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A comment on Hunting for North Korean Fiber Optic Cables.

Re:Hunting for North Korean Fiber Optic Cables by mikkupikku on Monday December 08, 2025 @02:06PM (#46196286)
Do those small utility boxes alongside the tracks make sense for fiber optic? I expected things like that to be larger, if only because fiber has a minimum bend radius.

Edit: Good article though, I enjoyed it a lot.

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Re:Hunting for North Korean Fiber Optic Cables by adamcharnock on Monday December 08, 2025 @04:26PM (#46197862)
The min bend radius isn’t that large in my experience. On the order of 10cm IIRC, possibly even less.
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Re:Hunting for North Korean Fiber Optic Cables by Lukas_Skywalker on Monday December 08, 2025 @04:49PM (#46198131)
Even less is correct: outdoor fibers (G.652.D) have a minimum bend radius of about 30mm. The indoor counterpart (G.657.A1 and A2) have 10mm and 7.5mm.
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Re:Hunting for North Korean Fiber Optic Cables by lesuorac on Tuesday December 09, 2025 @12:45AM (#46201661)
Those are more of a technically no?

Like I have fiber to the house and you really need to pinch it and whatnot to cause an internet outage.

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Re:Hunting for North Korean Fiber Optic Cables by oarsinsync on Tuesday December 09, 2025 @08:58AM (#46204975)
A small bend radius means it can have a tight bend.

A large bend radius means it has to be a big bend.

A 7.5mm bend radius is really small. You can bend that stuff pretty tight before you create a problem.

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Re:Hunting for North Korean Fiber Optic Cables by eqvinox on Tuesday December 09, 2025 @07:15AM (#46204093)
The larger cables tend to have strength members with higher physical bend radius restrictions, i.e. you can't bend the steel or kevlar elements that tightly without breaking things.
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Re:Hunting for North Korean Fiber Optic Cables by st_goliath on Monday December 08, 2025 @04:32PM (#46197929)
Much smaller than that, some might even say a utility box is overkill: https://old.reddit.com/r/techsupportgore/comments/nvwcuh/the...
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Re:Hunting for North Korean Fiber Optic Cables by mikeyouse on Monday December 08, 2025 @04:34PM (#46197947)
Fiber’s perfectly happy being joined in 12” by 16” boxes for small runs. The terminal box in my garage has a few loops and is more like 6” x 8”.

https://www.seeclearfield.com/fiber-optic-wall-box/metal-wal...

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Re:Hunting for North Korean Fiber Optic Cables by whatsupdog on Tuesday December 09, 2025 @09:50AM (#46205494)
Railroad minimum bend radius is orders of magnitude bigger than fiber's.
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