[time-nuts] Re: Syncserver S300 LFR 60 kHz WVVB

[Todd Smith]

Bob,

It is the correct LFR antenna that was installed when the unit was new.
The antenna is a flat disk that is currently pointing toward Fort Collins,
CO.

Todd

On Sat, Sep 3, 2022, 14:36 Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> One as yet unasked question:
>
> What sort of antenna are you using to feed WWVB into the device?
> Is it the one that Symmetricom used? In the past, I’ve had way more
> trouble locating correct antennas than finding this or that WWVB
> based device ….. On some devices much of the receiver was in the
> antenna. There are a number of older GPS based devices with the
> same sort of issues.
>
> Bob
>
> > On Sep 3, 2022, at 5:23 AM, Todd Smith via time-nuts <
> time-nuts at lists.febo.com> wrote:
> >
> > I am away from the unit for the holiday but the only picture that I have
> at
> > the moment is this one which shows the Multi tech modem attached to it.
> > The board contains the LFR and a spot for an optional modem.  It is
> > connected to the main system board by a multipin ribbon cable.  Given
> that
> > the system board contains a Intel Atom N2700, this connection might be
> > RS232.
> >
> > I will try to get a better picture on Tuesday but there is very little
> > circuitry on this daughter card except for the modem.  I guess there
> > doesn't take much to decode WVVB.  I think I remember just 1 IC and
> several
> > resistors.
> >
> > Todd
> >
> > On Fri, Sep 2, 2022, 18:02 Graham / KE9H <ke9h.graham at gmail.com> wrote:
> >
> >> Todd:
> >>
> >> What does the interface between the WWVB receiver and the rest of the
> unit
> >> look like?
> >> What timing accuracy did they spec when running off the WWVB receiver
> >> (back when it worked?
> >>
> >> --- Graham
> >>
> >> On Fri, Sep 2, 2022 at 2:40 PM Todd Smith via time-nuts <
> >> time-nuts at lists.febo.com> wrote:
> >>
> >>> I inherited these two units at work and they haven't been looked at
> for a
> >>> long time since they just work.  I ordered two replacement M12M
> receivers
> >>> from Jackson Labs to deal with the GPS rollover coming up in Sept for
> >>> these
> >>> units.
> >>>
> >>> I was looking at the modem logs and it looks like the USNO modem line
> in
> >>> DC
> >>> is down.  It rings but doesn't pick up.  I didn't see a way to report
> that
> >>> from the website.  I updated the numbers to NIST and to the working
> USNO
> >>> number in CO.
> >>>
> >>> The LFR and GPS antenna are already run and are working.  I know that I
> >>> can
> >>> use GPS but I wanted to have all timing options running for backups or
> to
> >>> protect from GPS failure or spoofing.
> >>>
> >>> I would very much like to see what options are available to either
> modify
> >>> the existing LFR board or put something in front of it that can send it
> >>> the
> >>> correct 60kHz signal.
> >>>
> >>> I know that it is not necessary but I like things working on my watch.
> >>>
> >>> Thanks for your help.
> >>> Todd
> >>>
> >>> On Fri, Sep 2, 2022, 14:20 <rodger_adams at yahoo.com> wrote:
> >>>
> >>>> Hey Todd,
> >>>>
> >>>> I think you are probably correct that your issue is caused by the BPSK
> >>>> modulation.  There are at least 2 members of this list that have
> worked
> >>> on
> >>>> solutions to the BPSK removal problem.  Paul Swed created a nice
> >>> solution
> >>>> and he and I are currently running this "d-psk-r" circuit and are
> using
> >>> the
> >>>> "corrected" WWVB signal to drive various old WWVB devices, including
> >>> HP-117
> >>>> phase comparator, Fluke 207 comparator, various Spectracom
> comparators,
> >>>> Spectracom Netclocks, R-1407/URQ comparator, and probably a few more.
> >>>>
> >>>> The d-psk-r that we are running uses an Arduino to generate the 1pps
