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

Rob Sherwood. rob at nc0b.com
Sat Nov 21 10:40:44 EST 2015


This circuit can cope with the phase modulated time data and still provide a frequency tracking signal for timebase adjustments?   My Symmetrical WWVB receiver is useless now.  I had to go to GPSDO to validate the operation of my two rubidiums.  Rob, NC0B 

Sent from my iPad

> On Nov 20, 2015, at 7:00 PM, "Tim Shoppa" <tshoppa at gmail.com> wrote:
> 
> 
> 
> Nov/Dec 2015 QEX has KD2BD's WWVB-based standard and decoder nicely written
> up.
> 
> 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
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