Bring up and learn about Calnex GPSDO

[geerlingguy]

Through a happy chance, I'm able to use a Calnex CN-HW-PX-OPT132 as a very stable external GPSDO (GPS Disciplined Oscillator).

With a GPS lock, it has:

Output Frequency Accuracy/Stability:

• 12 mins warm-up time @ 25°C: 5E-10 for frequency stability
• 24 hrs warm-up time @ 25°C and GPS locked: 1E-12, typical (requires a stable temperature
  of ±1°C)

Output time accuracy/stability:

• 24 hrs warm-up time @ 25°C and GPS locked: <50ns (requires a stable temperature of ±1°C)

But using its internal Rubidium oscillator, even if GPS goes away, you get:

Output Frequency Accuracy/Stability:

• 12 mins warm-up time @ 25°C: 5E-10 for frequency stability
• 24 hrs warm-up time @ 25°C and Holdover (lost GPS): <3E-11/month (requires a stable
  temperature of ±2oC)

Output Time Accuracy/Stability:

• 24 hrs warm-up time @ 25°C and Holdover (lost GPS): <2µs/48hr or <1µs/24hr (requires a stable
  temperature of ±2°C)

Unfortunately my existing HVAC is probably not going to guarantee ±1°C, but I could probably hit 2°C...

[geerlingguy]

I first need to find a suitable power supply. The plug looks like a MIDI connector (but is probably 8 pin DIN), but with a screw-in surround, and it's labeled 12V / 8A. Otherwise, on the back it has an SMA GPS Antenna Input.

(Edit: I've submitted the contact form on Calnex's website, for now.)

[geerlingguy]

Just a brief update, I bought a power supply off eBay (Elpac AC Adapter Power Supply, FWB100012A). I had it running for a few hours and it's a little loud (so probably need to find a nice way to set it up in a space outside the studio, maybe in the rack room), and it got a stable GPS lock and disciplined the Rb oscillator. Nice!