Support calibrating from 60 kHz WWVB time signal? (or 72 MHz Primex FM rebroadcasts)

[rxseger]

From the original website:

There are other ways to calibrate these devices -- the FA-SY 1 documentation discusses using the WWVB time signals.

More details at https://en.wikipedia.org/wiki/WWVB

The 70 kW ERP signal transmitted from WWVB is a continuous 60 kHz carrier wave, the frequency of which is derived from a set of atomic clocks located at the transmitter site, yielding a frequency uncertainty of less than 1 part in 10^12

60 kHz may require downconverters for use with common SDR hardware, but could be interesting to support it anyways, as an alternative to the GSM FCCH signal

[rxseger]

Or is it possible to use https://en.wikipedia.org/wiki/WWV_(radio_station) instead? Transmits on 2.5, 5, 10, 15, 20 MHz, I can copy at least the 10 MHz station with my HackRF

[rxseger]

WWVB is often locally rebroadcast at ~72 MHz by various locations, I received 72.320 MHz: https://soundcloud.com/user-223812058/72320-mhz-fm - Primex Wireless clock systems: https://web.archive.org/web/20120907065211/http://www.primexwireless.com/uploads/files/GPSTime.pdf - well within the range of the HackRF.