Re: Observing CW sidebands?
Bogdan,
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If you really want to understand the Si5351, you might want to read this ap note:
It took me several days to fully understand it, that part is rather complicated and the documentation
could be better.
?
Figure 1 of that ap note shows a block diagram of the Si5351, it has two PLL's.
Not shown, each of the two PLL's includes a multisynth divider in the feedback loop that locks the PLL
to some ratio of the crystal oscillator.? The multisynth dividers use a special trick to get very?
accurate fractional divide ratios, the output of each VCO has "almost" not jitter (or spurs).
The VCO's are spec'd to operate between 600 and 900 MHz, but Hans has found
that range can be extended considerably.
?
The device variant we use only has 3 clocks, not the 8 clocks shown in that diagram.? On the QMX,
the output of one VCO gets divided by an integer amount using two of the output multisynth dividers
(which are shown in Figure 1) to drive CLK0 and CLK1 at the same frequency but 90 degrees apart.
This frequency is about 12khz away from the operating frequency so the DSP software has a 12khz
audio signal to process.? The second VCO gets divided by an integer amount to drive CLK2
at exactly the operating frequency for transmit.
?
We don't have Hans' code to inspect, but there are several libraries out there for the Si5351.
They can be a difficult read, as the code tries to do everything anyone could possibly want from the Si5351.
Here's some very simple code that is successfully used by several different radios
including the *Bitx* kits by Ashhar Farhan, VU2ESE, and some of the kits from Steve Weber, KD1JV:
This code uses only one VCO with an integer divide on the VCO multisynth to run the VCO at 875mhz.
It then uses fractional divide ratios on the three output multisynth dividers to generate
independent clocks between 4khz and 109mhz.
?
Jerry, KE7ER
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On Thu, Mar 13, 2025 at 01:28 AM, Bogdan wrote:
I will probably spend a few more hours on this to:
- Try to understand the Si5351 a little more
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Re: Does factory reset on QMX(+) delete the firmware?
FWIW ... There is a manual, force firmware load mode as well. That involves jumpering on the main board for the QMX series units. The unit is then 'seen' as a flash drive on a PC and allows for copying in the firmware file.?
And you have to remember to remove the jumper after powering down otherwise the unit goes into firmware update mode again.?
All detailed in the manuals.
On Thu, Mar 13, 2025 at 10:41 AM, Jerry Gaffke via groups.io <jgaffke@...> wrote: Rob,
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Looks like the QMX and the QMX+ are different.
In the past, all kits arrived without firmware, as you say.
Today the QMX+ kit arrives from the "factory" with the latest firmware already programmed into the processor.
The QMX kit arrives without firmware, the kit builder must install the firmware as you say.
?
My rev2 QMX+ kit arrived with firmware already installed.
I assumed the QMX did too, until I looked into this issue today and found I was wrong.
?
Regardless, "factory reset" only resets the user settings to their defaults,
it does not erase the firmware.? ?Admittedly, that term is a bit imprecise
even to a native English speaker.? Perhaps best to think of it as?
returning the user settings to their original state, as coded into the
firmware that was written at the "factory".
?
Jerry, KE7ER
?
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On Thu, Mar 13, 2025 at 03:25 AM, <ha7rja@...> wrote:
Thank you Jerry!
For a kit, i.e. rig yet to be built, the 'factory state' is without the firmware, hence my question...
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Re: #qmx SSB update - nearly there
#qmx
Hello Patrick
Years ago, when I saw the RTTY to CW translation in KX2 etc I thought that was a pretty neat idea and thought I'd put it in QSX. So yes, why not, we should have it in QMX/QMX+! But not today.
On Thu, Mar 13, 2025 at 5:29?PM Patrick Sullivan via <expatrick= [email protected]> wrote: Hans and Dave - who have both brought me so much radio pleasure- what would it take to build more digital mode decoding and transmit KX2 style into QMX? Once SSB tx is available, would it be possible to add native PSK31 tx/rx with CW translated to PSK31, RTYY /or other modes?
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73 de AC3K
?
