Shaun Merrigan
Classic Electronic Restoration, Vacuum Tube Audio, Technical History, Photography
Category: Time and Frequency
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The Hewlett‑Packard Z3815A is a GPS‑disciplined frequency reference originally designed for telecom‑grade timing applications, but today it has become a prized instrument among precision‑timing hobbyists, metrology labs, and the broader time‑nuts community. At its core, the Z3815A combines a high‑stability E1938A “hockey‑puck” oven‑controlled crystal oscillator (OCXO) with a robust GPS receiver subsystem, allowing it to…
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Originally posted in February, 2017 Numitrons are low voltage incandescent display devices perfected and marketed by RCA (see RCA advert above) in the early 1970’s. I would call this a bridge technology as the display is incandescent, but can be driven by integrated circuits. They were quickly displaced by solid state LED (light emitting diode)…
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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.…