[time-nuts] WWVB Dephaser Question

[paul swed]

OK then that would be a classic TRF receiver. Very typical be it
transistors and coils or opamps.
Whats the level on the SA?
Now you have entered the nasty territory that can give you many hours of
fun. The nast BPSK signal. Look at google for BPSK and costas loop
techniques. That will give you insights as to what to do. Essentially lock
an oscillator create 2 signals 90 degrees out and mix or sample with those
two signals. The math gets really interesting at that point as how to
detect the phases. For me thats all clear as mud.

On Fri, Oct 9, 2020 at 1:58 PM <rcbuck at atcelectronics.com> wrote:

> Paul, Bob,
>
> I am not using any commercial receiver. I am building everything from
> scratch. The RF front end starts with a ferrite rod antenna feeding a
> differential first op amp followed by 5 stages of op amp filtering and
> amplification. When the last stage is fed to my spectrum analyzer
> (through attenuators) the WWVB signal is clearly visible. I'm now trying
> to figure out how to detect the phase shift so I can get the time data
> for my CPU to process and send to a display.
>
> I already have a GPS based clock that I built so I thought the WWVB
> phase clock would be an interesting project.
>
> Ray
>
> -------- Original Message --------
> Subject: Re: [time-nuts] WWVB Dephaser Question
> From: Bob kb8tq <kb8tq at n1k.org>
> Date: Fri, October 09, 2020 7:35 am
> To: Discussion of precise time and frequency measurement
> <time-nuts at lists.febo.com>
>
> Hi
>
> At least to me, anything dimensioned in the 100’s of feet is
> “massive” compared to
> the rod antennas normally seen in WWVB use ….
>
> The other point being that if the antenna is some sort of large loop,
> it’s going to be
> a good long ways away from the receiver. You get both a larger signal
> voltage and better
> isolation …..
>
> Bob
>
> > On Oct 8, 2020, at 11:30 PM, John C. Westmoreland, P.E. <
> john at westmorelandengineering.com> wrote:
> >
> > Hello All,
> >
> > Are there any design details someplace regarding these massive antennas?
> >
> > Thanks,
> > John
> > AJ6BC
> >
> >
> > On Thu, Oct 8, 2020, 19:27 paul swed <paulswedb at gmail.com> wrote:
> >
> >> Hello to the group.
> >> Ray as Bob mentions you are taking a 10s of uv signal to a logic level
> of
> >> maybe 4V.
> >> If the loop is any place close to the divided down signal, it will
> >> oscillate. It would take incredible shielding to protect the receiver.
> >> Thats why you often see a solution that doubles to 120 KHz and modifies
> the
> >> detectors to work at that frequency. That means hacking the radio
> >> internally. Not fun. The other really annoy effect is that the doubling
> >> slips phace due to noise and propagation. So if charting suddenly you
> get a
> >> 180 degree flip. Thats messy.
> >> The doubling solution can work. Search for carter and there are several
> >> others.
> >> But having tested and used all of the alternates and lots more on the
> east
> >> coast decided they were too much trouble. You should see the box of
> boards
> >> I have chuckle.
> >> For me I am very happy with the d-psk-r. Though in being above board I
> >> designed version 1 and Rodger and I did version 2. Its solid and no
> mods to
> >> any receiver. Everything has always been released to the time-nuts
> group.
> >> As they say have fun.
> >> Regards
> >> Paul.
> >> WB8TSL
> >>
> >> On Thu, Oct 8, 2020 at 5:39 PM <rcbuck at atcelectronics.com> wrote:
> >>
> >>> Bob,
> >>>
> >>> I am using a ferrite rod antenna for the receiver. No outside antenna.
> >>>
> >>> Ray
> >>>
> >>> -------- Original Message --------
> >>> Subject: Re: [time-nuts] WWVB Dephaser Question
> >>> From: Bob kb8tq <kb8tq at n1k.org>
> >>> Date: Thu, October 08, 2020 12:40 pm
> >>> To: Discussion of precise time and frequency measurement
> >>> <time-nuts at lists.febo.com>
> >>>
> >>> Hi
> >>>
> >>> A lot depends on your antenna setup. You can also swamp out the
> incoming
> >>> WWVB signal…….
> >>>
> >>> Bob
> >>>
> >>>> On Oct 8, 2020, at 2:07 PM, <rcbuck at atcelectronics.com> <
> >>> rcbuck at atcelectronics.com> wrote:
> >>>>
> >>>> I have read several different articles where the WWVB phase shift is
> >>>> eliminated by doubling the signal to 120 kHz. Several members of the
> >>>> list have built these units.
> >>>>
> >>>> Assume I build a circuit to double the incoming signal and use a
> >> schmitt
> >>>> trigger to get a 120 kHz square wave. If I then divide that signal
> back
> >>>> down to 60 kHz will that signal be strong enough to swamp out the WWVB
> >>>> signal? I'm guessing it will be since it is at the 5 volt level and
> >>>> somewhere in the +25 dBm or greater range.
> >>>>
> >>>> Ray,
> >>>> AB7HE
> >>>>
> >>>> _______________________________________________
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