?
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Re: QMX CW keyer & message memory glitch
Murphy's Law of POTA.
Here's what the manual has to say:
?
The message can be transmitted multiple times according to the “Repeats” parameter in the
Messages menu (see later description). The interval between the repeated transmissions is also
defined in the Messages menu, in the “Interval” parameter.
Once you have selected the message that you want to transmit, press one of the three buttons as
follows:
? REPEAT: Transmit the message repeatedly by pressing the “Select” button
? ONCE: Transmit the message only once by pressing the “TUNE” knob button
? CANCEL: Cancel the messages operation by pressing the “Exit” button
When REPEAT message transmission mode is activated, the number of repeats and the interval
between repeats is as specified by the Repeats and Interval parameters in the Messages menu.
The stored message transmission is sent at the currently defined keyer speed.
During the actual stored message transmission, you can immediately cancel the transmission at
any time by pressing the “Exit” button or by keying the transmitter with the Morse key or paddle if
you are using one.
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And later (suggestion to Hans - please put this information all in one place):
?
The Repeats parameter specifies how many times the message transmission will be repeated, in
the repeat transmission mode. The Repeat parameter is a number from 0 to 99; in the case it is
set to zero, the Message transmission continues indefinitely.
?
Seems like you have Repeats set to 0.
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73, Mike KK7ER
?
?
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Re: Does factory reset on QMX(+) delete the firmware?
Rob,
?
Looks like the QMX and the QMX+ are different.
In the past, all kits arrived without firmware, as you say.
Today the QMX+ kit arrives from the "factory" with the latest firmware already programmed into the processor.
The QMX kit arrives without firmware, the kit builder must install the firmware as you say.
?
My rev2 QMX+ kit arrived with firmware already installed.
I assumed the QMX did too, until I looked into this issue today and found I was wrong.
?
Regardless, "factory reset" only resets the user settings to their defaults,
it does not erase the firmware.? ?Admittedly, that term is a bit imprecise
even to a native English speaker.? Perhaps best to think of it as?
returning the user settings to their original state, as coded into the
firmware that was written at the "factory".
?
Jerry, KE7ER
?
?
On Thu, Mar 13, 2025 at 03:25 AM, <ha7rja@...> wrote:
Thank you Jerry!
For a kit, i.e. rig yet to be built, the 'factory state' is without the firmware, hence my question...
|
Re: #qmx SSB update - nearly there
#qmx
Hans and Dave - who have both brought me so much radio pleasure- what would it take to build more digital mode decoding and transmit KX2 style into QMX? Once SSB tx is available, would it be possible to add native PSK31 tx/rx with CW translated to PSK31, RTYY /or other modes?
?
73 de AC3K
?
?
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Re: Fab House Factory Video
Thanks for posting this link.? A very interesting tour!
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Re: Basic building questions (solder, etc.)
#QMXplus
A small tin of rosin soldering flux is very handy.? At the very least, get a small roll of de-soldering braid for when you need to un-do a solder joint.? A solder-sucking device of some sort is very handy, too.? You'll need a way to keep your soldering iron tip clean, a natural sponge at least, a metal 'pot scrubber' device is very handy, too.
?
I bought a very cheap (probably in the $20 range) digital microscope and it was of such low quality that it was not suitable at all.? The working distance was on the order of 1inch, the magnification was so powerful that I had problems actually finding what I wanted to view, and the resolution was so low that really examining an item was not even possible.? Harbor Freight has a very nice multi-power, lighted, magnifying visor that is very reasonably priced and has a decent working distance at the low magnification setting - this is probably the best value.? I also bought an Amscope binocular 'inspection' microscope and I am VERY happy with it!? The working distance is on the order of 9" +/-, the magnification is reasonable and I find watching a solder joint form fascinating.? Kinda pricey, though - a bit under $200 a few yrs ago, probably in the $250 range now.
?
You'll need fine tip needle nose pliers and a flush cut diagonal cutter, too.? Be sure to get the SMALL ones of these, that are suitable for the 'fine' small scale work you'll be doing - not the larger ones more suitable to automotive or house-wiring work.
