Measuring the doppler shift of WWVB during a flight

https://greatscottgadgets.com/2025/10-31-receiving-wwvb-with-hackrf-pro/

#HackerNews #Measuring #Doppler #Shift #WWVB #Flight #HackRF #Gadgets

Developing HackRF Pro (in production now!) has been a lot of work, but I've been able to have some fun along the way.

Receiving #WWVB with #HackRF Pro: https://greatscottgadgets.com/2025/10-31-receiving-wwvb-with-hackrf-pro/

Just made sure that my Python WWVB decoder would reject an AM timecode with hour 24 (the hypothetical "leap hour") as invalid, among several other kinds of invalid data (bad BCD encoding & unexpected MARK symbols) https://github.com/jepler/wwvbpy/blob/main/test/testwwvb.py#L406

#python #WWVB

For North America folks interested in low-maintenance, accurate atomic/radio clocks, but live outside the expected WWVB range¹ :

The La Crosse UltrAtomic large wall clock has a semi-novel internal two-antenna design that allows the WWVB signal to be picked up at greater distances (such as southcentral Alaska) when conditions are favorable (especially at night).

And since the modern WWVB signal² embeds DST/ leap seconds / etc well in advance of actual changes, and since the oscillator is relatively low drift ... the time accuracy window is pretty robust.

It takes either two or four D batteries. Four will get you around four years of life in ANC (in my experience).

So between the self-setting and the long battery life .... you can put a visible, affordable, low-maintenance clock in a hard-to-reach place, even in Alaska.

And here's a great teardown for the geeks:
http://leapsecond.com/pages/ultratomic/

(not affiliated or compensated, just a fan!)

¹‍https://tf.nist.gov/stations/wwvbcoverage.htm
²‍https://www.nist.gov/publications/wwvb-time-signal-broadcast-new-enhanced-broadcast-format-and-multi-mode-receiver

#WWVB #Alaska #TimeNut