Classic Electronic Restoration, Vacuum Tube Audio, Technical History, Photography

The HewlettโPackard Z3815A is a GPSโdisciplined frequency reference originally designed for telecomโgrade timing applications, but today it has become a prized instrument among precisionโtiming hobbyists, metrology labs, and the broader timeโnuts community. At its core, the Z3815A combines a highโstability E1938A โhockeyโpuckโ ovenโcontrolled crystal oscillator (OCXO) with a robust GPS receiver subsystem, allowing it to…

Originally posted in November, 2016. I recently acquired two HP/Symmetricom Z3805A GPS Disciplined Oscillator receiver/clocks. These units seem to have several different configurations both inside the box and of the box itself, but all appear to have: Inside the box, I have seen reports of: The box itself can be Samsung rack mount or HP benchtop.…