You can buy a spool of 100km of "OTDR launch fiber" which is quite compact as it's just raw fiber terminated by two connectors. 100km sells for only $1400: http

You can buy a spool of 100km of "OTDR launch fiber" which is quite compact as it's just raw fiber terminated by two connectors. 100km sells for only $1400: https://aliexpress.com/item/1005006978999338.html https://aliexpress.com/item/1005006978999338.html which is well within his budget as it seems he spent over $1000 on this hobby project. He could have bought two spools for 200km, laid that on his bench, and call it a day, instead of driving around data centers only to achieve 160km :-) But that's just the lazy side of me talking. Heck he could even return the spools for a refund when he's done :-)