|
QDX HB Build Notes
6
#qdx
#9v
#mods
Just wanted to share what I ended up doing for my latest QDX build. This is the first of 3 I intend eventually to operate remotely and probably into a Hardrock 50, so reliability is key. I'm loving the QDX only connecting to the computer with a single USB, no audio controls/cables, and directly operating in WJST-X. A few less things to go wrong, especially operating remote. Stats: Post Mar 2023 Rev 5 (T37-17 LPF Toroids) 9V w/ WTST. 1.10 FW installed. TN0110 finals instead of BS170, special heat sink added. 1N4148 Diode across L14 Alternative USB Port (per Jeff Moore's note.) I measured a few of my toroids with capacitors and NanoVNA. Was getting higher #s than spec'd, more than 20% higher. So ignored that initially, and built as manual suggested for the LPFs. After seeing lower output on 15 vs 17, and 10 vs 12, removed some turns. This pushed things in the right direction, and tells me maybe my measurements actually weren't far off. I could go farther, but I'm happy enough with the output to stop here, especially if I mostly will use this unit at 8V and feeding a Hardrock 50. Ended up with: LPFs Turns Suggested Turns Used L2 21 20 L6 21 21 L3 12 11 L8 12 12 L4 13 12 L10 14 13 Your results may vary, of course. Just my experience with this batch of toroids. Power stats on 9V: 168ma in receive. TX was 980 to 1100 ma, depending on band. Final power outputs, (lowest peak to peak value seen after 5+ seconds, into a QRP-Labs Dummy Load and a 200 mhz scope): 20M: 4.4w 17m: 4.6w 15m: 3.8w 12m: 4.0w 10m: 3.9w The heatsink: Wakefield LTN20069, $1.50 from Mouser. I drilled and tapped it for the 3mm screw a bit off center. It's 16mm square, and the original washer is 12mm. Needed to make sure it didn't hit the transformer. The TN0110s are reversed, so the flat part of the TO-92 case is against the heatsink. So went from 101 cubic mm of steel to over 1000 cubic mm of aluminum. It fits in the case with clearance. USB port; It does feel like a better fit than the supplied one, a bit more secure. This was another Mouser purchase for $1.20. Next up: Need to build a QRP-Guys SWR and Power meter kit, as well as their EFHW kit with tuner for 40-15m. Then I'll be trying to build a MidBand 40/30/20/15 QDX, and maybe 17M will work if I'm lucky. The Midband, if it works, will be my POTA/Travel rig that I'd use with EFHW. -Nate N8BTR
|
|
Original QCX Case
Hello Everyone, been a while. Moderator, If this is against the list rules please delete it. The other day I got a message requesting one of those cases I used to sell for the original QCX. Normally I just say that I don't make them anymore. But it got me to thinking, I have an 80 meter QCX kit sitting in a drawer and I'm going to need a case for it. So I told the gentleman that I would pull out the original files and print one for him. So it seems that I am back in the business of making that particular case. If you have one of the original kit radios maybe it is time to pull it out of the drawer and build it ;) Anyway here are links to the videos which I used to send anyone that asked about the case. I'm still using the original files. https://www.freeantennas.com/QCX/QCX-3_0.mp4 https://www.freeantennas.com/QCX/QCX-wiring.mp4 So that's my story and I'm sticking to it. w4mhz Mike
|
|
I'd like to know the firmware and hardware rev from anybody who has trouble with the QMX 3.3 and 5.0v power supplies. Mostly, I'd like to know how often these failures occur with the most recent firmware and hardware. If that gets noted here in the forum, the pressure increases to find a more robust solution. Symptoms might be a bad diode at D108 or D109, a fried processor, fails to work after jiggling the power connector, fails to work after accidentally shorting a power supply with a probe, fails to work after multiple short power button presses. As I previously reported, I have some linear regulators on a one inch square scrap of vector board that plugs into JP105, this seems to work well after some minor mods to the QMX. Specifically, need to lift the drain lead of Q106 and Q107 to disable the old SMPS's, need to add 200k in parallel with R112 and R113 so the firmware thinks it's seeing a bit more