What will you do with all those atomic clocks if WWVB goes silent? We’ve got hacks!
There is a lot of buzz about the possible closure of erstwhile NIST time stations, WWV, WWVH and WWVB. For many of us, WWV was one of the first stations we heard on our Zenith Transoceanics at the dawn of our interest in the essential avocation that is amateur radio. As a number of hams sign on to a petition campaign asking for continued funding, others are thinking up ways to continue to provide signals to help set the thousands of devices that depend on the WWVB digital signals for synchronization. Here are some solutions:
A Raspberry Pi Zero WWVB time code generator – Hackaday reports that Pi enthusiast Henner Zeller “manages to coax it into generating 77500.003Hz on a GPIO pin – close enough to the 77.5kHz carrier that DCF77 uses. The signal is AM, and transmits one bit/s, repeating every minute. A second GPIO performs the required attenuation, and a few loops of wire are sufficient for an antenna which only needs to work over a few inches. The Raspberry Pi syncs with NTP Stratum 1 servers, which gives the system time an accuracy of about ±50ms. The whole thing sits in a slick 3D printed case, which provides a stand for the watch to rest on at night; this means that every morning it’s synchronised and ready to go.”
A Raspberry Pi WWVB time code generator – Author Anton Poluektov, says, “This project uses Raspberry Pi to mimic the WWVB signal: it could be useful in cases when real WWVB signal is too weak or cannot be received. For instance, I use Raspberry Pi to set correct time of my Casio WaveCeptor watch desined for US market (that can only receive WWVB signals) outside of US.” If you’re an Arduino Nano fan, this one may be for you.
A One Component WWVB time code generator – @sbmull at Instructables.com shares this single chip solution, featuring an attiny45 microcontroller. Here’s another github repository that works with the same controller.
If you’re into etching your own circuit boards… Anish Athalye built a pretty cool solution from scratch.
There’s even an iPhone app that mimics the WWVB audio signal – The folks at ZenRhen say, “Clock Wave allows you calibrate radio controlled watch or clock anytime and anywhere. Just click ‘Transmit’ button, set your watch or clock to manual receive time signal, and place it nearby your iPhone/iPad’s speaker, it will be calibrated in a few minutes.” How does it work? According to JR Computing, the app “generates 20KHz audio signals with 0.2, 0.5 and 0.8 second bursts. Since that signal is square wave, the 3rd harmonic 60kHz (20k x 3) electro-magnetic signal is also emitted from the earphone as a close representation the radio broadcast waveform.” It’s $1.99 at the app store.
Got other solutions? Email links to W9WSW (at) arrl (dot) net!