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
Hi
Quick summary of WWVB changes:
As time has gone on, the world has fallen in love with switching power
supplies. Often these run at 40 to 80 KHz and create a ton of RFI. That
has made WWVB more difficult to receive. Also MSF propagates into
the northeast at some times creating issues as well.
They went to a phase modulation setup to improve the ability to decode
the signal. It most certainly did that. They kept enough of the old AM
modulation to allow the typical wrist watch to demodulate the signal.
What this did do is to create a signal that lab gear trying to phase lock
to the signal no longer worked.
Just how the problem shows up on this or that piece of gear is very much
a “that depends” sort of thing. Even with the old signal, getting outdoor
antennas set up properly and tracking down issues was a bit of a pain.
Sorting that out on top of phase mod stuff … yikes.
Best guess: the unit is trying to phase lock and it cant.
There is only one outfit that seems to have jumped on the bandwagon
with a chip for the new format. You can get boards that have the chip
on them. They are not going to help much with phase locking. ( and
AM demodulation still should work ….).
Various folks here on the list have done DIY projects to feed an old
style signal into this or that device. There are a variety of practical issues
and decisions to be made if you go that route.
Bob
On Sep 2, 2022, at 7:48 AM, Todd Smith via time-nuts time-nuts@lists.febo.com wrote:
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
time-nuts mailing list -- time-nuts@lists.febo.com
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Todd it is indeed the case. The phase modulation screws up the receivers.
It affected all of the more sophisticated receivers making them somewhat
useless. There are various hacks from somewhat simple to complex. Danger
may require code and a soldering iron. Some of these hacks work very well.
Sounds like a nice unit.
Regards
Paul
WB8TSL
On Fri, Sep 2, 2022 at 11:49 AM Todd Smith via time-nuts <
time-nuts@lists.febo.com> wrote:
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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Todd looking at the spec sheet do you have the gps option also??
If so it should lock I would expect.
On Fri, Sep 2, 2022 at 2:05 PM paul swed paulswedb@gmail.com wrote:
Todd it is indeed the case. The phase modulation screws up the receivers.
It affected all of the more sophisticated receivers making them somewhat
useless. There are various hacks from somewhat simple to complex. Danger
may require code and a soldering iron. Some of these hacks work very well.
Sounds like a nice unit.
Regards
Paul
WB8TSL
On Fri, Sep 2, 2022 at 11:49 AM Todd Smith via time-nuts <
time-nuts@lists.febo.com> wrote:
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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
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@lists.febo.com
Sent: Friday, September 2, 2022 11:49 AM
To: time-nuts@lists.febo.com
Cc: Todd Smith tssmith2002@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
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an
email to time-nuts-leave@lists.febo.com