Re: QMX/QMX+ internal Transmit Voltage measurement question
You have a point. I measured as I said with key down. But , separately, looked at the TX voltage in the diagnostic screen while holding the T key. I assumed that the two were equivalent TX conditions since both seem to produce full power out. If this is not
the case, that both produce full power, then that would be interesting to know since many of us measure power out using the diagnostic screen.
Tony
AD0VC
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Hi Tony
How could you measure in TX Key down with speed zero, if you were in the Diagnostics screen viewing the voltage??
73 Hans G0UPL
I measured during TX, key down with speed set to zero.
Tony
I measured the TX voltage at the drain of the modulator with my DVM during transmit and I get a value within a few tenths of supply. This is in CW mode. But the diagnostic display still says TX voltage is 1.5 volts lower than supply.
Tony
AD0VC
Hi all
The ADC measurement voltage is multiplied in the code by 5.7 (due to the 10 / 47 potential?divider).?
It IS expected that the TX voltage is less than the supply voltage because the code is written this way. The gain of the PA modulator amplifier (Q512, Q513, Q514, Q515, Q507) is expected to be 6.24. When the system measures the supply voltage, it can therefore
calculate what it expects the maximum available PA modulator voltage to be. Or in other words, what DAC value to use for the desired maximum PA voltage. It needs to know?this to get the top of the Blackmann-Harris CW envelope shaping correct, and for the ALC
or CESSB in SSB generation. However there are component tolerances, and the supply voltage?is likely to drop a little further under high load, and for this reason a safety margin is built in, and this is why the TX voltage is less than the supply voltage.?
During Receive, the PA voltage is just set to the maximum DAC value, this means the PA voltage will be as close as it can get to the supply voltage. This is because we don't need to use that voltage for anything other than to minimize BS170 vDS capacitance
and therefore as far as possible, remove the PA from view during Reception.?
None of this is involved in the calibration or any issues with calibration.
Thanks Ludwig, I must have skipped a step in the math...
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Re: QMX/QMX+ internal Transmit Voltage measurement question
Hi Tony
How could you measure in TX Key down with speed zero, if you were in the Diagnostics screen viewing the voltage??
73 Hans G0UPL
I measured during TX, key down with speed set to zero.
Tony
I measured the TX voltage at the drain of the modulator with my DVM during transmit and I get a value within a few tenths of supply. This is in CW mode. But the diagnostic display still says TX voltage is 1.5 volts lower than supply.
Tony
AD0VC
Hi all
The ADC measurement voltage is multiplied in the code by 5.7 (due to the 10 / 47 potential?divider).?
It IS expected that the TX voltage is less than the supply voltage because the code is written this way. The gain of the PA modulator amplifier (Q512, Q513, Q514, Q515, Q507) is expected to be 6.24. When the system measures the supply voltage, it can therefore
calculate what it expects the maximum available PA modulator voltage to be. Or in other words, what DAC value to use for the desired maximum PA voltage. It needs to know?this to get the top of the Blackmann-Harris CW envelope shaping correct, and for the ALC
or CESSB in SSB generation. However there are component tolerances, and the supply voltage?is likely to drop a little further under high load, and for this reason a safety margin is built in, and this is why the TX voltage is less than the supply voltage.?
During Receive, the PA voltage is just set to the maximum DAC value, this means the PA voltage will be as close as it can get to the supply voltage. This is because we don't need to use that voltage for anything other than to minimize BS170 vDS capacitance
and therefore as far as possible, remove the PA from view during Reception.?
None of this is involved in the calibration or any issues with calibration.
Thanks Ludwig, I must have skipped a step in the math...
|
Re: QMX/QMX+ internal Transmit Voltage measurement question
I measured during TX, key down with speed set to zero.
Tony
toggle quoted message
Show quoted text
I measured the TX voltage at the drain of the modulator with my DVM during transmit and I get a value within a few tenths of supply. This is in CW mode. But the diagnostic display still says TX voltage is 1.5 volts lower than supply.
Tony
AD0VC
Hi all
The ADC measurement voltage is multiplied in the code by 5.7 (due to the 10 / 47 potential?divider).?
