The most accurate nixie clock

The most accurate Nixie Tube clock and 'Scope clock

Accurate 'Scope Clock

The special 'scope clock that I bought from David Forbes (Cathode Corner) has a 1 PPS BNC input on the rear. Without this input the clock, like most clocks, is driven by an internal quartz oscillator. The 1 PPS feature allows the clock to be driven by a more accurate time source such as a WWVB radio clock, a GPS satellite receiver, or an atomic clock.

The 'scope clock below is driven by the 1 PPS output of an Agilent 5071A/001 Primary Frequency Standard (cesium atomic clock). This one is accurate to a few nanoseconds a day.

Here, the 'scope clock is driven directly by the 1 PPS output of a KVARZ CH1-75 Active Hydrogen Maser. The stability of this maser is around 4x10^-15 at 1 day making this the most accurate 'scope clock on the planet.

Accurate Nixie Tube Clock

My best looking Nixie clock is the Commemorative Nixie Tube Clock made by Jeff Thomas (Nixie Tube Digital Clocks and Nixie Wristwatch). This clock, like many desk clocks, derives its timekeeping from the 60 Hz power line.

To drive this nixie clock from an atomic frequency standard I locked a synthesizer to the 5 MHz output of the atomic standard, set the synthesizer to generate a low-level 60 Hz sine wave (and I mean, 60.000000000000 Hz), and then amplified the signal with a bipolar DC power supply to generate a high voltage "mains".

The nixie clock below is powered by a 60 Hz mains generated by a HP 6827A bipolar power supply from a HP 3325B synthesizer from a FTS/Datum 4065B/001 cesium standard. This one is accurate to a few nanoseconds a day.

Here, the Nixie clock is driven by a KVARZ CH1-75 Active Hydrogen Maser (5 MHz) through a HP 3325B synthesizer (60 Hz) through a HP 6827A bipolar power supply (100 VAC) to generate a 60 Hz mains. The accuracy of the Nixie clock is thus locked to the accuracy of the hydrogen maser. The stability of this maser is around 4x10^-15 at 1 day making this the most accurate Nixie clock on the planet. The 'scope clock in the right is directly driven by the maser's 1 PPS output.