?
Given the choice of 9V or 12V, I'd go with 12V just to keep all of my low voltage devices the same, so I won't 'blow up' a 9V device or wonder why a 12V device just won't work well at all connected to the 'wrong' power supply.
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Good luck!! and most of all have FUN building your new radio and even MORE fun radio-ing with it.
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Re: PIN diode bias current unstable
#qmx
6C would be correct. ?It’s one of the hfe spec variants if the BJT
--
73
Jeff Moore
W1NC
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Re: Does factory reset on QMX(+) delete the firmware?
Thank you Jerry!
For a kit, i.e. rig yet to be built, the 'factory state' is without the firmware, hence my question...
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Re: PIN diode bias current unstable
#qmx
There's a total of 5 BC817s on the QMX+, one on each of the three SMPSs and two on the PA power modulator.? Are the other ones OK?? And would the assembly process use BC817s all from one reel for everywhere?
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Chris, G5CTH
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Re: Observing CW sidebands?
Thank you Hans, Jerry.?
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Indeed, this is now purely an intellectual exercise.
Based on what you have said, it is clear this subtle effect is due to parasitic effects and not related to how the CW is generated.
?
I will probably spend a few more hours on this to:
- Try to understand the Si5351 a little more
- Experiment with different power supplies
- Re-check a few more frequencies / bands and re-confirm if the offset and amplitude changes or remains the same.
I will revert in due course with a summary table of the results for anyone who might be interested.
?
Thank you Jerry for the suggestion about the 100 Hz on the Yaesu, that might be it!
?
73
Bogdan, M0OOV
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It seems that JP105 is a nice place to sold a socket and pin holder and get in the dev-board the GND and +9V points. There are soldering places both on the mainboard and on the dev-board for JP105.
There remains to find a way to sold a pin holder and socket near the DC input I will use to connect tha wall charger for the batteries.
73 - Pierre - FK8IH
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Stan,
Thanks for your comment.
Looking at the rev3 Assembly Manual and Schematics it seems that I can send the +9V and Gnd from the 12-24 to 9V converter to JP101 on the mainboard. In which case I can glue with araldite the DC socket upside down and use it to plug in the charging DC current from the wall charger and solder to its two lugs now visible on its top the two wires from the LiFePO4 batteries. This would make a very easy modification to the QMX+ however I have one question: the schematics show JP101 as a 8 pins socket (pin 3 V_IN and pin 2 GND) and the assembly manual shows this JP101 as a 4 holes only footprints! I don't know what are the GND and V_IN holes on the mainboard footprints! Obviously I would use sockets and pinholders for these connections in order to keep the dev-board removable.
About the amp-speaker, I think the easiest way is to plug a 3.5 wire amp-speaker with inside batteries.
All in all there would be no visible modification to the QMX+ and make it an easy to transport outside xcvr with an EFHW antenna or my PAC&é vertical antenna.
Any comment about JP101 or any other suitable points where to connect the GND and +9V from the converter to the mainboard will be appreciated.
73 - Pierre - FK8IH
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Re: Observing CW sidebands?
Bogdan,
?
You might try checking CLK2 direct from the Si5351 for spurs, noise could be getting injected by
the final modulator, the TX_BIAS supply, or just some unrelated parallel trace somewhere.
?
Or it could be in the Si5351.
As Hans suggests, some low level spurs there would not be surprising.
?
The 100hz sidebands on the FT-991A sound suspiciously like power supply hum.
Perhaps a bit of noise from a full wave rectifier operating on 50Hz mains is getting into?
the power supply to the final, effectively modulating it.
?
As has been said this is an intellectual exercise, those sidebands are of such?
a low level that they really don't have any practical effect.
?
Jerry, KE7ER
?
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Re: Observing CW sidebands?
