On Sat, Mar 29, 2025 at 10:26 AM, @Ludwig_DH8WN wrote:
On Sat, Mar 29, 2025 at 01:17 PM, Brien - KE7WB wrote:
Plug in the USB cable from computer to QMX and then try to turn on QMX.? This yet to be fully understood scenario worked for me on a couple of occasions.
Brian, if this works when you can't switch on your QMX without the USB cable something is wrong with your setting / your QMX!!!
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73 Ludwig
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Ludwig,
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Possibly, but it has not happened to mine for quite a while (so no opportunity to explore further) and my QMX has been working fine.? I did add some ESD mitigation and have not had any abnormal operation since.
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Re: Multibanding the 50w amp question
Thanks Gregg,
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I could totally go that route as well. This is just for CW, and it's good to hear the values for the LPF kit worked for you (I already bought the bigger toroids and higher-rated caps). Say, I'm sure I could look this up using the search function, but while you're here, what kind of output did you get on 15 meters? 73, Sam
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Re: Multibanding the 50w amp question
Sam,?
One other thought ...
Another 50W AMP kit plus the nice enclosure is just under $46 plus shipping.?
I ordered three and the shipping was the same as a single kit. Built one of them for 15m using values from the QRP-Labs LPF kit information with? purchased capacitors that matched the V Max Specs of the 50W supplied components. I also researched turn windings for the kit supplied toroids to get close to the inductance suggested for 15m.? Made good contacts on FT8 and WSPR.?
And just in case,? the 50W kit is not a linear so SSB is likely not going to work.
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Re: QMX+ high pitch noise on power. Now dead.
It is a bit hard to test a zener, especially a low-voltage one in circuit.
I just measured mine with the diode test function of my multimeter, and it measures 0.31V in one direction, and 0.44 volts in the other.
I don't know what that really means, but if yours is broken, you will likely see something different.
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The way I have normally tested D109 is to remove it, then power on and see if the rig wakes up normally.? If it does, I know that D109 was bad and replace it.? I do NOT recommend you do this, because you have no current limit on your supply, and D109 will not be there to protect your processor and other 3.3V devices if there is still a problem.? Instead, I would replace it before trying to power on again.? Then if there is still a problem, D109 will conduct the over-voltage to ground and not harm your other ICs.
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D109? is very small and nestled between two other devices, so be sure you have the practical skill (practice helps a lot) to replace it before trying; otherwise send it to someone else to fix.? I can look, I may have an extra one I can send you if you don't have one but do have the skill to replace it.
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Stan KC7XE
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Re: Figuring out why no keyer sound and updating my QMX Menu Reference to Firmware 1_01_003
Sorry, I didn't mean to send you down a long rabbit-hole.? I have no idea how to make airspy work, either.? Someone else here used NaP3, and posted the way they set it up, and that's what I have used.? So if you ever want to try again, maybe search these messages for NaP3 and use that approach, or post a message asking for a program and setup that work nicely with QMX.
Stan KC7XE
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Re: Multibanding the 50w amp question
Thanks Nate! Well, this looks promising. I was also considering just building a 20-meter amp and being happy with external filter for 30 and 40 meters, but of course a little extra on the higher bands would be nice. I'll just have to do some research on the highest band I can pull off then. Also, while that board might not work I appreciate you sending it along.. I like the idea of using relays to interface with my rig for automatic band switching so fortunately (unfortunately?) this project just got more complicated. best, Sam
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Re: 74ACT08 damaged and LCD is all blocks
Not installing the BPFs/LPFs shouldn't cause a problem.? You should disable TX for those bands in the band config menu, otherwise it is risky.? Accidental TX when the band is selected or running any of the Hardware test tools or SSB Calibration on those bands may cause failures, since they won't be terminated correctly.? So I hope those bands weren't included in your SSB Calibration; in its beta condition who knows if it is honoring that TX disable setting.
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I purchased a couple of very inexpensive (Ali express) "USB&DC Digital Tester"s (mine are Atorch brand) that I always connect inline with a new power source before and while initially using it with my QMX.? It shows voltage and current, and also the PD and QC protocol triggering status when on a USB port.? It has both USB and 5.5/2.1 digital in/out ports.? So I can be confident of the voltage before I plug it in, and watch the current while it starts up.? I highly recommend something like this.? It sounds like the combination of your trigger cable and that one charger were not doing what was expected.
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Stan KC7XE
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Re: Figuring out why no keyer sound and updating my QMX Menu Reference to Firmware 1_01_003
I just spent hours at trying to get airspy working it will not connect. Don't worry I do not expect anyone to try to explain it online. :)? It was just a curiosity thing if it would work.? Just wanted to try it. Thank you for mentioning it though. Your off the hook.??
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Re: Multibanding the 50w amp question
Sam, I think others have found that without changing ferrite materials, output above 17m is pretty poor, if it works at all. If you look up some threads about 10m builds of this amp, the changes are discussed and laid out.?