It IS expected that the TX voltage is less than the supply voltage because the code is written this way. The gain of the PA modulator amplifier (Q512, Q513, Q514, Q515, Q507) is expected to be 6.24. When the system measures the supply voltage, it can therefore
calculate what it expects the maximum available PA modulator voltage to be. Or in other words, what DAC value to use for the desired maximum PA voltage. It needs to know?this to get the top of the Blackmann-Harris CW envelope shaping correct, and for the ALC
or CESSB in SSB generation. However there are component tolerances, and the supply voltage?is likely to drop a little further under high load, and for this reason a safety margin is built in, and this is why the TX voltage is less than the supply voltage.?
During Receive, the PA voltage is just set to the maximum DAC value, this means the PA voltage will be as close as it can get to the supply voltage. This is because we don't need to use that voltage for anything other than to minimize BS170 vDS capacitance
and therefore as far as possible, remove the PA from view during Reception.?
None of this is involved in the calibration or any issues with calibration.
Thanks Ludwig, I must have skipped a step in the math...
|
Re: QMX/QMX+ internal Transmit Voltage measurement question
I measured the TX voltage at the drain of the modulator with my DVM during transmit and I get a value within a few tenths of supply. This is in CW mode. But the diagnostic display still says TX voltage is 1.5 volts lower than supply.
Tony
AD0VC
toggle quoted message
Show quoted text
Hi all
The ADC measurement voltage is multiplied in the code by 5.7 (due to the 10 / 47 potential?divider).?
It IS expected that the TX voltage is less than the supply voltage because the code is written this way. The gain of the PA modulator amplifier (Q512, Q513, Q514, Q515, Q507) is expected to be 6.24. When the system measures the supply voltage, it can therefore
calculate what it expects the maximum available PA modulator voltage to be. Or in other words, what DAC value to use for the desired maximum PA voltage. It needs to know?this to get the top of the Blackmann-Harris CW envelope shaping correct, and for the ALC
or CESSB in SSB generation. However there are component tolerances, and the supply voltage?is likely to drop a little further under high load, and for this reason a safety margin is built in, and this is why the TX voltage is less than the supply voltage.?
During Receive, the PA voltage is just set to the maximum DAC value, this means the PA voltage will be as close as it can get to the supply voltage. This is because we don't need to use that voltage for anything other than to minimize BS170 vDS capacitance
and therefore as far as possible, remove the PA from view during Reception.?
None of this is involved in the calibration or any issues with calibration.
Thanks Ludwig, I must have skipped a step in the math...
|
?
I am surprised you can't hear the 1000 Hz tone when you are in CW mode with the bandpass set to 300 Hz or wider.??
Do you also see the tones on 12M and maybe 10M ?? Other bands as well, but at much reduced levels??
?
I believe the tones are created within the QMX+ as I never have my computer connected normally.? ?I use the QMX+ for CW only at present, and the tones are always there on 6 and 12 M at a level that makes the radio non functional on those bands, and are present at lower amplitudes on 10M . .? I did load WSJT on my little Raspberry Pi and was able to 'see' the tones just as you have pictured above.? I don't believe the interference is being introduced on the USB cable.? ?This has been the experience of others as well.
?
I also have both LB and HB QMX radios ( no + ) and the tone does not exist on those radios at all.??
?
My efforts and the efforts of others are well documented in 110457498.? I will continue to try to solve the issue, but life keeps getting in the way of adventure HIHI
?
73
Dick
W4PID
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Re: QMX/QMX+ internal Transmit Voltage measurement question
Hi all
The ADC measurement voltage is multiplied in the code by 5.7 (due to the 10 / 47 potential?divider).?
It IS expected that the TX voltage is less than the supply voltage because the code is written this way. The gain of the PA modulator amplifier (Q512, Q513, Q514, Q515, Q507) is expected to be 6.24. When the system measures the supply voltage, it can therefore calculate what it expects the maximum available PA modulator voltage to be. Or in other words, what DAC value to use for the desired maximum PA voltage. It needs to know?this to get the top of the Blackmann-Harris CW envelope shaping correct, and for the ALC or CESSB in SSB generation. However there are component tolerances, and the supply voltage?is likely to drop a little further under high load, and for this reason a safety margin is built in, and this is why the TX voltage is less than the supply voltage.?
During Receive, the PA voltage is just set to the maximum DAC value, this means the PA voltage will be as close as it can get to the supply voltage. This is because we don't need to use that voltage for anything other than to minimize BS170 vDS capacitance and therefore as far as possible, remove the PA from view during Reception.?
