.

 

[RickMerrill]

You're absolutely right but I wouldn't call that an admission. I'd
call it an answer to the OP's problem.

As another poster said first, a 4-way unamplified splitter just will not
work with antenna, althought it will work with cable. This leads to a
solution for the OP: get an amplified splitter OR connect just 1 tv,
which I think they did.

 

[Jeroni Paul]

As another poster said first, a 4-way unamplified splitter just will not
work with antenna, althought it will work with cable. This leads to a
solution for the OP: get an amplified splitter OR connect just 1 tv,
which I think they did.

Even though it drops the signal by some dBs it still can work if the
antenna signal is good. It does for me, no amplifier required. Most of
the channels here come from the same repeater and are well equalized,
they remain strong enough for a snow free tuning after one or two
unamplified splitters.

 

[RickMerrill]

A typical cable drop is + 10 dB at the tap where the home connectds to
the CATV system. A four way splitter adds a -7 dB loos, beinging the
signal to +3 dB, to cover the loss in the drop & distribution wiring.
If your OTA signals are +7 dB or higher, an unamplifed splitter works
just fine. If not, it can be anything from a little snow, to an
unuasble picture.

You're right, of course. I was in my country-mouse mode and not thinking
of the city-mouse who gets a much stronger signal!

 

[UCLAN]

You want to measure the resistance of the center conductor, right?

Easy to connect to the coax, but what do you want to connect to at the
other end? The rods that stick out of the antenna?

It's easy to test coaxial cable, no matter the length. Simply screw on a
75 ohm termination cap at one end, and measure from center conductor to the
ground shield at the other end. The ohmmeter will read 75 ohms plus whatever
the impedance of the cable is.

 

[Geoffrey S. Mendelson]

It's easy to test coaxial cable, no matter the length. Simply screw on a
75 ohm termination cap at one end, and measure from center conductor to the
ground shield at the other end. The ohmmeter will read 75 ohms plus whatever
the impedance of the cable is.

Actually it won't. The impedance is at RF frequencies, the resistance is
at DC. The DC resistance of coax is close to 0, being the sum of the DC
resistance of the center conductor and the shield.

Resistance meters measure using DC or relatively low frequency AC, it
will be very close to 0.

Geoff.

 

[Ron]

As another poster said first, a 4-way unamplified splitter just will not
work with antenna, althought it will work with cable. This leads to a
solution for the OP: get an amplified splitter OR connect just 1 tv,
which I think they did.

Not with MY cable. That POS is what was in my current home when I
bought it and it was like watching TV in a blizzard.

 

[UCLAN]

Actually it won't. The impedance is at RF frequencies, the resistance is
at DC. The DC resistance of coax is close to 0, being the sum of the DC
resistance of the center conductor and the shield.

The OP's report of NO signal present is more indicative of an open rather
than a high impedance at some RF frequency

Resistance meters measure using DC or relatively low frequency AC, it
will be very close to 0.

Not with the 75 ohm terminating cap. It will be at least 75 ohms unless
there is a short somewhere in parallel with the 75 ohms.