Re: New qmx transmits on digital for a millisecond
Update, I wound my rg316 coax through a green core of unknown material from Ali express with ten turns. And bought a shielded 18" USB cable and put 5 ferrite clamp ons and it works fine now. Sorry it took so long to update, just got around to getting it on the air in digital modes. Thank you all for the excellent suggestion.?
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Larry
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Re: Severe QMX+ audio distortion
I agree with Stan on this. All of my QCXs and QMXs have great audio. It's possible to make them distort with maladjusted AGC, but if you set it right, or turn it off, the audio is great. The QCXs benefit from a 1K ohm resistor on the wiper to make them a bit more linear, but the QMXs digital volume works great.?
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73, Dan - W2DLC
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Re: QMX+ Rev1 Not shutting down
Thank you very much for your clear explanation. Based on a few other posts, this is what I thought might be happening, but didn’t know what to check. Will give it a whirl tomorrow and report back. Many thanks,
Scott
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Re: LCD Display error on new assembled QMX?
Hi Joe
To test the theory, try pressing that area and see if it displays correctly. The one on my Sony took a while to sort out, but the ones used on the QRP Lab radios are usually easy to fix.
Good luck
Ted?
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Re: Severe QMX+ audio distortion
That is not my experience with the QMX/QMX+ audio.
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When I use a reasonable quality earphone (I have some very old Apple iPhone earbuds with the 3.5mm plug), or when I use my Heil headset, the quality of the audio from my QMX audio jack is excellent.? Surprisingly so.? It is quiet and clear, with no discernible distortion, SSB or CW or digital modes.? Even a cheap pair of earphones I bought before boarding an airline flight produce very nice audio.? I would say it is exceptionally good, considering the low cost of this kit.??
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When I hook up a cheap powered external speaker, the audio is good, but not nearly as good, and easily distorts at higher volumes.? I understand from others that they have external powered speakers that work very well.
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The QMX audio output is designed for earphones/headphones.? Measuring it via an audacity recording may not give it a fair representation, since the audio input to most computers is designed for a high-impedance microphone, and may not present the expected load impedance.? Having said that, I will also say that I have measured my QMX audio via audacity recording, after carefully setting the levels (QMX volume setting and computer input setting), and it does not look distorted like what you show, so there may indeed be some fault with that particular QMX+, or with the recording setup details.
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But the bottom line is that my experience with both my QMX and QMX+ is that they produce excellent audio, and that your message title of "severe QMX+ audio distortion" is certainly not what you can expect from this design.
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Stan KC7XE
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Re: New Built QMX screen lit but blank
#help
#qmx
For what it is worth, I recall the contrast pot on my QMX+ kit was all the way to the stop to show perfect contrast. My preference would be near the middle of travel but hey! That is a low priority when there are other tweaks like seeing if GPS clock works, playing with PuTTy to see disappointing power out because I wound the T501 the easy way, etc. Stuff like that!
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73
Karl
KI4ZUQ
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Re: QMX+ Audio not working on Linux
Fixed it! It was because I had IQ mode on..
Still nothing, I set the gain to 70
Oh, you have to delete the numbers, I'm dumb
Lol, I can't figure out how to change the numbers on the band configuration, what keys do you use??? arrow is for moving and +, -, and numbers dont work
On occasion, I've found that a new audio device's input/output levels are set to zero, regardless what an associated program may indicate. Try using alsamixer to set the levels.
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Al, K2ZN
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Re: QMX+ Audio not working on Linux
Still nothing, I set the gain to 70
Oh, you have to delete the numbers, I'm dumb
Lol, I can't figure out how to change the numbers on the band configuration, what keys do you use??? arrow is for moving and +, -, and numbers dont work
On occasion, I've found that a new audio device's input/output levels are set to zero, regardless what an associated program may indicate. Try using alsamixer to set the levels.
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Al, K2ZN
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Re: QMX+ Audio not working on Linux
Oh, you have to delete the numbers, I'm dumb
Lol, I can't figure out how to change the numbers on the band configuration, what keys do you use??? arrow is for moving and +, -, and numbers dont work
On occasion, I've found that a new audio device's input/output levels are set to zero, regardless what an associated program may indicate. Try using alsamixer to set the levels.
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Al, K2ZN
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Re: QMX+ Audio not working on Linux
Lol, I can't figure out how to change the numbers on the band configuration, what keys do you use??? arrow is for moving and +, -, and numbers dont work
On occasion, I've found that a new audio device's input/output levels are set to zero, regardless what an associated program may indicate. Try using alsamixer to set the levels.
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Al, K2ZN
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Re: mission impossible? QRP labs QMX power supply boards
Hans,
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Understood.? I would not recommend modding the QMX for most builders either.? Significant hacks are way more likely to trash a QMX than the few incidents of SMPS failures.
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Chris wrote:? "Are the PCM1804 failures down to momentay voltage spikes?"
Hans replied:? "There's nothing to indicate or suggest this."
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There are lots of PCM1804 failures though, would be nice to get to the bottom of that. My impression from following this forum is that PCM1804 failures are mostly on the QMX, not on the QDX which has linear regulators.? I could be wrong in that.? If true that at least indicates something, though is by no means definitive.
