(GPS sync is a question of nanoseconds.)

You're citing things without understanding them.

First, you've mangled that summarisation, knowing an upper bound on delay is not the same as knowing delay.

Second, that's true for using TESLA for data streams. Not for when the timing of the stream itself is the information content. That bound on delay translates into a spatial zone of spoofability. The RFC refers to the content being timely (not stale) and authenticated, but timely is not the same as using the timing itself as data.

The difference with a quartz watch is that it's factory calibrated with the load capacitance on the crystal, and that it's a 32768Hz tuning fork. For a variety of reasons, generating higher frequency clocks off 32768Hz is... "annoying" (huge PLL ratio, very slow feedback loop step), and typical crystals in the 10-100MHz range are just less precise and thermally stable. (Not sure why, I'm not an oscillator manufacturer...)

(NB: you can of course correct for initial deviation in software. The actual problem is stability over temperature.)

Ed.: https://www.digikey.com/en/products/filter/crystals/171 (or, in the hopes the filter on the link works, https://www.digikey.com/en/products/filter/crystals/171?s=N4... ) - look at the options and prevalence for frequency stability & tolerance.

Ed.2: a wristwatch also benefits from being kept at constant-ish body temperature.

There's a reason GPS satellites are used as reference clock for PPS, PTP and NTP. A naval vessel you could carry a Rubidium clock on, I guess. But on ground vehicles or mobile receivers... nope.

[ed.: OCXOs aren't that large, 1cm^3 box ballpark, too large* for a smartphone or laptop but not a problem on larger quadcopters, cars or military radio equipment. And 1ppm is long term drift, you can try compensating a bit beyond that, so - I guess it's a question of spending the money and energy** on OCXOs.

* thick specifically, can't easily be made thin AFAIK

** the first O there is Oven - roughly 0.5W continuous draw.]

39C3: "Who cares about the Baltic Jammer?" / "Terrestrial Navigation in the Baltic Sea Region"

First few minutes give a summary, remainder is about DLR's attempt to fix it.

Also, https://gpsjam.org/ (ADS-B data from planes, hence limited coverage area.)

I don't think I've ever seen a place fully compliant with all regulations down to the last letter. Somebody inevitably takes a shortcut somewhere. All you can do is push those shortcuts into places they don't matter.

Certainly not the times and culture we live in, but the "test" they tried running at Chornobyl violated their own regulations too…

  create file
  chmod 0600 file

  umask 077
  create file

The sibling posts have already pointed out the pricing has mostly equalized at this point too, especially if you're more realistic and look at 10G or 25G. (Or just buy a pile of used 100G CWDM4 transceivers off eBay.)

(There are goblins in that fairyland, but the real problem is the overall worldview/perspective.)

Same reason Netflix had massively reduced video piracy, and that piracy being back nowadays.

AFAIK, putting the currency symbol in front of the number is actually more rare. Most cultures treat it like any other unit of measurement.

In this case, you could theoretically argue about being cruel to the human operator behind, but that's quite a bit of a stretch. They gave billing access to a poorly controlled machine.