Make sure the USB cable is attached to both your QMX and computer BEFORE you turn on the QMX.? This is important.

Then activate the firmware update menu.

When doing so, in some cases (for some unknown reason) the QMX may turn off and the USB storage device will not pop up.? If this happens, simply press the power-on button, and the USB storage device should then appear.

After dragging the new QMX firmware file (make sure you unzip it first) to the QMX USB storage device window, the QMX should reboot after a few seconds into normal mode.? But sometimes (again for unknown reasons) it again powers off and doesn't auto-reboot.? If this happens, just press the power-on button again, and you should be operational with the new firmware.

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These failures to reboot during the firmware update process seem to happen on specific QMX units, so if it is happening on yours, it may always happen.? I have one that does that, another that reboots properly.

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Stan KC7XE

I find this terminal to be absolutely simple, it just needs to be run on a Chrome based browser.

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Joel

N6ALT

On Wed, Mar 26, 2025 at 08:35 AM, Petrov Sergey wrote:

not all will be ready to learn how to work with Terminal program

Sergey, the terminal interface is very easy to use.? I encourage you to try it.? If you need some help, send me a message and I'll walk you through getting it set up.? Most here use puTTY, and its setup interface can be intimidating, and is definitely non-intuitive (I have used it for years).? Instead, for QMX I use TeraTerm, which is much more friendly.? Or the old Windows Hyperterm is also easy.? ?After a one-time setup to select the serial port, all it takes is plugging in a USB cable, opening the terminal app, and hitting the enter key.

Stan KC7XE?

Or may the contacts should be activated for TX by default? 5V on the ring and ground on the tip during TX.

Hello Hans! Is it possible to add activation of PTT output contacts (5V on the ring during TX and so on) to QMX standard menu (not threw Terminal program)? I think it makes sense because almost all sooner or later will want to try PA with QMX, but not all will be ready to learn how to work with Terminal program just for this simple procedure )

Main menu -> Configuration -> Band configuration and then go in and change band settings as needed. Section 8.5 starting on page 78 in the QMX manual describes in more detail, but only shows via the terminal interface. The pinot for the 3.5 mm connector is important.

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I do not have Terminal program (( Is it possible to do this threw QMX menu??

There was a screenshot above that shows it, I will repost it here. You need to enable it on each band you plan to use.?

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Thank you Jim! Were exactly in menu can I enable "key to ground"?

Interesting observations on this thread.

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Despite being CW only I am also an inveterate fiddler? ( it is ain't broke you're not experimenting hard enough :- ).

I loaded each of the recent software loads (from Linux desktop ) and all but one went well except for one which required shorting pad 2 to ground to forces dead device back to DFU mode and then reload.

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After a calibration ( don't do this late at night when you are due to go to bed as it takes a while !! :-) ) I had dreadful distorted audio.? Thinking it was perhaps an issue with me driving from an external source ( USB), I found a near on 40-year-old electret I used to have as a neck harness for mobile 2M FM in the early 80s and wired it to a 3.5mm terminal break out ( see below - these are great for quick patching speakers/mikes/keys / ptt siwtches ).? I did test the electret first in a PC sound card and it sounded great.

Still with terrible distortion, I switched off the phase and amplitude predistort and the sound was then fine.? ?I was wondering if this was owing to calibration done on v...2 and now on v...3 ( seem to remember this is written to EEPROM so this should not be an issue). I re-ran the calibration and the audio is now fine.

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73 Simon

Hello Sergey,

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My QMX+ seems to have neither issue you are reporting. I am driving a Juma PA 100D clone successfully with SWR protection enabled. To key the amp I had to go into the menu to enable the key to ground feature in the band settings.?

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73,

Jim AC9YY

On Tue, Mar 25, 2025 at 06:09 AM, Glenn S wrote:

I settled on a 20m centre frequency of 14300000 which produced a smooth descending plot although not with as many points as say, 17m.

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I played around with my band setting for 20 last night, and the plot did not change with much significance.? That said,? I have been able to Tx with good audio after re-running phase, and USB calibrations before messing with the band configs. Plots looks strange, but "it works"!? I did end up leaving Freq Center slightly adjusted, but all others the same.??

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Plus PTT output doesn't work properly. Nothing changes there when I start TX.

BR/Sergey

UB3AZK

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Hello Hans! Looks like there is a bug with SWR measurement during usage of PA. QMX detects very high SWR during TX threw PA and stops it (if protection is switched on). In reality SWR is 1.1 (confirmed by Hardware test of QMX itself + Nano VNA).?

BR Sergey

UB3AZK

I agree that would have been easier... but it's done now LOL... I agree, if I need to do it again, that's the plan.

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I am happy to report that the quadruple BS107 transplant seems to have been successful :)

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Running the calibration now... hoping for the best.

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73,

Joel W9JFK

When I use my Hermes Lite 2 or a Tiny SA it appears that my audio goes way beyond 3 KHz on USB for example both above and below my center frequency. However checking on a remote WebSDR I see what looks like a clean well defined SSB/USB signal and all my audio reports have been good.

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73,

Jim AC9YY

I wouldn't worry to much. Hans wrote regarding the calibration "The results are markedly different by band, this is normal. " and "Some phase error measurements do have weird glitches."

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73 Ludwig