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Many have trouble with momentary shorts of the power supplies given the minimal clearances. Would be interesting to evaluate how one of those standalone 5v SMPS boards recovers from a momentary VCC short, will need a processor working the ADC_5V and PWM_5V signals.? I'd expect to see a spike.
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If we do decide to change the QMX+ power supplies, an easy retrofit is to solder a daughterboard down to header pins on JP105, plus the firmware mod to inspect for a short from LIN_REG_EN to ground at initial power up.? Daughterboard could have linear regulators or switcher IC's.? If the daughterboard is tested before shipping and the mod is kept as simple as a board install and a solder glob across two Sot23 pins (I'm good at that), should be an easy enough upgrade for most kit builders.
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Jerry, KE7ER
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On Sun, Dec 22, 2024 at 01:15 PM, Hans Summers wrote:
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Hans is now recommending 220k instead of 100k in parallel with the 22k at R112 and R113, for a resultant value of 20k.
And Hans is correct, you lose the rather nice power-on/power-off scheme.
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I don't recommend the mod at all; but I'm saying if you insist on doing it, then you need some kind of ADC voltage somewhat higher than half the rail voltage so that the processor thinks it's SMPS control loops are all working OK and it can proceed past waiting for the supplies to come up. 100K, 220K, it isn't terribly critical.?
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73 Hans G0UPL
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Re: QMX+ Audio not working on Linux
On occasion, I've found that a new audio device's input/output levels are set to zero, regardless what an associated program may indicate. Try using alsamixer to set the levels.
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Al, K2ZN
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Re: QMX+ Audio not working on Linux
It's worth checking whether you saw this recent thread: /g/QRPLabs/message/135756The thread pertained to somewhat similar symptoms experienced by a Windows user. The solution, suggested by Greg McCain, was "Use Putty/terminal program and bump up the value of the audio output in the band configuration screen."
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Re: Computer not connecting to newly built QDX
Yes Sam, I've tried three different USB cables and two different computers and all have the same problem.
Used these same cables to connect and load firmware on a QMX+ I built last week with no problems.
I think it's a defective chip on the board at this point.
Gary a.
USB issues always begin with the cable.? Be sure to test with a known good working cable.
Sam? (Happy QDX operator on 20M WSPR @ W4SSC)
I just finished building a version 5 QDX unit.? The build went very well and I'm sure there are no poor solder connections as I checked every connection with a VOM after doing the soldering.? All were good.
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This is a high band version and the third QDX kit I've built.? The first two work fine.?
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The problem I'm seeing is when I connect to the computer port I get a message that something is wrong with the USB device and Windows will not recognize it.
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It does appear the unit is working otherwise as the red LED blinks rapidly at power on and then stays lit.? I'm unable to load any firmware until I get the USB port to recognize the QDX.
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I wired this unit up for 12 volts and used the RWTST method to wind the Binocular core.
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I'm sure someone else has had this issue so what has been found to be the cause(s) and fixes for this problem?
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Gary A. - W0MNA
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Re: QMX+ with Macbook Air (Sonoma OS)
Stan, I am aware of how the QMX+ works with
Windows.? Unfortunately it does not work that way on a Mac? I
wish it did. It is really too bad as this machine's form factor
is great for portable work.
MAC is essentially a Linux driven OS and does not
have the concept of native com ports.? It is my understanding
that it takes a USB to serial adapter with drivers.
What I said above may be heresy as I am a new Mac
owner testing the waters.? Finally, all I am really looking for
is a Mac friendly ham comm program that I can control freq, mode
etc.? N1MM won't work as it only runs on Windows.? It can be
made to run on a Mac but not without a windows emulator like
WINE. That is way too much work.
After looking around I see there are a number of
programs that will run on a Mac for hams I was just testing the
water here as to specific users of MACS and ham radio software
to control the QMX+.? Not looking to operate digital at this
time, just CAT and CW with a logging program.
Thanks,
Joe K8FC
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Re: QMX+ Audio not working on Linux
What does it saynon the input and output under the audio tab?
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73, Dan - W2DLC
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Re: QMX+ Audio not working on Linux
Thanks for the reply but that did not help, I have everything turned up. It is weird because it shows up but no sound goes in but it does go out.
Oops, Sorry, I failed to note that you are using Linux.
Same issues apply, but it is the Linux control for input audio that you need to adjust.? This depends on your flavor of Linux.
Hopefully someone else can help with that...
Stan KC7XE
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Beautiful job!
Will you share the stl files or sell them?
73, Larry K3PEG
Happy Holidays!
Finished my QMX+ a while ago and finaly got time to designe and print the enclosure.
Case is designed with future expansions in mind presented with removable accesories platform to be used for battery atu etc.
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Small foldable legs, bigger vfo button and slightly larger af button for better ergonomics.
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Re: mission impossible? QRP labs QMX power supply boards
Hans is now recommending 220k instead of 100k in parallel with the 22k at R112 and R113, for a resultant value of 20k.
And Hans is correct, you lose the rather nice power-on/power-off scheme.
I don't recommend the mod at all; but I'm saying if you insist on doing it, then you need some kind of ADC voltage somewhat higher than half the rail voltage so that the processor thinks it's SMPS control loops are all working OK and it can proceed past waiting for the supplies to come up. 100K, 220K, it isn't terribly critical.?
73 Hans G0UPL
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Daniel Conklin
Ted 2E0THH
Karl
Al Scanandoah
Todd W2TEF
dxradio33