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

paul swed paulswedb at gmail.com
Sun Nov 22 15:47:26 UTC 2015


As mentioned a nice answer to the wwvb modulation change.
I looked up the parts and it seems that they have gone into the NOS state.
Though you can get some from digikey and such especially in the SOIC
package. Also the VCO isn't available.
It appears that the Chinese sight has the lmc6484 and LM387n at reasonable
prices for small quantities. Most likely will order from there.
Have not checked out the PIC chip yet.
The 74HCXX are common and reasonable.
Regards
Paul
WB8TSL

On Sat, Nov 21, 2015 at 10:40 AM, Rob Sherwood. <rob at nc0b.com> wrote:

> 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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