Re: QMX/QMX+ internal Transmit Voltage measurement question
I do all of my software development either on Linux or MacOS and usually both at the same time. Years ago, Apple eliminated gcc and g++ from their tool chain and switched to clang. Clang is available on all *nix platforms but I¡¯m not sure if it¡¯s compatible with cross-compiling to STM binaries. The nicest thing about clang is its more human-readable warnings and errors. I don¡¯t know if it offers profiling though and can¡¯t state anything about its execution efficiency w.r.t. gcc/g++. Still, since clang is Apple¡¯s default compiler, I decided to use it under Linux as well to keep my make files consistent across both platforms.
I also use valgrind on Linux to check for memory leaks. Hans, you¡¯ve said you don¡¯t use dynamic memory allocation so that¡¯s not an issue. Of course, you still need to worry about stack overflow.
Floating point division is a CPU hog, considerably more than floating point multiplication. It¡¯s a necessary evil for statistics calculations such as averages, variance, and standard deviation. Like Hans, I¡¯ll take every opportunity to avoid division and implement it as multiplication if possible.
One nice feature in FPGA development is the ability to trade off DSP block utilization for execution speed. I can add more DSP blocks for faster execution time or allow slower execution speed to save DSP blocks.?
It can be tricky determining the best course of action in CPU environments where you don¡¯t have control over the hardware. But it certainly inspires innovation and deep learning of what works and what doesn¡¯t.
Tony AC9QY On Wed, Apr 16, 2025 at 6:52?AM Chris, G5CTH via <chris.rowland= [email protected]> wrote:
I'm not in the least surprised that SSB maxed out the processor.? Corollary of Parkinson's law maybe.? Processing requirements expand to match what is available.
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Do you use fixed point arithmetic?? This uses integer arithmetic but choosing a position for the binary point.? And choosing the values and ranges to make divisions in particular binary.? For example in this example if the factor was 6.4 instead of 5.7 the conversion in decivolts would be a 6 bit shift.?? It would take some careful resistor selection but with 1% resistors something could be done.
This is of course overkill for this measurement, which isn't done often, but the inner loops of the SSB code might benefit from using fixed point, and maybe even hand optimising for the really critical parts.? I've done that, using a profiler, or even setting and clearing an output pin and using a scope to see where most of the activity was, then had optimising.? Things such as avoiding register shifts and storage of temporary variables could save 20 to 30%.
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All really difficult but a lot of fun.
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Re: QCX Mini Displaying //???/??/
Hi Matt. The issue still really sounds like a loose connection somewhere. Maybe since you are sure your soldering is OK you could try giving a gentle twist to the tabs on the back side of the LCD module to tighten them up. The one that you had to bend per the instructions may need a tightening twist to it as well. Connections inside between the LCD unit and the backplane circuit are just contacts that need to stay reasonably tight. In the unlikely event that it's something glitching in the firmware, then a factory reset might fix it. If you don't have meaningful intelligence on the screen long enough to get through that process you could always do it by counting button pushes and rotary encoder clicks. I actually wrote down the "blind" procedure to do a reset. If you need that, let me know. Good luck ..73 ... Ron
New QCX Mini (20m) build and everything seems to be working except for the screen will go blank and/or display a mix of /'s and ?'s after the initial boot screen. Boot screen always displays both lines of text and then roughly half the time I get the random mix of ?//? on just the top line or a single black character on the top right. The other half of the time the screen displays the frequency on the top line and I'll get a few button presses before it again falls back to the ?/???? junk. Pushing any of the buttons updates the line but never goes back to anything other than a single black box or the junk characters.
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I've inspected the board pretty closely, re soldered pretty much everything on the board at this point, and checked continuity between the screen and IC2 pins which all seems to check out. I've also checked the voltage on all the screen pins with a multimeter and while they aren't exactly what is in the build guide they seem to be within the expected operating range. That about hits the limit of what I know to do for troubleshooting, any advice would be more than welcome.
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This is curious behavior - I believe there must be something defective in your QMX+.?
The memories in mine function perfectly, sending exactly what is in the memory every time.
With one exception: there is a firmware issue that can leave 'unseen' characters in the memory that get sent (I documented this in a separate thread) - but even in that case, it sends the exact same thing every time.
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Does yours always send correctly with an external key? (I'm wondering if this is a flaky TX issue rather than a flaky memory issue).
And it also is flaky with your logging program via CAT?
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If it is just flaky sending from the keyer memory, I would think maybe your processor/eeprom interface has a problem.
But CAT I think is purely in the processor, if your logger is using the KY commands to send - so it would be something different.
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Good luck - Stan KC7XE
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Re: QMX/QMX+ internal Transmit Voltage measurement question
Do you use fixed point arithmetic??
