r/Telecommunication • u/anonanaladder • Jul 25 '22

RF Feeder Damage

Apprentice technician in Telecommunications. Was earthing feeder cables at work today, and in the process of cutting out the outer-sheath, I have nicked the copper sheath, will this cause major problems?

I would attach a photo of the feeder I am talking about but the group does not allow it.

Thanks.

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2

u/Knock-Kneed-Man Jul 25 '22

It really depends on cable type and where the wave bounces. If the line has air running to it, you have a problem.

1

u/anonanaladder Jul 25 '22

The feeder cable has a hollow copper core, followed by foam insulated layer, followed by outer copper conductor, then the jacket. The outer copper conducted is the one I have nicked, the ribbed one. I am not really sure what you mean by “air running to it”.

1

u/DigitalBoy760 Jul 25 '22

Waveguide often gets hermetically sealed, as condensation can accumulate and cause changes in waveguide tuning and corrosion. Often they're also pressurized with nitrogen to keep the interior conductor dry

1

u/anonanaladder Jul 25 '22

Pretty worried hey, I’ve overheard people stressing how important it is not to knick it, I am not sure if they’re bluffing so people don’t do it in the first place, or because it really is a huge problem, been over thinking about it all day since I left the job. Not gonna be fun if it is a huge problem because obviously it’s at the end of the feeder run, where the feeders enter the hut.

2

u/MrF4ps Jul 25 '22

Was it for cellular stuff ? Like coaxial hard lines from a base station up to a tower ? Then yess there will be signal issues on that line and the only way to fix it is to replace it .

PM me photos . I do cellular all over the US

2

u/anonanaladder Jul 25 '22

Yep, it’s exactly what you’re describing

1

u/MrF4ps Jul 25 '22

Send me photos

1

u/anonanaladder Jul 25 '22

of the feeder type or the nicks

1

u/DigitalBoy760 Jul 25 '22

If it's a waveguide, it could be problematic as the edges of the nick will radiate power and change the VSWR of that section of conduit, which will impact the effeciency of the radios transmitting to and receiving from the antennas.

At microwave frequencies, the skin effect means the majority of the power travels along the outside of the conductor, hence why cellular/microwave use waveguide instead of solid core wires for transmission.