Subsea cable system costs are about 30k$ to 50k$ per kilometer. This is about the same cost as aerial construction, excluding the poles. You pay for the poles separately with yearly fees.
You also don't need roads to put up and service utility poles. It's just more convenient to put them by roads.
As an aside, you can and do have subsea cables with 216 or other high count strand numbers. The reason you use 12 strands or less in long haul systems is that it is cheaper to use fewer strands and higher bandwidth rates per strand than to build high count subsea cable systems.
You could build any terrestrial fiber system with just one strand, but it's cheaper and more convenient to use more strands since you are constantly bifurcating the network.
Source: I have built both subsea cables and terrestrial fiber networks.
> This is about the same cost as aerial construction,
Not even close. 12-count ADSS cable costs $3,000 per km, one tenth of your low-end. And for three times that price you can get 144-count which isn't even remotely an option for subsea cables.
I used to buy from FS.com, but they've stopped shipping large spools due to the COVID shipping disaster situation, and took the pricing down off their website. Here's another company (never dealt with them) charging $1,400 per km:
> Show me a 216-count subsea cable long enough to need repeaters/amplifiers.
I know reading is hard, but repeat after me: "The reason you use 12 strands or less in long haul systems is that it is cheaper to use fewer strands and higher bandwidth rates per strand than to build high count subsea cable systems."
If you want high count subsea cable segments with amps, but which does not use in-line amps, take a look at https://crosslakefibre.ca/
To spell it out for you, subsea cables which are only a few hundred kilometers long do not require in-line amps, only head end amps.
I don’t understand what your problem is? You can read, can’t you?
Google even pops up a box with the relevant information immediately. Here, let me help you if that’s too hard:
“The cost of completing the nascent fiber-optic network connecting the capital cities of Sub-Saharan Africa and the main submarine cables is modest at $316 million, based on a cost of around $27,000 per kilometer.”
And that’s just the top result. You can look up the per km cost of almost any cable system trivially.
Subsea cable system costs are about 30k$ to 50k$ per kilometer. This is about the same cost as aerial construction, excluding the poles. You pay for the poles separately with yearly fees.
You also don't need roads to put up and service utility poles. It's just more convenient to put them by roads.
As an aside, you can and do have subsea cables with 216 or other high count strand numbers. The reason you use 12 strands or less in long haul systems is that it is cheaper to use fewer strands and higher bandwidth rates per strand than to build high count subsea cable systems.
You could build any terrestrial fiber system with just one strand, but it's cheaper and more convenient to use more strands since you are constantly bifurcating the network.
Source: I have built both subsea cables and terrestrial fiber networks.