Operations
What holdover means when GNSS drops for a short time
After unlock, time drifts. Drift depends on the oscillator and outage length—do not promise unlock-period accuracy with lock-state figures.
LOCK means GNSS discipline is active. After unlock, the unit enters holdover: the clock free-runs on the oscillator and slowly walks away from UTC.
Short blockage (antenna covered, storm) and long outages (cut coax) are different ops problems—separate alarms from acceptance criteria.
TCXO and OCXO holdover differ. Use the datasheet and ordered SKU; do not verbally promise “nanoseconds for N hours unlocked”.
NTP clients may keep syncing to a drifting server after unlock. Monitor server LOCK state, not only client offset.
After sky view returns, wait for LOCK again before accuracy acceptance. Datasheet figures apply only to the stated channel and lock state.