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To answer your question, there would not be significant sacrifice. Some rigs are set up this way, where the highest LPF is always in line. I've had considerations of doing the same, making a 40-15m amp.? Currently though, I have a 50w amp built for 20m, that I have run on 40m with an external 40m LPF added in line. Output on both is as expected.?
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One LPF board to look at/consider:
The 3 band LPF version is only 5cm x 5cm! Problem is that I'm not sure that a 5 pole LPF would be enough with this Class C amp, especially if covering more than one band with that LPF.
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-Nate?
N8BTR
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Re: Figuring out why no keyer sound and updating my QMX Menu Reference to Firmware 1_01_003
A bit complicated to set up at first, but then just plug-n-play.
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Multibanding the 50w amp question
Hi all,
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I have an unbuilt 50-watt amp kit and I'm trying to figure out how to best build it. I just completed a 5-band (40-15 meters) homebrew rig (it's not a QMX, but it works!). I'd like to use the amp on multiple bands for this radio (and possibly a QMX). I am thinking of just building the amp for the highest band I need and adding a switchable external low-pass filter.
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But I had a question: obviously the output of the amp won't be as large on higher bands. However, if I build the amp for 15 meters and transmit on say 40 meters (with a 40 meter external low-pass filter) should I still similar output as I would get if I built the amp for 40 meters, or would there be a significant sacrifice running though the 15 meter filter first? I'm sure some of you have experience trying this out. Thank you!
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72, Sam WN5C
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Re: Figuring out why no keyer sound and updating my QMX Menu Reference to Firmware 1_01_003
On Sat, Mar 29, 2025 at 12:07 PM, Stan Dye wrote:
Actually, for CW mode, you can connect the QMX to your computer, enable the I/Q mode, and use SDR software as a panadapter,
That sounds interesting for when using at home, but complicated.
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Re: Should I just go ahead and order a QMX+?
N9LFF
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The QMX plus is clearly a mature design for cw and digital modes. I delayed until I had time to build it, on my bench now. Best to not be in a hurry during assembly. If you are ready to build, order it. Have a plan B for Field Day to take off all pressure. Enjoy the journey.?
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Curt
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Re: 74ACT08 damaged and LCD is all blocks
Oh Stan,? you embarrass me.
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Re: 74ACT08 damaged and LCD is all blocks
Hi Ludwig and Stan,
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I'd definitely check BS170 as well. Once removed from the PCB, IC503's Vcc to gnd seems to be open, so if it was causing short, it would have to be done via BS170 I guess?
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I'd provide some more context. I finished building this QMX+ a few days ago. It had good TX/RX. Power output on 20/10 was a bit more than 4W. Compared to my previous QMX HB build, its MDS is 10dB better and its SSB tx from mic doesn't have the constant 2kHz tone in the background like my QMX HB does. I was very satisfied with its performance. I believe the BS170s had been working fine before. This morning I was setting up the shack for WPX and I wanted to power it with a dedicated USB-C charger with 12V PD trigger. I tried a few times to turn it on from that 40W Anker charger without success (LCD went off after showing "Initializing audio..."). A few minutes later, when powered from the known good charger/battery, it started to have the symptoms I described in the original post. So TX was never attempted with that suspicious 40W charger. I'll check BS170s later today. I do have lots of new BS170s - I ordered them last year with PCM1804 and 3253. Maybe I should order SS14, D108, D109 as well just in case..
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PS I didn't install the BFP/LPFs for the 160/80/60 bands. Not sure if that's gonna cause problem.
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73 N6HAN
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
On Sat, Mar 29, 2025 at 05:00 PM, @Ludwig_DH8WN wrote:
On Sat, Mar 29, 2025 at 08:10 PM, Pawe? H wrote:
software glitch
Pawel, I'm not sure about software. I'm also not sure about ESD. Maybe it is a unstable PCM1804. There are reports about PCM1804 working wrong related to temperature. Maybe here something is similar.
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73 Ludwig
I think that's possible too. After several hours experimenting with band configuration settings and calibration settings, my QMX+ suddenly started screaming in my ear on one band and developed a little digital sounding irregular beeping noise on certain other bands. After I let it cool off over night, it seems to be back close to normal, but I noticed that the audio noise levels seem to return to max volume on some bands when I cycle through them. I suspect some damage to the PCM1804 because the symptoms seem similar to others who have had PCM1804 failures.
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73, Dan - W2DLC
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Re: Should I just go ahead and order a QMX+?
I think we have already gotten this year's big new thing from QRP Labs, in the form of the SSB update.
To speculate on the new thing for 2026... perhaps a QMX XL? Something with a larger display and a more base-station-like configuration?
Gwen, it is already listed on the website, see the link in the left-hand column under the QMX+ heading.
It is complete with the beginnings of a detailed description, and what to expect.