The QMX SDR is coded on both receive and transmit using floating point. A big advantage is that you know you've got 24 bits of precision in 32-bit floating point IEEE-754 format. With fixed point (or equivalently integer) you need to constantly worry about scaling your numbers so that the dynamic range window fits the numeric capacity. 24 bits of precision equates to 144 dB dynamic range and is of course way more than the radio hardware itself is capable of. So it's one less thing to worry about. The STM32F4-series have floating point and DSP hardware so it's handled very efficiently (if not infinitely so).?
73 Hans G0UPL
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Re: QMX+ with WA3TFS amplifier
On Wed, Apr 16, 2025 at 07:57 AM, AE5JE - Jim wrote:
plan is to use the QMX +5V PTT signal.? Inputting +5V to the base of the amplifier's T1
Jim, the QMX ptt signal will only source a few mA, so it may not work directly.? It is better to use it to drive the gate of a FET switch.
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Re: QMX+ with WA3TFS amplifier
Jamie, do you have C16 installed in the WA3TFS amplifier?? I plan to build my amplifier without C16 and test with the QMX.? Depending on those results, my backup plan is to use the QMX +5V PTT signal.? Inputting +5V to the base of the amplifier's T1 via the voltage divider.? That should turn T1 on and switch the relay.? This would replace using the rectified RF input to switch the relay and should make the PTT to TX delay effective.? Not an electronics expert, so we'll see if this works.? :-)
--
73,
Jim - AE5JE
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I wasn't able to find a suitable BPF combination that worked well for my QDX on 40-15m, and I've instead bypassed it for now with a 1200pf capacitor. This way, the LPF selected is always in line on receive, and I have tried running an external HPF (K9DP BCI filter) that cuts off everything below 3.5 mhz; creating a kind of wideband BPF.? I've played with values in Elsie to make a HPF on the same K9DP board with a 7mhz cutoff, but haven't implemented that yet. That's worked well enough in my US operating. (I know EU areas can have stronger SW BC signals near ham bands)?
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-Nate
N8BTR
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Ron... Tnx for the Heads up! You are correct. I'm scheduled for surgery this afternoon so I will be out of my shack for a while. I did re-check the IC's again and a couple ?are still questuinable. Thanks for your help... Ron ?
On Apr 16 2025, at 8:00 AM, Ronald Taylor via groups.io <wa7gil@...> wrote: Ron, it looks like you might be counting the IC pins wrong. You show about 12 v on pin 5 and about 2.5v on pin 8. It should be the opposite. Looking down on the top of the IC with the notch or dot at the top, the top left pin is 1 and it counts counter clockwise around from there with pin 5 at the bottom right and pin 8 at the top right. Hope that makes sense.?
Ron The QCX was returned to me as "Not Working." I set it up on a 12vDC battery and dummy load. Then used a signal generator and found that the QCX was receiving a signal. Also, using another radio (FT-891) I transmitted and the 891 received the QCX signal. Next I put in on the osciliscope and found that the output was 1V peak to peak. At this point I checked Q1, Q2 and Q3. All were functioning properly. Here I began checking the IC's. The pins I did not list here are within specs. The ones listed were not. IC5 pin 5 (2.28 is actually showing 12v IC5 pin 8 11.67) is 2.55 IC6 pin 3 (1.63) is 2.66 IC6 pin 5 (1.55) is 11.67 IC6 pin 8 (11.67) is 2.66 IC7 pin 3 1.99) is 2.60 IC7 pin 5 (1.89) is 11.67 IC7 pin 8 (11.67) is 2.66 IC8 pin 3 (0.65) is 2.57 IC8 pin 5 (0.65) is 2.57 IC8 pin 8 (11.67) is 2.60 IC9 pin 3 (0.65) is 4.49 IC9 pin 5 (0.67) is 11.67 IC9 pin 8 (11.67) is 2.56 IC10 pin 5 (4.21) is 11.67 IC10 pin 6 (3.94) is 5.94 IC10 pin 8 (11.67) is 5.90 This is as far as I got. Sorry for the 1st email, Hans. I have torn the bicep in my left arm and probably took too many pain killer before I emailed.. Hi Hi Any help will be most appreciated... Thank You Ron Pearson KA5HZV
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Re: Here's hoping for QMX+ v2
On Wed, Apr 16, 2025 at 09:28 AM, RS wrote:
Best of all, the QSX file could finally be closed once and? for all...
