PCs, NTP and FR24 receivers
While most PC clocks may not be highly accurate:
a) all of the PCs in my house are synchronised to NTP (I have my own NTP server)
b) most FR24 receivers are dedicated boxes - typically Raspberry Pi with an RTL dongle and *are* synchronised to NTP. Why dedicated boxes? because we leave them switched on 24/7/365.
G