than 3.3v and 5v (it hangs if it sees a wee bit less) and short drain to source across Q111 so the 3.3v linear can drive ADC_3V3. I'd prefer that Hans change the firmware such that at power up it first checks if LIN_REG_EN is low, and if so skips all the SMPS start up and voltage checks. Then the only mod to the QMX would be to add a 10k resistor from LIN_REG_EN to ground. I don't encourage others to repeat my efforts at this time unless this is simply something you enjoy doing. Odds of blowing up your QMX are greater with my mods and hacks than they are with the old SMPS's. Success is not guaranteed. Reports of SMPS failures are no longer very frequent with Hans' latest firmware, especially given that there are thousands of QMX's in operation. As Hans has said, there are many different kinds of failures being reported in the forum. The majority are due to bad soldering, especially around attempts to burn the enamel off of the magnet wire. Fortunately, most failures are easy to repair. Unfortunately, an SMPS failure often blows the 100 pin STM32F446 processor. I feel that the primary issue with the old SMPS's is that the voltage gets checked by the processor only once every millisecond or so. That's fine if everything works as it normally does, but something unusual can upset things faster than the processor can react. For example, if the 5v rail is momentarily shorted to ground by a scope probe, the processor might increase current to maintain 5.0v but not react fast enough when the short goes away. Designing an SMPS from scratch (or in firmware) is a difficult exercise in control system theory. https://ludens.cl/Electron/loops/loops.html I just received my Kicad PCB fab for a one inch square board to replace my linear regulator vector board. This design has a couple SOT23-6 SMPS IC's. There's a huge number of different parts from different venders to choose from. Max current varies from 500ma to 2A. They operate at frequencies varying from 0.5 MHz to 2.2 Mhz. Cost can be as little at $0.10. Provision is made to allow the board to be fully shielded using cheap copper foil, held up by L shaped header pins. I am designing for the cheapest SMPS IC's which operate at an internally determined frequency, more expensive part (still under $1) can be driven by an external clock source such as a processor PWM pin to eliminate any birdies. The board can be separately built and fully checked out, including how it behaves with an intermittent or varying Vin, momentarily shorted outputs, momentary low current demand, and changes in temperature. It could be temporarily plugged into header pins at JP105 of the QMX, or permanently soldered in place to those header pins. If plugged in, I would recommend adding a soldered wire connection for ground, since if that flakes out momentarily it could be disastrous for the QMX. If it's successful, perhaps we of the forum can make it available as a kit. Or perhaps Hans would like to add it to his shop for purchase. Jerry, KE7ER I started this thread in response to this post /g/QRPLabs/message/139515 Re: QMX+ shutdown problem On Sat, Feb 22, 2025 at 04:10 AM, Kevin (KQ4DTX) wrote: Je
|
|
QMX+ SWR Sweeps FW bug report
2
I'm not sure if Hans reads every message so I am posting this with its own heading. I discovered that the SWR sweep test does not actually sweep if the rig is set to use VFO B. Other sweeps seem to work correctly with VFO B selected. Tony AD0VC
|
|
QMX+ All LPF Sweeps Are Bad
3
#lpf
#QMXplus
I have assembled and have working a QMX+, with one caveat; all of the LPF sweeps are bad. The audio filter sweeps, RF filter sweeps, image sweeps, and SWR sweeps look reasonable, although on a couple of bands the SWR sweeps aren't flat across the entire bandwidth swept, but were always good in the ham band frequencies. The I/Q sweeps all looked good except for 160 Meters where the phases were in sync for some reason. Not really a problem for me, I don't own that much wire. Here's the real problem. All of the LPF sweeps are bad. For example: 0 | * .* * * * .* * * . * * .* * * . * * * . | * * * .* * * * .* * * * * * * * .* * * * * * * *. | * * ** * .* * * * .* ** ** ** ** ** ** * * .* * * * ** * * * ** | ** ** ** **.