That file is already closed: /g/QRPLabs/message/140815This is a fun thread. Though amusing to note that many of the wishlist objects are already available: they just bear other names and other price-points. It is striking to note how "waterfall" was super-high-end a generation ago. And now it's being suggested (and possible!) for low-power portable devices. I read with great interest the review of the zbitx on QRPer this morning: The price is right for a cheapskate like me. But the conclusions that stuck out to me were the clunky UI and the significant battery drain. I'm frequently frustrated by touch screens: I appreciate the hardware buttons on QRP-Labs equipment. Especially in the field. The Penntek TR-45 wasn't selling the latest tech: its selling point was "There is a knob or switch for every function" (and the retro hardware S-meter is a cool touch). I have never had to worry about battery capacity with my QMX. Even when activating seven different parks in a day, or sitting and smelling the roses for a few hours in a single park, my battery slowly fades from 12v to 10v and the QSO's keep rolling in. What I *do* like from the zbitx is the clever external battery holder. I'm super pleased with my QMX purchases (one not yet built). In part because future firmware updates promise my radios are only getting better and more capable with age! It's like getting a new rig every six months: one I already know how to operate. And, having complete control of the rig brought out through the USB port means everyone who's really interested can go crazy designing their ideal UI for the QMX[+], waterfall and all! 73 de Todd W2TEF
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Re: QMX+ goes into safe mode with antenna tuned to 1.5 SWR
I agree with the other two answers. Pay close attention to the X502 antenna connection area. The jumper is critical of course. And more than one QMX+ has has a solder splash on the SMA connector pads ( under the BNC ) where no component is actually soldered so it does not get the scrutiny that most connections get. A center pin to ground is easy to occur here.?
73
Dick
W4PID
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Re: Here's hoping for QMX+ v2
The ideal product to me would look similar to the FX-4CR from the outside and contain a "rearranged" QMX+ inside. For this, the circuit would have to be redistributed on two QMX size PCBs, plus a display board with the colour LCD, and a speaker amp IC somewhere. The case (about twice as high as a QMX classic) would have sufficient space for two 4mm thin 2.8Ah Lipo cells ( why not a removable GK40) fitted inside. The front panel LCD would be similar to the 4CR, i.e. with frequency, spectrum, waterfall display and status information. The front panel would also have 6 or 8 push-buttons for what we need most, i.e. band up/down, filter narrow/wide, mode, tune, etc, with a couple of them user defined. All this would substantially improve the handling and user experience of these fine little rigs. The two original QMX push-buttons would of course remain so that the FW can be reused 1:1.?
With a target price say of $200 for the kit or $300 for the ?factory assembled and tested unit I'd certainly pre-order one at once.?
Adding a robust 10W MOSFET PA would be welcomed by many, but of course this is a major design change with a heap of consequences? e.g. cooling, larger toroids, higher cost, etc. etc. and we would be leaving the pure QRP segment.
Best of all, the QSX file could finally be closed once and? for all...
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Re: QMX CW issue, omits dits
Thanks a lot for your ideas, thanks Hans for your explanaition.
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Sometimes the easiest solution is the most likely. After some further experimenting I found that in fact it was a contact problem at the paddle jack. After fixing this, the keying now works as it should.
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Problem solved :-)
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73 de Michael DF9TZ
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Ron, it looks like you might be counting the IC pins wrong. You show about 12 v on pin 5 and about 2.5v on pin 8. It should be the opposite. Looking down on the top of the IC with the notch or dot at the top, the top left pin is 1 and it counts counter clockwise around from there with pin 5 at the bottom right and pin 8 at the top right. Hope that makes sense.?
Ron
The QCX was returned to me as "Not Working."
I set it up on a 12vDC battery and dummy load. Then used a signal generator and found that the QCX was receiving a signal. Also, using another radio (FT-891) I transmitted and the 891 received the QCX signal. Next I put in on the osciliscope and found that the output was 1V peak to peak.
At this point I checked Q1, Q2 and Q3. All were functioning properly.
Here I began checking the IC's. The pins I did not list here are within specs. The ones listed were not.
IC5 pin 5 (2.28 is actually showing 12v
IC5 pin 8 11.67) is 2.55
IC6 pin 3 (1.63) is 2.66
IC6 pin 5 (1.55) is 11.67
IC6 pin 8 (11.67) is 2.66
IC7 pin 3 1.99) is 2.60
IC7 pin 5 (1.89) is 11.67
IC7 pin 8 (11.67) is 2.66
IC8 pin 3 (0.65) is 2.57
IC8 pin 5 (0.65) is 2.57
IC8 pin 8 (11.67) is 2.60
IC9 pin 3 (0.65) is 4.49
IC9 pin 5 (0.67) is 11.67
IC9 pin 8 (11.67) is 2.56
IC10 pin 5 (4.21) is 11.67
IC10 pin 6 (3.94) is 5.94
IC10 pin 8 (11.67) is 5.90
This is as far as I got. Sorry for the 1st email, Hans. I have torn the bicep in my left arm and probably took too many pain killer before I emailed.. Hi Hi
Any help will be most appreciated...
