Hidden coaxial cable in the wall is not working

[panpaper]

I've been looking for a coaxial outlet in my room to hook up my modem. I removed the cover on a TV and FM outlet and found a coaxial cable hidden inside, but it has been physically cut and has no connecting head.

After reading up on how to splice and crimp coaxial cables, and a trip to the hardware store, I got it all set up. These are the steps I followed: https://www.homedepot.com/c/how_to_crimp_a_connector_onto_a_cable_HT_PG_EL

I connected the newly-setup cable to an outlet cover plate, and then connected my modem to it. However, the modem keeps getting stuck at the US indicator (US indicator keeps flashing, all other indicators are off, except power). I read up a bit online and found that it has something to with an upstream connection. I assumed that I might have done a step wrongly, so I cut the head off and started over. The problem still persists.

The modem I have is a Technicolor TC4350, I'm on Teksavvy's 150 mbps plan. I have not connected any computers to the modem. I know the TV and FM outlet works because I have one just like it downstairs, except the cable inside was not cut and is attached to the cover plate. The modem works when I connect it to the one downstairs. (When I say downstairs I mean it's in the same house). Every room in the house has a working coaxial outlet except for mine, so I'm guessing it's hidden because it was never set up completely.

The coaxial cable I'm using has some prints on the outside, it says "SHAW CABLESYSTEMS E113333A CM OR CATV (UL)C(UL) CMG 18 AWG COMMSCOPE Brightwire".

On my first try, I suspected that I might have left too much copper wire portruding from the F connector head I installed. I referred to a working coaxial cable and cut the portruding copper wire, but it still does not work.

Does anyone have a clue about what I might have done wrong?

The following is a picture of the outlet cover I have in my room. Thank you so much in advance!

 

[R_1]

is the cable active? is it connected to the main cable line? have you followed or toned the end of the cable and verified it is active or connected.
if it is disconnected you need to find the common point where they all meet. the trunk box. it will have a splitter for each coax in each room, yours may need and end and securing to the splitter.

 

[panpaper]

is the cable active? is it connected to the main cable line? have you followed or toned the end of the cable and verified it is active or connected.

Sorry I've never done this before so I didn't know there were other ways to test it. The cable is built into the walls, only a small part can be accessed inside a small space in the wall. I'm unable to follow the cable to its end. My dad's office is next to my room, and the coaxial cable in there is working, so I assume mine should be active too?

 

[R_1]

is the cable active? is it connected to the main cable line? have you followed or toned the end of the cable and verified it is active or connected.

Sorry I've never done this before so I didn't know there were other ways to test it. The cable is built into the walls, only a small part can be accessed inside a small space in the wall. I'm unable to follow the cable to its end. My dad's office is next to my room, and the coaxial cable in there is working, so I assume mine should be active too?

I agree but what should be and what is are vastly different.
in (usually the master bedrooms closet or attached garage) a closet there will be a metal white painted plate (around 1 ft by 2 ft) with a screw in each corner. this will be where all the wires converge and is the main line service access. if you had a tone generator and a probe you could use that to follow to the end of the cable.

 

[BFG-9000]

Installers do not leave inactive coaxial cables live because each unused end should be terminated with a resistor to avoid reflections that degrade the signal in the entire system. Whoever cut that wire should have disconnected the other end too.

 

[panpaper]

is the cable active? is it connected to the main cable line? have you followed or toned the end of the cable and verified it is active or connected.

Sorry I've never done this before so I didn't know there were other ways to test it. The cable is built into the walls, only a small part can be accessed inside a small space in the wall. I'm unable to follow the cable to its end. My dad's office is next to my room, and the coaxial cable in there is working, so I assume mine should be active too?

I agree but what should be and what is are vastly different.
in (usually the master bedrooms closet or attached garage) a closet there will be a metal white painted plate (around 1 ft by 2 ft) with a screw in each corner. this will be where all the wires converge and is the main line service access. if you had a tone generator and a probe you could use that to follow to the end of the cable.

What's that box called? Is it where the circuit breakers are?

 

[panpaper]

Installers do not leave inactive coaxial cables live because each unused end should be terminated with a resistor to avoid reflections that degrade the signal in the entire system. Whoever cut that wire should have disconnected the other end too.

That makes a lot of sense. I tried looking for the box where all the wires converge but I couldn't find it.

 

[R_1]

it may be on the outside of the house near where the cable comes into the house. the houses I pre-wired had the junction box in the closet.

 

[jsmithepa]

Dude, you have to ask, is the OTHER END of that cable connected to anything? where is it? You must deal/know where both ends are, can't just take care of one end and you are done, no-no-no-no. Cannot make this assumption.

The other end, could had been also cut, find it. U can test by using your TV, and a few coax extension cords. BTW, the FM tells me this cable at some point was hooked up to an antenna.

 

[Corwin65]

That looks like an old Rooftop Antenna connection that would give you TV or FM. As old and yellowed as it looks it fits.

 

[panpaper]

While we're at it, is it illegal to crimp a cut coaxial cable? I read that splicing a cable is illegal?

 

[jsmithepa]

While we're at it, is it illegal to crimp a cut coaxial cable? I read that splicing a cable is illegal?

The coax what comes from the street, yah, because that belongs to the cable company... but this is outdated info, it doesn't do you any good to splice (steal the real term) a provider's coax these days because the signal is encrypted.