I’ve seen them for $80 on eBay, and you could build something like that yourself with a $25 thin client[0] and a USB GPS dongle. But I doubt you’d have the local oscillator for hold over, you wouldn’t have the 10MHz and 1PPS inputs and outputs, and let’s not forget the lack of a cool looking case with VFD. :-)
I have no need for an NTP server, this was just a fun deep dive into something I found at the electronics flea market. But there must be reasons why these things still go for much more than $80 on eBay after they’ve been upgraded with a new GPS module.
Even the most basic Symmetricom (microchip now?) and ptf units have all the options you need to survive an outage and configure the thing anyway you want. I've got a busted Symmetricom that won't see anything in the sky but still provides NTP and IRIG-B using a calibrated Rubidium source for its reference clock. I don't need the time to be accurate but I need it to be precise.
I have no need for an NTP server, this was just a fun deep dive into something I found at the electronics flea market. But there must be reasons why these things still go for much more than $80 on eBay after they’ve been upgraded with a new GPS module.
[0] https://tomverbeure.github.io/2023/06/25/ThinMachine-a-Thin-...