None of this is involved in the calibration or any issues with calibration.
Thanks Ludwig, I must have skipped a step in the math...
|
Re: Available Hand Mics for QMX SSB ?
Jason I am interested in a printed version, but can't find your DM info.
Thanks,
Bill? W3WJ
?
?
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I was experiencing many of the same problems discussed in this thread, so I've been following the advice that's been given.? ?My QMX+ and WSJT-x are now on good speaking terms!? CAT control (including "PTT") are working fine, and I'm using the QMX radio setting.
?
I'd been running an old version of WSJT-x (v2.6.1) with my DigiRig interface and FT-817.? I created a WSJT-x configuration for the QMX+, using the TS480 radio setting.? It would change bands ok, but every time I changed bands on WSJT-x it would report an error and ask me to reconfigure.? I'd click "yes", then cancel out of the settings, and it would be ok.? It would never transmit though.? WSJT-x would crash as soon as I clicked the "Tune" button.
?
Anyway, here's what worked for me (thanks Muhsin):
1- Install the latest version of WSJT-x (v2.7.0).? I did this by downloading the installation file and having it install in a different folder from my old version.? I then created new shortcuts to run the new version.? Somehow during the process it was smart enough to copy over my existing configuration files.? When I opened the new version all of my setups were there.??
?
2- Switched to my QMX+ configuration and tried changing bands and transmitting.? It reported a CAT error every time and wanted me to check setup.? It didn't matter which Radio I was using (TS430, QDC or QMX).
?
2- I didn't do anything with WSJT-x's "Update HamLib" button.? ?Went to GitHub to download the Zip file for v 4.6.2 (Windows 8.1, 64 bit).? Unzipped the downloaded folder and found the LibHamLib-4.DLL file.??
?
3- Copied LibHamLib-4.DLL to the BIN folder of my WSJT-x installation.? But there was no change.? I later discovered that the BIN folder was read only and that the original file was still there.? After changing it to r/w, I copied the DLL file, and now it all works.
?
?
Anyway, as discussed in this thread, the LibHamLib.DLL that is bundled with the latest WSJT-x version is "broken".? Downloading the HamLib Zip file, extracting the LibHamLib-4.DLL, and then copying it into the WSJT-x BIN folder did the trick.
?
Thanks to all for your help; I never would have figured it out on my own.
?
Larry
?
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Re: QMX CW issue, omits dits
Thanks for the ideas so far.
?
As I am used to Iambic A I also choose this option on the QMX.
?
Incoming RF obviously is not the problem as this issue also occurs in practice mode. To be shure I tried a dummy and got the same result.
?
Could it be that the processor is not fast enough by handling the paddle input? I found that the QMX occasionally even does not send single dits as for an 'e' letter. In one case after sending some text with medium speed (20) the QMX hang by sending a continuous tone so I had to switch off power.
?
None of my QCX showed this behaviour at any time.
?
I am puzzled...
?
73 de Michael DF9TZ
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Really liking my QMX+ too. There are still a few things I don't know how to do yet, but overall it is just what I wanted for my bedside station that I use before going to sleep. Worked Slovenia from Ohio a couple days ago. Awesome.?
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Re: Help with partially fried QMX
Sorry for OT.
Hello Stan, thanks for your praise. But for me it's dangerous to believe in it. You only don't know when I was wrong :-).
73 Ludwig
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I’ve had my QCX+ up and running for a couple of weeks now at home, and have made many QRP qso’s on it and a OCFD. ?I find the hobby so rewarding using a new language I learned recently, and using a rig that I built! ?Thanks goes out to QRP Labs for great kits! ?Anyone can build these kits with patience and a hot iron…if I can, you can! ?Can’t wait to get outside here in Northern Minnesota with the QMX, Spring is just springing up here.?
Thanks Hans!?
72/73
--
Trevor (N0YMA)
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Re: First attempt at WSJT-X failed
Just a quick comment: If You use Icom ATU such as AH-4, the tuner has a buildt-in attenuator that attenuates the RF signal something like 15 dB while?tuning. Hence?showing approx 50 Ohm impedance even while tuning.? The tuner is specified to have a 5-15w input signal, but in my experience it works also from 2-3w.?