> >>> bpsk
> >>>> code and then a simple mixer (phase flipper) to process the received
> >>> signal
> >>>> directly at 60 khz.  Of course the Arduino circuit needs to be in sync
> >>> with
> >>>> the WWVB phase modulation so we use a GPS module to get the time and
> >>> clock
> >>>> the Arduino using the GPS's PPS output.  It might seem like cheating
> to
> >>> use
> >>>> GPS to correct the WWVB BPSK but if the goal is to return vintage
> >>> hardware
> >>>> to operation it's a pretty good way to go and works very well.  One
> >>> d-psk-r
> >>>> can drive all the 60 khz devices you want.   If you want to eliminate
> >>> the
> >>>> GPS cheat, there are other ways to go.  I've created a module that can
> >>>> drive
> >>>> the d-psk-r Arduino using a WWVB clock module emulating GPS NMEA
> >>> sentences
> >>>> and PPS pulses.  There are also some other circuits floating around
> >>>> including a Costas loop demodulator but I didn't have much luck with
> >>> that.
> >>>> I'm not aware of any commercially available product to solve the
> >>> problem.
> >>>>
> >>>> If you search the group archives you'll find lots of discussions on
> the
> >>>> topic.  If you're not afraid to play around with Arduinos and
> soldering
> >>>> irons, you can build the d-psk-r easily for under $100.  We've written
> >>> up
> >>>> some pretty reasonable documentation which we're happy to share if
> >>> you're
> >>>> interested.
> >>>>
> >>>> I know that Paul and I are still currently using (and to some extent
> >>>> improving) his d-psk-r.  I'd be very interested to learn if there are
> >>> other
> >>>> list members using any other solution(s) or if anyone even thinks it's
> >>>> still
> >>>> a topic worth pursuing.
> >>>>
> >>>> Good luck,
> >>>>
> >>>> Rodger
> >>>>
> >>>> -----Original Message-----
> >>>> From: Todd Smith via time-nuts <time-nuts at lists.febo.com>
> >>>> Sent: Friday, September 2, 2022 11:49 AM
> >>>> To: time-nuts at lists.febo.com
> >>>> Cc: Todd Smith <tssmith2002 at gmail.com>
> >>>> Subject: [time-nuts] Syncserver S300 LFR 60 kHz WVVB
> >>>>
> >>>> Hello
> >>>>
> >>>>
> >>>>
> >>>> I stumbled upon this list while looking for some information to
> refurb a
> >>>> couple of older Symmetricom (Microsemi) S300 Syncserver NTP appliances
> >>>> equipped with the optional LFR 60 kHz kit.  I believe that I am
> >>> receiving
> >>>> signal at my location since the LED on the back of the unit beside the
> >>> LFR
> >>>> antenna  port blinks while it is running.  It shows unlocked in the
> GUI
> >>>> since it is apparently not decoding the signal.
> >>>>
> >>>>
> >>>>
> >>>> I have read where in 2012, NIST changed the format for WVVB from AM
> to a
> >>>> phase modulation and some receivers might not be able to decode the
> >>> phase
> >>>> modulation.  Do you think that is the case here?  I need to get
> another
> >>>> WVVB
> >>>> receiver and test that I can receive signal at this location but I am
> >>> high
> >>>> enough and away from interference sources so that leads me to believe
> >>> that
> >>>> I
> >>>> am probably receiving signal.  Over 72 hours on the graph in the GUI
> >>> and it
> >>>> never decodes a signal yet the back blinks the entire time.
> >>>>
> >>>>
> >>>>
> >>>> If phase modulation is the issue; is there a demodulator that I can
> get
> >>> to
> >>>> correct the signal format?
> >>>>
> >>>>
> >>>>
> >>>> Thank you for your time
> >>>>
> >>>> Todd Smith
> >>>> _______________________________________________
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> send
> >>> an
> >>>> email to time-nuts-leave at lists.febo.com
> >>>>
> >>>>
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> >>
> >
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