Forrest Christian (List Account) wrote:
There are lots of ways to improve a GPS-based NTP server. Better antenna positioning. Better GPS chipset. Paying attention to antenna patterns. Adding notch filters to the GPS feed. And so on.
They are not a very meaningful improvement.
But, in the end, there is nothing better than adding a second GPS source at a diverse location as far as improving reliability, provided that's an option based on timing needs.
You keep ignoring DOS attacks. Though you wrote: : If I just want to deny you time, it gets cheaper and : easier. All I need is a 1.2 GHz oscillator coupled to an : antenna. There are units like this available for under $10, : delivered. These block GPS trackers on trucks and/or private : automobiles. Build your own and you can get a watt or two : to shove into a tiny antenna for not a lot more. Guaranteed : to Jam anything within a couple of blocks. you don't understand similar effectiveness by DOS.
I can also attest that there is at least one overlap between time-nuts and NANOG....
See above. Masataka Ohta