* * * * ** ** ** ** ** ** ** ** * .* * ** ** ** * * * * * | ** ** ** **.** * ** ** ** ** ** ** ** ** ** ** **.* ** ** ** ** ** * ** * * | ** ** ** **.***|*** ** ** ** ** ** ** ** ** ** *** *** ** ** ** **** ** * * | ** ** ** *** **|** *** ** ** ** ** ** ** ** *** ** *** ** ** ** *** *** * * | ** ** *** ** **|** ** ** ** ** *** ** ** *** ** ** ** ** *** *** ** ** ** * | * *** *** ** **|** ** ** ** ** ** **.*** *** ** ** ** ** *** *** ** ** ** * | * * * * * **|** ** ** * * * * .* * * * ** ** ** * *. * * ** ** * | * * * * * *|* * *. * * * * .* * * * * * * * *. * * * * * | * * * * * |* * *. * * * * .* * * * * * * * *. * * * * * |* * * * * | * *. * * * * .* * * * . * * *. * * * * |* * * * . | *. * * * * .* * * * . * * *. * * * |* * * * . | *. * * * * .* * * . * * *. * * * |* * * * . | . * * * .* * * . * *. * * |* * * . | . * .* * . *. * |* * . | . . * . *. * |* . | . . . . . |* . | . . . . . -8 |* . | . . . . . ---------------------------------------------------------------------------- 6 9 12 15 18 21 0 |. *. * * . . . . . . |.* *. * * * . * * . * *. * *. * * * .* |.* * ** * * * . * * * .* * *. * * *. * * * * * .* |.* * * ** * * * . * * * .* * *. * * *. * * * * * * .* |** ** ** ** **** ** ** ** * * ** * *. * * *. * * * * * * **.* |** ** ** ** **** ** ** ** * * ** ** ** *.** ** ** ** * ** ** ** * ** **.* |** ** ** ***|*** ** ** ** **** ** ** ** *.** ** ** ** * ** ** ** * ** **.* |** ** ** ***|** *** ** ** **** ** ** *** *** ** ** **** ** ** **** ** **.** |* *** *** .*|** *** ** *** *** ** ** *** *** ** ** *** *** ** *** *** *** * |. *** *** .*|** ** *** *** ** *** *** ** ** *** *** ** *** ***.** *** *** * |. ** ** * .*| * *** *** ** ** **** ** ** *** *** ** ** ****.** *** *** ** |. * * * .*| * * ** * ** ** ** * * * ** ** * .* * * *.** ** * * * |. * * * .*| * * .* * ** *. * * * * * * * .* * * *. * * * * * |. * * * . | * * .* * *. * * * * * * * .* * * *. * * * * * |. * * * . | * * .* * *. * * * * * * . * * *. * * * * |. * * * . | * .* * *. * * . * * * . * * *. * * * |. * * * . | * .* * *. * * . * * * . * *. * * . |. * * . | * .* *. * * . * * * . * *. * . |. * . | * .* . * * . * * . * *. * . |. . | .* . * . * . * . * . -7 |. . | .* . . * . . * . ---------------------------------------------------------------------------- 16 24 32 40 48 56 64 72 All of the other bands exhibit a similar pattern. I tried looking for something common to all of the filters, but nothing I came up with made any sense given that the other sweeps were 'normal'. Since everything looked OK except for the LPF sweeps, I decided to perform a real-world test. I hooked it up to my EFHW at 20 feet and worked Oklahoma on 40 Meters FT8, so the transceiver is working. I don't have the necessary test equipment to check the spectral purity of the output signal so I'm hesitant to continue using it on the air until I resolve this problem. I tried searching for a solution both here and with Google and read a lot about fixing issues I don't have, but nothing that pointed me in the right direction. Thanks all for the great ideas I'm about to receive. Andy WB9YXA
|
|
All LPF Sweeps Are Bad
2
I have assembled and have working a QMX+, with one caveat; all of the LPF sweeps are bad. The audio filter sweeps, RF filter sweeps, image sweeps, and SWR sweeps look reasonable, although on a couple of bands the SWR sweeps aren't flat across the entire bandwidth swept, but were always good in the ham band frequencies. The I/Q sweeps all looked good except for 160 Meters where the phases were in sync for some reason. Not really a problem for me, I don't own that much wire. Here's the real problem. All of the LPF sweeps are bad. For example: 0 | * .* * * * .* * * . * * .* * * . * * * . | * * * .* * * * .* * * * * * * * .* * * * * * * *. | * * ** * .* * * * .* ** ** ** ** ** ** * * .* * * * ** * * * ** | ** ** ** **.* * * * ** ** ** ** ** ** ** ** * .* * ** ** ** * * * * * | ** ** ** **.** * ** ** ** ** ** ** ** ** ** ** **.* ** ** ** ** ** * ** * * | ** ** ** **.***|*** ** ** ** ** ** ** ** ** ** *** *** ** ** ** **** ** * * | ** ** ** *** **|** *** ** ** ** ** ** ** ** *** ** *** ** ** ** *** *** * * | ** ** *** ** **|** ** ** ** ** *** ** ** *** ** ** ** ** *** *** ** ** ** * | * *** *** ** **|** ** ** ** ** ** **.