[time-nuts] KD2BD WWVB receiver/decoder in QEX

Tim Shoppa tshoppa at gmail.com
Fri Nov 20 18:29:45 EST 2015

Nov/Dec 2015 QEX has KD2BD's WWVB-based standard and decoder nicely written

His decoder has BPSK demodulation capability, BPSK output is available but
for the most part it detects the BPSK only to then remove BPSK prior to
carrier phase tracking.

Starts with a tuned loop antenna colocated with a 40dB preamp, then a bunch
of analog circuitry consisting of discrete NPN's, CMOS SPDT switches and
op-amps, 0.025Hz low-pass filter, disciplining a 10MHz TCXO. There is some
digital logic (HC390's) to divide the 10MHz TCXO down and produce various
standard frequencies, as well as a PIC to decode and display the WWVB time
code. Baseband WWVB signals are used to modulate a 1kHz audio tone for
aural monitoring.

Recommended reading!!! Also there is KD2BD's web description of the same
receiver as applied to FMT's: http://www.qsl.net/kd2bd/fmt-methodology.html

Tim N3QE

More information about the time-nuts mailing list