[time-nuts] WWVB remodulator for the Spectracom 8170...
Burt I. Weiner
biwa at att.net
Mon Jun 17 13:56:17 EDT 2013
Chris,
I think Paul really came up with an elegant answer. As you well
know, the problem with the new format and phase locked receivers is
that WWVB's phase is now being shifted for the new encoding
scheme. It's this phase shifting that's messing up the phase locked
receivers like the Spectracom 8170. Part of Paul's circuit generates
a new 60 kHz signal that's not phase shifted. The receiver portion
of his circuit decodes the dips that WWVB still transmits, and
outputs the data which is used to turn on and off a "switch" that
drops the new 60 kHz signal by approximately 14 dB in sync with the
WWVB dips. I'm going to build this circuit, but I'm planning on
using the receive module out of one of the many "Atomic Clocks" that
I have around. I guess you could ask, Why don't I just put the
Atomic clock on the wall in my shoppe and forget about the 8170? An
honest answer to that is, that's no fun.
In a sense you could say that Paul's circuit does get the WWVB signal
to the receiver - it's just a new phase stable version of the signal
signal. This way I don't have to mess with the insides of the 8170.
Burt, K6OQK
>From: Chris Albertson <albertson.chris at gmail.com>
>
> <time-nuts at febo.com>
>Subject: Re: [time-nuts] WWVB remodulator for the spectracom 8170 the
>
>
>I'm looking at the schematic. I thought the goal was to get the 60KHz
>signal from WWVB to the HP unit. This schematic sends an approximatly
>60KHz signal from the tuning fork to the HP. but copies the AM modulation
>from WWVB. So the 8170 does not look at the 60KHz carrier? and only cars
>about the time code?
>
>Maybe another way then is to bypasss the radio inside the 8170 and just
>send the demodulated logic bit
>
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
biwa at att.net
www.biwa.cc
K6OQK
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