*** *** ** ** ** ** *** *** ** ** ** * | * * * * * **|** ** ** * * * * .* * * * ** ** ** * *. * * ** ** * | * * * * * *|* * *. * * * * .* * * * * * * * *. * * * * * | * * * * * |* * *. * * * * .* * * * * * * * *. * * * * * |* * * * * | * *. * * * * .* * * * . * * *. * * * * |* * * * . | *. * * * * .* * * * . * * *. * * * |* * * * . | *. * * * * .* * * . * * *. * * * |* * * * . | . * * * .* * * . * *. * * |* * * . | . * .* * . *. * |* * . | . . * . *. * |* . | . . . . . |* . | . . . . . -8 |* . | . . . . . ---------------------------------------------------------------------------- 6 9 12 15 18 21 0 |. *. * * . . . . . . |.* *. * * * . * * . * *. * *. * * * .* |.* * ** * * * . * * * .* * *. * * *. * * * * * .* |.* * * ** * * * . * * * .* * *. * * *. * * * * * * .* |** ** ** ** **** ** ** ** * * ** * *. * * *. * * * * * * **.* |** ** ** ** **** ** ** ** * * ** ** ** *.** ** ** ** * ** ** ** * ** **.* |** ** ** ***|*** ** ** ** **** ** ** ** *.** ** ** ** * ** ** ** * ** **.* |** ** ** ***|** *** ** ** **** ** ** *** *** ** ** **** ** ** **** ** **.** |* *** *** .*|** *** ** *** *** ** ** *** *** ** ** *** *** ** *** *** *** * |. *** *** .*|** ** *** *** ** *** *** ** ** *** *** ** *** ***.** *** *** * |. ** ** * .*| * *** *** ** ** **** ** ** *** *** ** ** ****.** *** *** ** |. * * * .*| * * ** * ** ** ** * * * ** ** * .* * * *.** ** * * * |. * * * .*| * * .* * ** *. * * * * * * * .* * * *. * * * * * |. * * * . | * * .* * *. * * * * * * * .* * * *. * * * * * |. * * * . | * * .* * *. * * * * * * . * * *. * * * * |. * * * . | * .* * *. * * . * * * . * * *. * * * |. * * * . | * .* * *. * * . * * * . * *. * * . |. * * . | * .* *. * * . * * * . * *. * . |. * . | * .* . * * . * * . * *. * . |. . | .* . * . * . * . * . -7 |. . | .* . . * . . * . ---------------------------------------------------------------------------- 16 24 32 40 48 56 64 72 All of the other bands exhibit a similar pattern. I tried looking for something common to all of the filters, but nothing I came up with made any sense given that the other sweeps were 'normal'. Since everything looked OK except for the LPF sweeps, I decided to perform a smoke test. I hooked it up to EFHW at 20 feet and worked Oklahoma on 40 Meters FT8, so the transceiver is working. I don't have the necessary test equipment to check the spectral purity of the output signal so I'm hesitant to continue using it on the air until I resolve this problem. I tried searching for a solution both here and with Google, read a lot about fixing issues I don't have but nothing that pointed me in the right direction. Thanks all for the great ideas I'm about to receive. Andy WB9YXA
|
|
QCX+ Menu 8.5 Ref frq
4
I would like to know if I can apply the following procedure to calibrate the Ref frq without GPS? Using a QCX+ 20M Band I would go to WWV 15MHz and read precisely the frequency for a zero beat. If I read 15.003.00 could I modify menu 8.5 to read 25.005.000 with the TCXO and have a more precise QCX+? 73 - Pierre - FK8IH
|
|
QMX+ shutdown problem
16
#qmx
#QMXplus
#shutdown
My newest QMX+ kit Rev 3 arrived and was assembled exactly one week after ordering! The diagnostics test page showed output power (0W) and SWR (random values). Everything else was OK. All sweep tests showed strange results. Yes, the dummy load was in place. So I decided to power off and check all solder joints again. The QMX was on the table without the enclosure and I did not get a good grip on it. As I pressed the Vol button for power-off the QMX moved on the table and the long button press was interrupted, giving *two* long presses like keying Morse M. The display flashed abnormally showing some text and dimmed. All happened so quickly that I did not see exactly what happened. No smoke, no hot components. Now I can not power-on as the radio does not react to any button press. Nothing happens. If jumpered for forced firmware update, no flash drive appears on the PC. This could be a firmware problem. Is it possible that the second long press of the Vol button started the power-on cycle while still powering off and writing data to the flash memory? Clearly, while performing power-off and saving data into the flash memory, the firmware should ignore the button press for power-on. -- 73 Matti OH6BEX