Thank You
Ron Pearson KA5HZV
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Re: QMX/QMX+ internal Transmit Voltage measurement question
I'm not in the least surprised that SSB maxed out the processor.? Corollary of Parkinson's law maybe.? Processing requirements expand to match what is available.
?
Do you use fixed point arithmetic?? This uses integer arithmetic but choosing a position for the binary point.? And choosing the values and ranges to make divisions in particular binary.? For example in this example if the factor was 6.4 instead of 5.7 the conversion in decivolts would be a 6 bit shift.?? It would take some careful resistor selection but with 1% resistors something could be done.
This is of course overkill for this measurement, which isn't done often, but the inner loops of the SSB code might benefit from using fixed point, and maybe even hand optimising for the really critical parts.? I've done that, using a profiler, or even setting and clearing an output pin and using a scope to see where most of the activity was, then had optimising.? Things such as avoiding register shifts and storage of temporary variables could save 20 to 30%.
?
All really difficult but a lot of fun.
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Re: QMX and power bank PD
Thanks all. Looking forward to getting out there and giving it a go! I think I was just worried from all the stories of people damaging their QMX. I'm hoping the LEFS 8010 will be a good choice as I can hop across bands without a tuner - within the limits of the QMX I chose, I went for the middle one 60m to 15m. If I get good at CW TX/RX (and win the lottery) I might reward myself with a Begali one day!
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73
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and here is the one built by me with valuable assistance for trouble shooting. It is less noisy. but the tones are there !
--
Martin
DK3UW
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On Wed, Apr 16, 2025 at 01:19 AM, WB9YXA wrote:
As it stands right now, the SWR jumps around erratically, but the BIAS SMPS now looks 'normal'? 30.5 mA and 4% Duty cycle.
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The SWR will jump around erratically if there's no output power because the SWR calculation will be dividing two small numbers.
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4% duty on the bias SMPS seems small.? I'm seeing 15% with a 12V supply. ? AIUI the bias current is determined by measuring the ADC _BIAS voltage.? I don't recall hearing how this is converted to a current but it probably assumes that the circuit around the bias generation is correct.
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One thing to check is the output power independently of the QMX, measuring the peak voltage on your dummy load for example.? If you are seeing power then there could be a problem with T507 because this is what measures the power in the QMX.
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And I suggest that you do your tests at a lower voltage, 7V and 500mA max for example.? This will help your QMX to survive while you sort out what the problem is.
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Re: Trying to capture 2x16 LCD signal...
Hi Mike?
I'm not sure I know the answer to your question from memory but the HD44780 datasheet will tell you all you need to know, these things are 40+ years old now and remain the same.?
But my question is why why why! Aren't you making life very hard for yourself... I will soon add CAT commands to return the LCD contents, if you are trying to replicate the display elsewhere this could be a lot easier way to do it, than trying to reverse engineer the HD44780 and create a virtual shadow HD44780...
73 Hans G0UPL
I have been trying to capture the digital signals driving the 2x16 LCD on my fully functional QMX transceiver. ?
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I am using an application called Scopy and the ADALM2000 learning module hardware from Analog Devices.? I don't understand the captured data.? I am hoping someone on this forum is familiar with this protocol and can provide some insight.
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My two main questions I have are:
1) Should the Enable line go high when the microprocessor of the radio is writing to the screen?? From what I have captured so far these does not seem to be the case.? However the reference material I read on line about typical 2x16 LCD screens indicates the Enable signal means write to the screen.
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2) Should the Register Select (RS) line go high when the microprocessor is writing an ASCII character and low when it is writing a screen command?? My data collection shows that there seems to be far more RS pulses than Enable pulses, which I don't understand.
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Am am attaching a screen shot of the data collected when I power up the QMX receiver with the factory reset splash screen.? I have the Enable pin tied to input bit 0, the RS pin tied to input bit 1 and LCD data bit 0 through 7 tied to input pins 2-9 respectively.
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Any info on this would be greatly appreciated.
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Thanks in advance
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Mike (KC2EHR)
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I just went into Putty diagnostics and? discovered? something interesting. the tone is always there but on the lower bands it is deeper getting higher for each band and stay at the same height from 12 m on.? Here is a file from Audacity.
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That is the QMX+ built by QRP Labs. Mine sounds different but has the same sceme.
--
Martin
DK3UW
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Re: QMX/QMX+ internal Transmit Voltage measurement question
Why not multiple the voltage by 5700 to get the value in millivolts?
That would work also. But it's not necessary, it isn't a problematic or time-sensitive part of the code at all.?
73 Hans G0UPL
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Ronald Taylor
AE5JE - Jim
Todd W2TEF
Richard Hattaway