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Hi,
?
while monitoring the WSPR signal from my QMX to figure out why I didn't get spotted at all, I found out that the QMX was not sending on the right point of time but shifted by several dozens of seconds.
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I then did some experiments by attaching / disconnecting the GPS module and it seems that the QMX clock will not always be 100% in sync.
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At first glance it seemed that after a disconnect (or signal loss maybe?), the clock of the QMX may jump back to some older point in time.
?
My expectation was that I can sync the QMX via GPS once and then switch of / disconnect the GPS with the QMX clock being still in sync (for the next couple of hours) but apparently this is not the case.
?
When doing these tests, I was entering the beacon menu a couple of times, and finally I found the culprit:
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As soon as the time menu item is being displayed - without entering it for editing!! - the clock of the QMX will be reset to the time just indicated there! Especially that means that the seconds will be reset to zero. It's 100% reproducible with 1.00.20 firmware.
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73, Andreas
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Thanks Andreas
Noted. I will fix it...
73 Hans G0UPL
Hi,
?
while monitoring the WSPR signal from my QMX to figure out why I didn't get spotted at all, I found out that the QMX was not sending on the right point of time but shifted by several dozens of seconds.
?
I then did some experiments by attaching / disconnecting the GPS module and it seems that the QMX clock will not always be 100% in sync.
?
At first glance it seemed that after a disconnect (or signal loss maybe?), the clock of the QMX may jump back to some older point in time.
?
My expectation was that I can sync the QMX via GPS once and then switch of / disconnect the GPS with the QMX clock being still in sync (for the next couple of hours) but apparently this is not the case.
?
When doing these tests, I was entering the beacon menu a couple of times, and finally I found the culprit:
?
As soon as the time menu item is being displayed - without entering it for editing!! - the clock of the QMX will be reset to the time just indicated there! Especially that means that the seconds will be reset to zero. It's 100% reproducible with 1.00.20 firmware.
?
73, Andreas
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Thanks, Hans! And when you are at it, maybe it's also worth to execute GPS time synchronization as soon as a time is being received (if there was not any fix before).
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It's sometimes hard to get a stable fix, but the time will be already accurate when a bunch of satellites is being seen.
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For me, it would be sufficient if this could be done just manually, on request, e.g. within the GPS Viewer by (long)pressing the menu button...
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73, Andreas
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Good idea Andreas. While running wsjtx I also found QMX won't transmit unless the GPS is unplugged. I am not sure if wsjtx can take is timing from the GPS though, that may mean a problem if you have no internet timing.?
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The issue with QMX not transmitting until GPS is unplugged is on my list :-/
There are programs that can synchronize PC time, given a serial data stream from a GPS.?
Someone suggested a little while ago, that it would be nice if QMX could stream the incoming serial data from the GPS serial port, into the USB Serial Virtual COM - that way, temporarily this function could be enabled, in order to let the PC sync its time. Sounds like a nice plan. And it's on my list too...
Good idea Andreas. While running wsjtx I also found QMX won't transmit unless the GPS is unplugged. I am not sure if wsjtx can take is timing from the GPS though, that may mean a problem if you have no internet timing.?
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hi
BktTimeSync?
synchronizes time from internet and QRPLabs QLG1 or QLG2
I run it every once in 10 minutes
73 DE muhsin TA1MHS
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Hi all,
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my initial concerns where about the Beacon mode where the QMX will operate standalone.
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I would also suggest here that the internal clock of the QMX gets a dirty flag which is set to true until the clock was either synchronized via GPS or set manually.
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And while the clock is "dirty" the Beacon mode should not transmit at all, displaying a "clock not synchronized" indicator.
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This will especially prevent the QMX from transmitting right on poweron, when the time starts at 0:00 and the start frame is 0 as well.
?
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But sure - when a computer comes into play, it's already possible to synchronize the computer clock via GPS - just plug the QLG2 to the computer via it's USB interface and use a tool like or ?or the one mentioned by TA1MHS
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No need to connect the QLG2 to the QMX in this case. (But it's still possible of course...)
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73, Andreas
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Hello Andreas
I agree about the "dirty flag". I added it to my list. I will make the beacon truly awesome in the end.? The reason for the streaming facility to send GPS data through the USB Virtual COM Serial port to the PC, is for users of QMX+ who have the internal GPS. These cannot?just unplug the QLG2 and plug it instead via its USB interface to the PC.?
On Wed, Jul 17, 2024 at 2:05?PM Andreas DM7AK via <mail2dm7ak= [email protected]> wrote: Hi all,
?
my initial concerns where about the Beacon mode where the QMX will operate standalone.
?
I would also suggest here that the internal clock of the QMX gets a dirty flag which is set to true until the clock was either synchronized via GPS or set manually.
?
And while the clock is "dirty" the Beacon mode should not transmit at all, displaying a "clock not synchronized" indicator.
?
This will especially prevent the QMX from transmitting right on poweron, when the time starts at 0:00 and the start frame is 0 as well.
?
?
But sure - when a computer comes into play, it's already possible to synchronize the computer clock via GPS - just plug the QLG2 to the computer via it's USB interface and use a tool like or ?or the one mentioned by TA1MHS
?
No need to connect the QLG2 to the QMX in this case. (But it's still possible of course...)