|
|
QMX won’t power up
10
Hello. I was using my QMX on 40m and 20m FT8 with a known good antenna and computer connection, successful QSOs, and no SWR lock outs or other signs of issue. The QMX screen went to all backlight with no LCD characters displayed for 1-2 sec and then went to a mix of full block LCD and some apparently random characters. Screen has no obvious physical damage. I was not transmitting at the time. I attempted basic battery / power troubleshooting to no avail. With a known good power source, it will not power on. Confirmed it is not limited to a screen issue, there is no RX as tested with audio output. What other troubleshooting is recommended? I’m ok with basic electrical repair, but don’t see myself doing and surface mount repairs. And I’m hoping there’s a possible test to rule out failed components and possibly an easy fix. I have explored the archives and didn’t see a similar problem noted. Thanks for any help.
|
|
Well, I bit the bullet and installed the 003 FW. Update of FW went all fine, no issue there. I wired up a electret mic I found in my junk box. Tested the mic on pc and sounded fine. I made an adapter using the electret mic and a foot switch for ptt. The Mic and ppt switch works. But... Testing SSB TX with QMX on dummy load and listening on my ICOM 7300, the audio is badly distorted before calibration and even worse post calibration. So much so that the speech is unintelligible. The audio sounds like the QMX is only picking up the peak signals from my voice. Most of the calibration plots look nothing like the example ones from the release notes. And only a few mildly resemble the examples. Adjusting mic gain to about 70 seems to improve the audio. However, every time I key up, there is now an awful lot of noise before I even start speaking. Once I start speaking the audio is ok'ish with a load of background noise. I tried messing about with other SSB settings with no improvements. I did find a second electret mic that gave me similar results. I have now set it back to factory default and seeking advice. Any suggestions? Mel. M0KMD.
|
|
QMX+ low(ish) power output
Hi all, first off, thanks to Jeff Moore who helped my QMX midband, and noticed my silly mistakes. Second off, I've just finished a QMX plus and am fairly happy with it except for the fact im getting 2-3 watts, leaning closer to 2 on all bands except 160m. I've reflowed all LPFs, PA, and tri toroids. Any ideas on where to look next? I dont think i have any failed finals or shorts.
|
|
New Build, No Flash Drive found
31
#build
#building
#qmx
I finished the QMX7build and have applied power, No Smoke but also not seeing a flash drive, Steps so Far: Limited the supply voltage to 7V Limited Current to 350mA Applied power and did not see any voltage or current as expected. Pressed the Left Encoder and saw a voltage drop AND the mA jump to the 350mA limit Release button and the voltage returns to 7 volts and mA is back to zero. No USB Flash Drive shows up. Tried Pressing the Left encoder again, same results, Voltage drop and mA to 350 limit while the button is pressed. I have searched the group for steps to troubleshoot but since I don't have the firmware loaded I am not sure where to start looking. I have looked very closely for any cold joints or bridges or anything that looks out of place. Is there a guide I can use to help trace / Trouble shoot? Thanks Bill
|
|
QMX+ Volume
2
discovering more things on the rig. I finde, that the min. audio volume is still quite high but could not find a setting to alter that ( apart from muting it) -- Martin DK3UW
|
|
QMX+ Power Output Question
19
I finished my QMX+ kit 2 weeks ago. I built it for 9V, and held my breath as I powered it up for the first time. Everything seems to work fine, and all bands receive and transmit. I called CQ a few times on CW and saw typical results on the reverse beacon network. I have also worked some FT8 on various bands. So overall, I feel like it is a successful build. That being said, I do have a question about the power output. Running into a dummy load, I get the output as listed below. Are these figures typical on the higher bands, and if not is there anything I can do to help increase the output to where it should be? 73, Jim (w8ykg) 160M 5 Watts 80M 5 Watts 60M 5 Watts 40M 4 Watts 30M 4 Watts 20M 3.5 Watts 17M 3 Watts 15M 3 Watts 12M 3 Watts 10M 2 Watts 6M 1 Watt