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My two cents:
It is unlikely that you will risk your QMX*, but a very small handful of people have reported hardware issues after installing, that disabled their QMX until fixed.? It is not fully known whether those hardware problems were the fault of the update, or due to pre-existing conditions, either internal to QMX or external in their setup, that may have been exacerbated by the update.? So if you want to avoid that risk, wait for another beta update or two, or for the full release.
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Most of us have had no major problems, but there are still some bugs and quirks in the new SSB mode and getting it configured and working as well as it should on all the bands, that affect a good number of users, but not all - it may depend on your particular QMX.? And those are what generate most of the messages recently in the SSB-related threads.?
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And many of us have successfully found workarounds to the issues which Hans has not yet fixed, such that using SSB has been great fun on our QMX*!
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Stan KC7XE
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Just had my first QSO.? A local ham.? Received a good audio report.? I was using the QMX+ and my "Tiny Linear".? The Tiny Linear is a 100W-capable homebrew unit.? It is in a box only slightly bigger than the QMX+.? It doesn't need band codes, you change bands manually with a touch screen.
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? To make it work, I had to modify the QMX+ a bit.? There is a 220-ohm resistor in series with the output switch for the PTT.? That was too much resistance for the Tiny Linear, which actually runs its T/R relay through its PTT input.?? How much
current?? The output switch of the QMX+ is rated 170mA.??? OK, I forget how much the linear sources, so I measured it...17mA.? So I pulled the card out of the QMX+ and shorted across the 220ohm resistor.
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Seeing 60W out on peaks.? Enough to be heard.
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?????????????????????????????? - Jerry, KF6VB
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Re: QDX Transmit Power Drops
Thank you for your responses and yes that makes sense. I wasn't thinking about how mosfets behave when overheated. I checked all the solder joints and ohmed out Q8 - Q11, T1 and L14 to see they had continuity where they were supposed to have it on the circuit board. I suspect I have either wound T1 incorrectly or I have scraped some enamel off the wire and it's shorting to an adjacent wire or the core. I am considering rewinding it with fresh wire if I can get it off the board without damaging it. I'm open to alternate suggestions. ?
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73 Doug WB5WRC
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Re: QMX+ high pitch noise on power. Now dead.
The output of the IC101
is 0V before pressing the button, then briefly goes to 3.2V, and then to 1.7V when I press it. When you press the button input starts at 12 then goes down to 10 then 8.
+V, Vcc, and Vdd are all zero without pushing the button. When pushing the button. +V = 12V. Vcc = 160 mV. Vdd = 1.6 V
Resistance to ground: +V = 25 K Ohms Vcc = 3.68 K Ohms Vdd = 202.4 Ohms
Vcc to Vdd = 1.4 K Ohms Vdd to +V = 18 K Ohms Vcc to?+V = 18 K Ohms
Is there a way I can check D109?
Thanks for all the help!
On Sat, Mar 29, 2025 at 12:10 PM, Nico Smith wrote:
On IC101 it goes to 3.2 then 1.7 volts when. I press the button.
It draws 0.7 amps when pressing the button.?
0.7A is way too much, about 3x normal, confirming something is shorting.
Also, on JP106, there is no power.
I don't quite understand your description of the voltage measurement.? Are you looking at the output pin of the IC101 regulator (the one closest to the diodes and coil)?? And it is 0V before pressing the button, then briefly goes to 3.2V, and then to 1.7V when you press the button?? Or is it 3.2V before pressing the button, then goes to 1.7V when pressing?? Or are you looking at the input pin (closest to card edge)?
It is useful to know the voltages on both the input and output pins of IC101 both before and while pressing the button, and after releasing the button.?
Also please the voltages on +V, Vcc, and Vdd before and while pressing the button.? These are found in that order, in JP105, adjacent to D108 and C107 - they are the inner set of the two rows of 3 small holes.? (Vcc and Vdd are also in JP106, where you say you saw no power, so they may show nothing again).? If there is truly 0V (or very close to 0V) on Vdd while pressing the button, you likely have a shorted D109 (i.e. it did its job in protecting from overvoltage), and hopefully no damage to the processor or other 3.3V parts.
And one more set of measurements: with QMX+ unplugged, measure the resistance between +12V and gnd, Vcc and gnd, and Vdd and gnd.? Each of these should be a few k-ohms.? Then measure the resistance directly between each of the three voltages.? These should all be very high, in the mega-ohm range.
These measurements will help diagnose where the problem is, and if there are other problems besides the likely D109.?
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By the way, looking at your setup - I would buy an inexpensive 3A drock boost/buck converter, set it to 12.0V output, and wire it into the cable coming from your power supply to your QMX+.? That way you can leave the power supply set at the best voltage for your Kenwood, and still always have the correct power set for your QMX+, ensuring power mistakes don't get made.? And depending on which model you buy, it will have a current limit you can set while debugging.? (The current limit may only work if you don't ground your QMX directly to the Kenwood, due to the design of the drok, but that's easily avoided during debug).
Stan KC7XE
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Brien - KE7WB
Paul K7VIQ
Daniel Conklin
Shirley Dulcey KE1L