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73, Andreas
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Ok, I see, Hans
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Hopefully that "streaming" feature - in addition to higher load to the QMX cpu causing possible glitches - does not any add delay or even jitter to the signal so that the sync of the PC clock will be flawed...?
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A dedicated USB port on the QMX+ for the QLG2 might be safer...
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73, Andreas
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Hello Andreas
There will be delay, there always is, where USB is involved. But we aren't sending 1pps via the serial port anyway; so in any case, it's an approximate time setting?not high precision. There won't be glitches on the QMX CPU which has a lot of power!?
The PC program reads the serial data and parses it and sets the PC clock. I assume it reads the?$GPRMC sentence, which is not guaranteed by the NMEA 0183 protocol to come first in the list of sentences. If all it does is parse $GPRMC when it arrives, and set the PC clock, that gives rise to inaccuracies.?
If the program is smart it could still sync the time quite accurately (I don't know if it is). Then it would look at the start, the first bytes received over the serial port, which indicate the start of the serial data stream, occur when the 0.1-second duration 1pps pulse finishes. So theoretically the PC program could add 0.9 seconds to that and sync itself. It would be different potentially, for different GPS units since the 0.1 seconds pps duration is most common, but is not universal.?
> A dedicated USB port on the QMX+ for the QLG2 might be safer...?
You mean QLG3, I suppose. Anyway I will add a second Virtual COM Serial port, so this can be used for the GPS data if desired, separate to CAT / Terminal for the rest of QMX; but this will not solve the aforementioned problems.?
In the end, how accurately the PC sets the time from the NMEA data depends on how cleverly the PC time sync program is written. It depends necessarily also on USB latencies which are always there but I would say are a few milliseconds at worst.?
73 Hans G0UPL
On Thu, Jul 18, 2024 at 10:08?AM Andreas DM7AK via <mail2dm7ak= [email protected]> wrote: Ok, I see, Hans
?
Hopefully that "streaming" feature - in addition to higher load to the QMX cpu causing possible glitches - does not any add delay or even jitter to the signal so that the sync of the PC clock will be flawed...?
?
A dedicated USB port on the QMX+ for the QLG2 might be safer...
?
73, Andreas
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Hello all:
My QMX+ with QLG3 GPS does not display the correct time.
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I have the following settings:
- Clock: ON
- GPS Source: QMX+ Internal
- Real Time Clock: QMX+ RTC
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Using PuTTY, looking at the GPS Viewer (under Hardware Tests), the correct date and time is displayed.? When I Toggle Raw Mode, I see all the GPS data repeated on 1 second intervals.
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All looks correct to me, except that the time displayed on the QMX+ screen never updates to the GPS time.
What might I be doing wrong?
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73, KB5QR
Don
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Hi Don,
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do you also have a GPS fix??
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Without GPS fix (2D or 3D), the QMX will not sync the time although the GPS module might be already receiving the time correctly and this will also be displayed within GPS Viewer.
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73, Andreas
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Andreas:
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Thank you!
"Fix" showed "1"; when I relocated the antenna the Fix parameter showed "3D" and the clock now shows the correct time in agreement with the GPS.
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73, KB5QR
Don
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Mild aside, there are dedicated solutions for accurate GPS disciplined time...
I don't think Hans needs to change the hardware just to allow a slightly more accurate use case.
On Thursday, July 18th, 2024 at 12:08 AM, Andreas DM7AK <mail2dm7ak@...> wrote:
Ok, I see, Hans
?
Hopefully that "streaming" feature - in addition to higher load to the QMX cpu causing possible glitches - does not any add delay or even jitter to the signal so that the sync of the PC clock will be flawed...?
?
A dedicated USB port on the QMX+ for the QLG2 might be safer...
?
73, Andreas
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Is there a way to connect the shack clock to the Windows laptop to utilize the bkttimesync?
--
73
Karl
KI4ZUQ
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Hi Don,
?
I observe that the QLG3 appears to synchronize the time only when the Real Time Clock menu option is set to "Software", not "QMX+ RTC"
The Operating Manual makes no mention of this.
While using the hardware Real Time Clock, the QMX+ loses time sync after a few hours, and there is no adjustment to correct for this.
The QLG3 does not appear to correct for the accumulating error in the hardware Real Time Clock.
I suspect that this may also cause the reported corruption and loss of WSPR beacon decodes over time while using the hardware Real Time Clock.
So far, I have not observed this problem while running the WSPR beacon with the Real Time Clock menu option set to "Software."
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73, Carol KP4MD
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On Thu, Jul 18, 2024 at 10:40 AM, KB5QR wrote:
Hello all:
My QMX+ with QLG3 GPS does not display the correct time.
?
I have the following settings:
- Clock: ON
- GPS Source: QMX+ Internal
- Real Time Clock: QMX+ RTC
?
Using PuTTY, looking at the GPS Viewer (under Hardware Tests), the correct date and time is displayed.? When I Toggle Raw Mode, I see all the GPS data repeated on 1 second intervals.
?
All looks correct to me, except that the time displayed on the QMX+ screen never updates to the GPS time.
What might I be doing wrong?
?
73, KB5QR
Don
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Hi Carol
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Thanks for this observation - I have just uploaded the latest SSB firmware, and done a hardware reset. I was wondering why the QMX+ RTC wasn't updating. Setting "software" mode cured it - update manual please, Hans.
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773
Tony, G3OVH
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F4WCV
Karl
Carol KP4MD