atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Security, Alarms and Paging Siamese Coax cut, splice not working

Hi Y'all,

During a wire removal job I accidentally cut a siamese coax to a security camera. Both ends are terminated with BNC style connectors.

I did not have the right tools with me so bought a twist on female F type connector with a pass through and used wire nuts to splice the power cables (red and black). Camera does not work.

When I put my fluke intellitone 200 tone and probe on the coax i get tone at the other end from both sides of the cut when tested separately. When I put the alligator clips from my probe on the power cables from where it was cut on the side of the camera (so no power) the fluke changes tone whenever I barely move the wire as if it is shorted somewhere. I visually inspected the cable for about 15' in each direction from where I cut the wire and it looks fine.

Should the twist on F Type connectors work?

At this point I am contemplating pulling new wire but I do not have any experience with BNC connectors and assume they need thier own crimp tool (I have a crimp tool for F type). Can I buy twist on BNC's?

Thanks All!!

I have used f-connector to splice a run in the past with no problems. Did you use a splitter or a barrel connector? also did you confirm power with a DMM?

Yes you can buy twist on BNC's but I don't recommend them, nor the twist on F connectors. I use compression (snap n seal) fittings for everything: F, BNC, and RCA. These are what the cable companies are all using.

Maybe you shorted the power supply when you cut the wire ?

Test your power leads with an ohm meter make sure they are both good with no shorts.
Like Anthony said you can splice the cable with f connectors and double female. I use f connectors on the ends also and a f-bnc adapter much easier the messing with the bnc connector

Have you checked the fuse in the power supply box for the cameras?
When you cut the cable it should have blown the fuse.

Checked the fuses and all are good. Someone said that since the cable was originally terminated with BNC's that I need to splice with BNC's. Is that correct? I am going to go back out next week and splice with BNC's and hopefully that will do it..

Technically the F-Connector is not the "Best" connector for base-band video but if you are only talking terminating at the endpoints and maybe 1 splice in a shorter run then it's not that bad.

Like everyone else said, F-Connector should work, with worse case scenario having a little more signal loss (grainy/wavy picture).

Huh?

At worst case scenario a splice like this would have -1.5 db return loss. If your run cannot tolerated that amount of loss, run a new cable. I suspect you probably have a bad termination and did not properly manage the shield. I would stay away from the twist on and get set up with some compression F connectors.

i agree the compression connectors should fix problem, but i would test the power leads also.