Wow Hans,?

Congrats, awesome, fantastic...?

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Will the internal microphone work with the official firmware or is this a subject to be done in another Firmware update!?

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73 de Matt, DL1SER

Hi Yoon

The quality ain't too bad, actually ok but,

there is a squealing low level noise in the background. Thanks for the info because I could use that in an emergency. Very convenient so I would like the Mic kept in any future board revision!?

Best 72,

George?

Park US-3843 today, central NC. Low humidity after yesterday's storms. ?Slight breeze.?

QMX built for 9w

Dork regulator DROK Adjustable Voltage Regulator...

Bioenno 9v battery

SOTA Beams Bandhopper

Palm pico paddle

Why I love this rig: even though it is menu-driven, it seems SO INTUITIVE that it doesn't seem difficult to do what I want. ?Hans must have done some serious human factors analysis with the rig.?

Also, the receiver is outstanding.?

I made 24 QSO in 45 minutes on 20. The beacon CW message capability is superb. ?

Thanks to all for the Drok regulator suggestion.?

And thanks to Hans!!

thanks Tony, could you tell me what number on schematic is this transistor? I will check for shorts etc...

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73 de Marek SP9TKW

On Sun, May 4, 2025 at 08:17 PM, Ricky wrote:

The one everyone is using is -25db could this be the issue.???

Ricky, I guess yes. Using the default settings only some peaks of your voice are coming through. If you would set Microphone gain much higher you would add a lot of noise.

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You may read this SSB settings.

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73 Ludwig

I have QRP-Labs build QMX mid-band Rev.4 f/w v_027 which is blowing finals. So far two sets, third set in.

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Transmitter Voltage is showing in RED to start with.

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Here are diagnostics screens

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After pressing "P", screen changes to this

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And after pressing "T" screen changes to this

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Off course all into dummy load.

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Calling few CQs into dummy load, I can see that finals get very warm and familiar smell is being emitted.

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As I said two sets of BS170 have been already smoked. Any pointers what to check.

Display SWR reading seem correct as well as output power.

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Please help.

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73 de Marek SP9TKW

On Sun, May 4, 2025 at 02:20 PM, Martin+HB9GVW wrote:

An idea: what would be an addition is an audible SWR indication in case the tuner is a few meters away from the QMX, eg progressively longer dashes if the antenna is too long, short dits if the antenna is too short. In the range of say SWR <1.5 a continuous tone is heard.

I didn't think this through. Just sitting on a frequency with a given tuner setting gives you an SWR, but doesn't tell you on which side of the optimum you are. Only by changing the tuning knobs you can know whether it's getting better or worse.

There should be an indication as well to the actual SWR and as to improvement / deterioration when you change the tuning.

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73 de Martin / HB9GVW

Jim,

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I'm having the exact same problem, after calibration on the latest firmware, I have low power out on all bands, 20M is just 1.2 watts now, 40M is just 2.8, yet 80 is 4.8 watts. The power output seems to be all over the place. I too am waiting for a resolution.

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Joel

N6ALT

Additional info: this is with 1.00_27 firmware. I'm not trying to use the SSB beta yet.

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I have an odd situation here with my 12V QMX+. I could transmit normally on all bands with a 9V power supply. But at 12V when I transmitted on 12m (24.910 MHz) the current draw was quite a bit higher than on the other bands. My power supply's current limit was set at 1.0A and it hit that. All other bands drew less than an amp. After transmitting at that frequency the receive current had jumped to 300 mA (previously about 100 mA) and all the other bands transmitted about half the output power they had before.?

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I replaced the finals and it happened again. Transmitting on 12m at 12V caused a failure in the finals. (Possibly Q507 as well. I get no RF output at all on any band now.)

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Any ideas on what might cause that one band to zap the finals? I've looked over its lowpass filter and don't see any visible shorts, and the inductors have the correct cores and number of turns. I was able to transmit on 10m before trying 12m and it seemed to work, although with less power out than the other bands.

So built the qmx with no issues? installed Hans latest firmware completed full calibration. CW tests were fantastic no issues.

BUT! Ssb is not behaving. Built the small electret microphone and tested with quite a lot of distortion tried various adjustments up and down to no avail.

I have a suspicion that it may be the electret which is -50db . 1-10v

The one everyone is using is -25db could this be the issue.???

I can't source the -25db one here.

Currently doing another recalibration.

Any suggestions are gratefully accepted :)

TNX Yoon !? What was your input setting. External mic? I tried it but not with those settings...will try again ....

I already made several SSB QSOs only with the internal mic, no external mic plugged in. Fwiw, here are my settings:

73,

Yoon KM6KJI

Mine does that too. I thought it was normal. I haven’t noticed a problem and the protection definitely works if I get to the level I set(3).?

im still on v3 of firmware as I have had a chance to keep up. ?Radio working great and got many New England QSO party contacts from my backyard last night.?

will be interested if others notice the same behavior.?

Presumably like the speed to fly setting, with quiet band when the antenna is ideal.

You will have likely confused some people on here who will say a variometer is one rotatable wire coil inside another?

Folks, prior to going to the most recent firmware on one of my QMX+ rigs, I ran PuTTY and documented my power out into a dummy load on each band. Then I installed the 2.0 firmware and ran another PuTTY session, noting the power - it was exactly the same.

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Last night I ran the calibration procedure - geeze, that took forever! Anyway, after doing that I did a mic gain adjustment and went up to the 40 meter phone band. OMG - a bazillion stations - the 7 district QSO party in full swing! Started adjusting my manual antenna tuner and noticed that my power output was much lower than it had been. Looked like less than three watts now. Tried calling a station but no reply. So, I fired up my recently built WA3TFS 20 watt amp and was successful working several stations before calling it a day.

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This morning I started PuTTY and checked power out on each band. Sure enough, the result was that each band is now showing 50 percent less RF out than before. Not cool. I was thinking about doing a factory reset to see if that would cure the issue. Or going back to 0.027 firmware. But that would mean doing that hour long calibration routine again at some point.

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So, any thoughts about this problem? Have others seen this after doing the calibration run? And if so, what was the resolution?

--

Jim / K7TXA
Eagle, ID

SKCC 10447T
BUG 301

The internal Mic doesn't work. But let's not throw out the baby with the bath water.

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To this end I built a little simulator to test how a "Little Hole" works and if that can be retained in a future revision of QMX.....or if it is a bad idea.

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In short, I drilled a small hole 1/16" hole in plastic box about the same size as a QMX and placed a working mic in the box.?

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To my delight the laws of air pressure worked and not only does the result sound good, it may even be better than a foam muff. It tends to buffer the sound.

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Hans had a good idea, he just? 'F'? up the design. No shame there, we all do that. The real shame would be discarding the IDEA.??