[time-nuts] WWVB remodulator for the Spectracom 8170...

[paul swed]

Exactly as Bob says. Though at the time I built the costas loop I did not
build the remodulator. Just time. Pun intended.
But indeed they add together for those that need both time and frequency.
If you just want time the remodulator is far far simpler.
Regards
Paul
WB8TSL


On Mon, Jun 17, 2013 at 6:11 PM, Bob Camp <lists at rtty.us> wrote:

> Hi
>
> The Costas loop already has the AM component available. There's no need
> for a second receiver, just wire the AM output over to the output modulator.
>
> Bob
>
> On Jun 17, 2013, at 5:57 PM, "David I. Emery" <die at dieconsulting.com>
> wrote:
>
> > On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote:
> >> Chris,
> >>
> >> The 8170 was originally intended to be a frequency reference source
> >> tied to the USFS (United Stated Frequency Standard).  It also gave
> >> the time of day, but I believe that wasn't it's primary purpose.  As
> >> I recall, there were some versions that did not have the clock
> >> readout and some that had a chart recorder.  Back in the 80's I used
> >> to drool (it was a disgusting sight!) over the Spectracom receivers
> >> with the chart recorders.  At that time I was usuing a Gertsch RLF-1
> >> with an external Moseley 680 chart recorder.  The remodulator
> >> precludes it from being used as a frequency standard, but in my
> >> opinion, so does the fact that WWVB is now phase shifted a bunch.
> >>
> >> The 8170 uses a coherent detector and that's where the problem
> >> lies.  While the 8170 still locks to the WWVB carrier, the new BPSK
> >> scheme causes the detector to output bad data in spite of the
> >> original dips in the carrier still being present.  I had always
> >> wondered how it was able to pull the data out the noise, but never
> >> had a manual until just recently.  I had naively assumed that the
> >> WWVB new BPSK scheme would not affect the time of day aspect of the
> >> 8170.  Like I said, I only use it as a clock in my shoppe, and being
> >> an old dog I don't easily learn new tricks such as looking in a
> >> different direction for one of the other clocks.
> >
> >       I suppose I am stating the obvious, but why not combine Paul
> > Swed's Costas loop and this scheme to output a phase locked 60 Khz
> > with the right AM modulation ?
> >
> >
> >
> > --
> >  Dave Emery N1PRE/AE, die at dieconsulting.com  DIE Consulting, Weston,
> Mass 02493
> > "An empty zombie mind with a forlorn barely readable weatherbeaten
> > 'For Rent' sign still vainly flapping outside on the weed encrusted pole
> - in
> > celebration of what could have been, but wasn't and is not to be now
> either."
> >
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