A simple interface for starting the tune process with Icom ATUs can be buildt like this:? 
This is likely due to your use of the antenna tuner while transmitting at full power.? When that ATU switches its relays to find a match, it presents momentary 'high SWR' to the QMX, causing it to go into SWR protect.? [Depending on your ATU, this may also happen even if it doesn't 'tune', when it switches to its tune memory settings for the current frequency.]
?
What I recommend doing is disabling the 'auto' on your ATU during normal operation, and when you change bands/frequencies and need to tune again, turn back on the 'auto', and use the QMX Hardware tests -> Tune SWR feature to give a reduced-power signal to activate the tuner auto-tune.? The SWR protect is automatically disabled in this mode, and the reduced power will remove risk of blowing your finals due to high SWR.? The default setting is 50% (voltage), 1/4 power.?? If this is too low for your tuner, turn it higher, maybe up to 75% (Protection menu -> Tune %).? This is how the QMX was designed to adjust tuning.
?
Some others don't like to do that, so they disable SWR protection, or set its threshold very high, so it won't trip when the ATU switches.? But do this at your own risk: it will likely work fine for a good while - but the momentary high SWR events may eventually wear down your finals and blow them.? There have been a few posts in this forum in the past about blown finals due to ATU switching.
?
Or just use an antenna that already has an SWR of about 1.7 or less - and don't use a tuner.? There is almost no functional difference in tuning an SWR of 1.7 down to 1.0 vs. not using a tuner.? The small loss in the tuner inductors is about the same penalty as a bit higher SWR.
?
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Re: QMX repair and diagnosis by W1NC
Yeah I made a few mistakes on mine. ?So thankful Jeff was able to bail me out.
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Re: Available Hand Mics for QMX SSB ?
Certainly!??
?
For anyone who wants to print their own:
?
?
If anyone wants a printed version with the threaded insert already in and the screw, DM me.? I have a few colors other than the one I used for the picture.
?
73
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Re: QMX pre-build 97775 has arrived
You're absolutely right Mark; Hans designed marvelous little transceivers. Mine are working great.
?
On a cautionary note, you might open the Operations Manual and fast scroll (hold PageDown button), stopping wherever you see RED text. Hans did a fine job of offering warnings in the manual.
Other parts of the manual I found most helpful were about the CW Filters and AGC.
?
--
72 de N4REE, Bob Easton - QRP CW forever
https://bob-easton.com/n4ree
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QMX - Constant 700Hz Tone on 40M, 17M, and 15M Bands
Hey everyone,
I recently bought a ready-assembled QMX after my DIY attempt didn’t quite work out (let’s call it a “successful failure” ?). Funny enough, I had no issues building the QMX+, QDX, or even the QCX Mini before.
With the assembled QMX, I’m getting a continuous tone every 700Hz on the 40M, 17M, and 15M bands. All the other bands are working fine.
Here’s what I’ve tried so far:
-
Factory reset
-
Upgraded to the latest beta firmware
-
Tested with different batteries and power supplies
-
Swapped USB cables
-
Connected to both a laptop and an iPad running iFTX
One key observation: these unwanted tones only appear when an antenna or dummy load is connected. Without any load, the issue disappears. That makes me lean toward a hardware issue—maybe something in the PA section or related to RF feedback.
I’m attaching some test results in case anyone spots something I may have missed. The timeslots on the JTDX without noise is when I disconnected the dummy load.
Any thoughts, suggestions, or similar experiences would be greatly appreciated!
Thanks in advance!
DL7EDU - LU5VQV
?
  
?
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Martin,
?
I've seen these on other bands as well and I'm fairly certain that this is an RF artifact that comes from the USB connection signaling.?
?
See if you can lower the amplitude of those spurs by adding a common mode choke to your USB cable. I haven't been able to eliminate them completely but I have been able to drop them to an acceptable amplitude.
?
Greg,
N1TR?
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Re: Available Hand Mics for QMX SSB ?
The printed case for the qrp guys microphone looks awesome! Are you considering sharing the design?
I too have an aversion to taking a beautiful circuit board and stuffing into a pvc tube!
?
73
Jim K8JK
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2 Audacity files how? 6 m sounds in Digi and CW
--
Martin
DK3UW
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Richard Hattaway
Braden Glett
UPNORTHOF48 :
Jason
N4REE - Bob
James Kvochick