[time-nuts] Dephasing WWVB

[paul swed]

Many of the old receivers use them spectracoms come to mind. They are big
units and +- 40 Hz BW and I am totally unaware that they can be found
today. That also goes for nice transformers and inductors to build higher Q
circuits.
I built a opamp chain and it worked well but those crazy amps do draw
power. I like the ua consumption level. But thats a personnel preference.

I used the 60 KHz watch Xtals and its in the schematics of the WWVB rcvr I
released to time-nuts a year ago. These little crystals are interesting to
work with and available from China 25 xtals for a few $ at the pay site. I
purchased 2 packs so that I could sift through them. The trick is to very
very lightly load them. I could learn much more about them actually. They
seem useful overall.
The first re-modulator used them directly as the 60 KHz source. I stepped
up to the 15.360 MHz osc only because I believed they were not accurate
enough and that turned out not to be the case as I found.

The other comment to note is that these xtals cause an actual signal gap at
the phase transition. Because at that point the signal is actually 2 X 60
Khz. The crystal gaps for at least 8 cycles from what I have seen.
Regards
Paul
WB8TSL




On Sun, Jun 29, 2014 at 6:39 PM, Martin VE3OAT <ve3oat at storm.ca> wrote:

> John Reed wrote :
>
> >
> > By the way, my 5 section synchronous filter is an LC with
> > op-amps between each stage to bring the gain up for the
> > squaring chip.  It has a 2 KHz -6 dB bandwidth at 60 KHz.
> >
>
> John, have you thought of using a single 60.0 kHz crystal as a bandpass
> filter?
>
> I can't remember which receiver it was, but I think one of the old
> commercial WWVB receivers used a crystal as the tuning element.
>
> ... Martin   VE3OAT
>
>
>
>
>
>
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