Fiber Optic Cables

[Tyler]

Does anyone know if fiber optic cables put off EMI that will interfere with most detectors?

[phrunt]

No, fibre optic cables are just light.

 

[Knomad]

The cable itself does not put out any electromagnetic field that I know of, it is just carrying light, BUT there are transmitters generating those light pulses that can put out electromagnetic fields from the circuitry used to generate those pulses, and if not well shielded could put out what would be EMI.  It is most fortunate that the cables do not act like antennas, so presumably you would have to be very close to a transmitter or amplifier / repeater to pick that EMI up.

[phrunt]

I'm unsure how the US is set up for fibre, often countries that are not well into their fibre rollout will have fibre to an exchange then copper to the houses, that copper could emit EMI but I wouldn't think it would interfere with a detector much as they'll be either up on the power lines or buried well underground,   The fibre cables themselves will emit no Emi and can't get interference from EMI either.

We have fibre to our houses here, and fibre runs into our router which then we do our Cat6 and Wi-Fi connections.  We have the choice of 2000 Mbps, 4000 Mbps and 8000 Mbps, for my needs 2000 Mbps was more than I needed so I could go on a cheaper plan. 

These transmitters you speak of would be at the exchange building, and unlikely to be a problem unless you're detecting right there.  The cable itself running all around the neighbourhood will not be causing EMI issues.

Underground power is more likely the culprit for EMI coming from an underground cable.

[Tyler]

I’ve seen the cables that come to the houses here. It’s a small fiber with a small copper wire attached for locating when it needs to be marked. The main lines are in a 1 1/4 orange pipe right along the road ditches. They have recently come down into the rural area in my area along some of the roads where I hunt. I was hoping to not get any interference. Under ground Power lines, and phone lines are a pain. As well as electric fences. Believe it or not the fences are more of a pain than anything else. But all can vary day to day. 

[GB_Amateur]

8 hours ago, phrunt said:

I'm unsure how the US is set up for fibre, often countries that are not well into their fibre rollout will have fibre to an exchange then copper to the houses,

That's the old way and some areas probably still have that.  The new way is like yours -- optical fiber carries the signal all the way into the building (home, office, etc.).

The fiber cable between (neighborhood) junction box to private residence does have a fine wire, the purpose of which is to attach a transmitter so the fiber line can be traced by a detector.  But this is only activated for the purpose of utility line location determination -- e.g. when digging/excavation is going to occur and no one wants to cut the line.

In my yard, the fiber line is quite shallowly located -- less than about 6 inches (15 cm) deep!  I tried to pick up the line with a detector when it wasn't hooked to a transmitter and it did seem I could sense it, not by EMI but just from the presence of the fine wire.  Might have been fooling myself, though....