|
|
Hey all! Got my QMX+ rev 3 last week and have had a blast assembling it over the past few days. Finished it last night, booted just fine, and was able to tune some CW on 10m with a big grin on my face ? The thing of it is - after a few minutes, it froze. The LCD contrast went a bit darker, audio output stopped, and all front panel controls had no effect. Unable to power off by holding the VOL encoder, I had to cut power at the source. A short time later I was able to boot back up, browse some bands, tune some CW, and then it freezes again. Same symptoms: LCD goes higher contrast, audio stops, all controls stop, have to cut power. I'm pretty new to debugging PCBs but figured I'd dive in as best I could to gather some info, and here's what I've been able to piece together: I wired it for 12V, and based on measurements my battery was delivering consistent 12.13V Contemporaneous with each instance of the board freezing was a drop from 12.13V down to 12.0V I checked a number of the components around the PWR_ON and PWR_HOLD circuits, and no blown components However, the measured voltage across R105 went from ~3V (normal operation) to ~4V (frozen) No smells or popping sounds like components faulting/failing No changes to the LCD indicating on-board protections or anything like that Tried running 9V in case there were unobserved fluctuations in my power source, but it was the same behavior - a few minutes of normal operation, and then freezing measured voltage during operation was around 7-8V I've tried connecting to the serial terminal to check the on-board diagnostics, and that seems to be the most consistent way to trigger a freeze. Without trying to connect a terminal, I can usually get about 2-5 minutes of normal operation between power cycles, but as soon as I attempt to connect the terminal, it freezes. Like I said, I'm new to a lot of this but eager to learn so forgive me if there's obvious debugging steps I've missed ? ??. But yeah, not quite sure where to go from here! Would greatly appreciate any help or pointers!
|
|
QMX Display Brightness
19
I am finding the brightness of the QMX display to be too high. I want to increase R306 (33 ohms) to lower that. I'm thinking about 100 ohms. Any other suggestions as to what would be a good starting point?. -- 73, Dan NM3A
|
|
VFO A and B
2
I just noticed a funny thing . My Logging software indicates the QRG and when in A&B it indicates VFO B and not the receiving VFO A. On transmit it then changes to the QRG of VFO A but transmits on VFO B. Is there a bug in the CAT ? -- Martin DK3UW
|
|
CW Filters
7
I just upgraded to the 027 firmware on my QMX, from 018. Being able to select the CW filter is very nice, but I don't understand how to enable cascading or compounding of two CW filters. The manual says there are two CW filters - 300 and 500 Hz, yet the submenu shows 8 filters, ranging from 50 Hz to 500 Hz. Thanks and 73, Steve, N2IC
|
|
Possible QMX/QDX PA Improvement Idea
5
It occurred to me that the Interface between the ACT08 drivers and the BS170 gates could be AC coupled. A quick simulation with 100nf and a 2k to ground on the gates shows no ill effects. The advantage is two-fold. First, a BS170 failure that puts 12V on the gates is less likely to damage the ACT08 outputs. Second, any failure that leaves the ACT08 outputs high for a long time is less likely to fry the BS170s. Just a thought. Tony AD0VC
|
|
Lin_reg_en
5
#troubleshooting
SO i had a working qmx rev 2 - purchased assembled - i was swapping my antenna coax from another radio and poof the QMX no longer powers up . I also had a kit so i swapped out the PS boards . Still no luck . i tested the power supply boards individualy and they work fine . After furthur trouble shooting i discovered that the Lin_Reg_EN signal is stuck at .7 volts with 10V in . I tried tacking a pull down resistor ( 10k ) to ground and it lowered it by maybe 20 millivolts . Sounds like i have a bigger problem . Any suggestions
|
Image Name
Sat 8:39am
Sat 8:39am