Hello Bogdan
I think there are several possibilities. Some kind of measurement artifact is one. Who knows. But on QMX, CW is transmitted as a single carrier. It isn't produced by modulating a sidetone to RF. The sidetone is produced separately purely for operator convenience, it has no involvement at all in the RF production. I think the main two possibilities if the spurs are really there, would be: - supply noise of some kind. Try a different power supply and see if the spurs are still present. Maybe they are. There could be a possibility of supply noise inside the QMX too, leaking into the PA supply. These spurs you noticed are very low level. So it isn't valid to say oh there's a choke here, an inductor over there, or a capacitor or few here. Capacitors and chokes don't delete?anything absolutely, they just attenuate it to a certain degree.?
- Some kind of spur inherent in the RF synthesis process in the '5351 Synth chip. If that was the case I think it would alter markedly depending on the operating frequency. So moving the operating frequency say, a few kHz, would move the spur. And it would not be in the same place on different bands. These signatures could be used to confirm or reject this possibility.?
Thank you all, I'm happy to hear that there is a general acceptance that they can exist and it's not only a misunderstanding on my part. What could be the reason though? And why such a large difference? i.e. at 1.5 kHz on QMX and +/-100 Hz on the Yaesu. Is there any audio modulation of some sort?
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@Evan I was under the impression that your points about the IF, sampling and downconveting only apply to RX not to TX. I did notice those spurs on the Icom as well, you are right, and I added a footnote comment on the chart. However, I believe I did not see the spurs on the Icom at all at a frequency span of 300 Hz which is a more zoomed in view.
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@Chris I can check if I see these spurs when transmitting via the terminal diagnostic mode and come back with an update tomorrow.
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QMX CW keyer & message memory glitch.
I have a pre-built QMX low band that I received a couple months ago. I made a few contacts from my home QTH before taking it out to do a POTA activation. Every worked perfect at home and the memory message also worked as designed.
When I was in the field, the first few contacts went well. Then in the middle of a contact my keyer (VK3IL pressure paddle), just quit working. Thinking it was the paddle, I unplugged it and plugged in my SP4 paddle and it would not work either.
Next I powered cycled the QMX and tried the keyer again and it was working.
After the power cycle, I tried using my memory message and it would loop the message nonstop until I intervened. I powered off the QMX, disconnected/ reconnected the battery, and powered the QMX back on. The memory message continued to loop nonstop. At
this point I was done trying to troubleshoot it in the field and just put it away and used my FT-891 to finish the activation.
Has anyone had a similar experience?
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QMX CW keyer & message memory glitch
I have a pre-built QMX low band that I received a couple months ago. I made a few contacts from my home QTH before taking it out to do a POTA activation. Every worked perfect at home and the memory message also worked as designed.
?
When I was in the field, the first few contacts went well. Then in the middle of a contact my keyer (VK3IL pressure paddle), just quit working. Thinking it was the paddle, I unplugged it and plugged in my SP4 paddle and it would not work either. Next I powered cycled the QMX and tried the keyer again and it was working.
After the power cycle, I tried using my memory message and it would loop the message nonstop until I intervened. I powered off the QMX, disconnected/ reconnected the battery, and powered the QMX back on. The memory message continued to loop nonstop. At this point I was done trying to troubleshoot it in the field and just put it away and used my FT-891 to finish the activation.
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Has anyone had a similar experience?
?
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Jerry, my LiFePo4 cells have already a battery management system. About the voltage, I guess I will power the QMX+ with 9V since the 4xLiFePo4 give between 14.2V fully charged and 12V discharged, 9V would be nice. Thanks for the idea to find the connections inside the box and attache the cells to the enclosure.
73 - Pierre - FK8IH
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Pierre, as you probably know, you probably want to include a battery
management system?to balance cells and avoid over-discharging or over-charging.
LiFePO4 is not as forgiving of overcharging as some chemistries.
This means can't overcharge some cells in a string of four to restore balance
while the remaining cells not yet fully charged catch up.
Do a web search for "4S LiFePO4 BMS".
?
Alternately, you could pop the four individual cells out of the battery pack
and put them into a commercial battery charger.
?
Jerry, KE7ER
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Pierre - FK8IH
Bob Peterson