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, [email protected] 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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