baffled on how coaxial cable (cable tv) for old home

vote4Pedro

in the old house we have, we have 2 coaxial outlets for the tv (living room: CoA and office CoB). after getting comcast cable installed, CoB started working right away while the same tv (10incher CRT for testing) can't pick up anything for CoA.

after getting a tone cable tester i was able to deduct the that CoA and CoB must be on a splitter somewhere in the wall. they seem to go to the same connector basement (CoBasement).
the puzzling piece is that although both cables seems to be intact as basement connector can pick up the pulse from both CoA and CoB. CoA doesn't seems to be able to get a signal from comcast. Furthermore, connecting the tone tracer to the connector in the basement, both CoA and CoB can pick up the tone suggesting that it's indeed a splitter and the connection is good..


so lies the question.. why can't i pick up a tv single from CoA when CoB has no problems watching TV??? help before i start breaking the walls apart..

oberkc

Bad TV? Incompatible TV? Try swapping locations. See if problem follows the TV or stays with location.

vote4Pedro

i've actually tried 2 tvs.. one CRTand LED both led to the same result at CoA and CoB

Lockeset

Did you take off the wall plates and look for a splitter shoved behind the wall?

vote4Pedro

no, not yet anyhow.. the splitter is somewhere behind one of the walls.. (not ideal) but it seems to be working as i'm getting a tone pulse at both CoA and CoB with tone generator connected to the basement connector (CoBasement)

a7ecorsair

Is this tone generator designed to test coax in the frequency range that is used by TV signals?
Since the test TV works OK at one location but not the other, you have a problem with the cable system in your house.
Did the cables work before you signed up for comcast or didn't you use them?
How are you feeding your cables from the comcast connection, are you connecting at the correct point?
Since you say it is an older house, that would mean the cable was added so if there are two cable outlets, then there has to be a splitter somewhere.

joed

Most likely the splitter is at Cob. The cable runs from basement to Cob. There is a splitter behind B that then sends signal on to A. It's daisy chained. Not the best setup but the usually the cheapest.

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a7ecorsair

This makes the most sense. The splitter at Cob would be a two way with Cob on one "out" and a cable running from the other "out" to Coa

vote4Pedro

that is the most likely scenario.. however when connecting tone generator at CoA, nothing is detected at CoB while CoBasement is buzzing away.. is that normal behavior of a splitter? (i was under the impression they are all connected)

furthermore.. if it is the case of a splitter behind CoB that's not feeding properly.. how do i remedy that? new splitter?

edit: CoA and CoB are really just 20ft-30ft apart wire length wise.. i don't understand how there can be so much signal degradation this close.

a7ecorsair

You have to understand how a splitter works and is constructed. Feeding CoA will not produce a signal at CoB. Unless you really understand your tester, you will just be going in circles. Coax cabling is not rocket science. You need to use your eyes, a screwdriver, and a flashlight and start going through what you have.

McSteve

And it doesn't take much of a connection at all to pick up tone from a tone generator, whereas it takes a pretty good connection to be able to get a good TV signal.

You just gotta start pulling it apart, and checking stuff out. You've either got a bad splitter, a bad connection, or a bad cable.

Lockeset

I have a feeling one of the connectors worked it's way partially loose at the splitter location, or just a bad splitter altogether.

joed

Just remove the two connection cover and take a look. You could have done by now instead running around with the toner. It only takes 2 minutes to undo the two screws and look. There probably isn't even a box there. I have no idea what toner will do when trying to go through a splitter.

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vote4Pedro

the plates have been taken apart a while back. it's just a wall plate for coax with a coax cable sticking out.. not properly done at all. I'm afraid that the splitter is somewhere in the wall itself dangling between basement and 1st floor so it will be difficult to track down without doing some drywall damage,

Lockeset

That's odd to do. Usually it's buried in the wall where the plate is. Take a small mirror and flashlight and look into the stud cavity. If you can't find anything, look around the basement ceiling.