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In diagnostic on pc it shows 0 watts?

srw 1.2 on my 40 m dipole

Karl, these results are a bit confusing to me.

If I understand, you are putting in a 14MHz sine wave signal at about 15mV, and are tuned to 14MHz.

With that setting, you should see the 14MHz signal at the input of IC408, pin 5, and on its output, but only on pins 1 and 2.? The true output is on pin 1, and it gets coupled through the shared BPF L403 to pin 2.

You should not see the signal on IC408 pins 3 and 4 or anywhere else.? If you do, you likely have a short somehow between L401 and L403, or perhaps a failed IC408.

And the signal should also be seen at IC402 pin 11.? If it is on IC402 pin 11, that would be from the above-stated short.? But since you see it very weakly or not at all on pin 11, it means something is wrong with your soldering or winding of L403.

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The signals you are measuring on IC403 pins 7 and 9 shouldn't be there, or perhaps are from poor grounding during measurement.? And I don't think they are at all related to your input signal, if it is indeed a 14MHz sine wave.

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So check L403 carefully, and any possible shorting to L401.

Stan KC7XE

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Interesting.??

Mine doesn't do that (tested in SSB mode on both a QMX and a QMX+ into a dummy load).

Sometimes at the instant of pushing the PTT key, the SWR indicator does jump up, but then goes back down and doesn't continue to change.

Testing instead into an antenna, which shows 1.3:1 on the Hardware test / Test SWR function, I see the swr indicator go up one or two 'bars', which is correct, based on the operational manual's definition of an increment of 0.2 per 'bar'.

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So I'm wondering what is different in your setup that changes the behavior?? It's almost as if you are looking at ALC or mic AGC rather than SWR, but I don't think it is supposed to be able to do that.

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Stan KC7XE.

Everything seems good?

when tx 0 watts jumper in?

were do I start to trouble shoot?

The operations manual states the following, which looks much like your display (with the exception of the CW):

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During the actual WSPR message transmission, the display shows something like this:
14,097,140 122 2
G0UPL IO90 37
The elements of this display are explained as follows:
14,097,140 Transmission frequency (tone 0)
122 Current symbol is 122 (of 162 symbols making up a WSPR transmission)

2 Current tone being transmitted (one of 0, 1, 2 or 3)
G0UPL Callsign encoded into the transmission
IO90 5-character Maidenhead Locator square, encoded into the transmission
37 Power in dBm, encoded into the transmission

And also:

The beacon function can also operate a CW or FSKCW (slow narrowband) beacon.

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Perhaps you have enabled the CW function of the beacon??

No, you don't need to do the calibration process.? In that case the phase and amplitude corrections are simply not performed, and you will still get reasonably good results.

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If you do the calibration process, you may transmit better audio.? The calibration process is detailed on the qrp-labs page where you access/download the beta firmware.

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Stan KC7XE

On Fri, Apr 4, 2025 at 03:52 PM, pgramsey, N9LFF wrote:

I've sort of convinced myself that I have a shorted Q504, drawing too much current and heating up Q507

I think you are correct, based on the evidence stated.? Did you perhaps leave your QMX in tx mode when you turned away??? Extended tx time could have burned one or more finals at full voltage/power.? You can try measuring resistance between the leads of Q504 (and the other three BS170s).? Mine shows in-circuit S-D resistance of about 6.8k.? The resistance between G and S or D varies depending on which polarity I connect the probes - but always over 150k.

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On Sun, Apr 6, 2025 at 10:58 AM, Jared N7MAW wrote:

For those that are using the K6ARK mics, what is your required mic gain?

This greatly depends on the particular mic element you get.? The one I received (from one of the kits Erik kindly provided) has much higher sensitivity and dynamic range than any of the others I have tried so far.? I could set my gain at about 58, and the noise floor in the QMX microphone test?is only up about midway into the second 10dB column.?

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And Erik told me this is from an inexpensive bag from Amazon, 10 for a few dollars.? He says there is a range of performance levels in a bag of these, so your experience may vary.?

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I have ordered the same element Hans used for testing to compare its performance.? It is a bit more expensive, but likely tested to its specs.

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Stan KC7XE?

For those that are using the K6ARK mics, what is your required mic gain? For mine, it is almost +70dB, which seems really high according to the wiki page. I am getting a lot of audio distortion with my testing and I'm trying to debug this.

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73, Jared, N7MAW

Bravo. Thank you. Great testimonial with graphics.?

I just discovered a slight change.? On 6m, the Bias SMPS current is about double at ~8.2mA.

Repeat and expanded, explained tests:

Point? ? ?Result

BNC? ? ? ? ?good

IC408

? Pin 5? ? ? ?good

? ? ? ? ?1? ? ? ?good

? ? ? ? ? 2? ? ? good

? ? ? ? ? 3? ? ? good

? ? ? ? ? 4? ? ? good

? ? ? ? ? 6? ? ? ? no

? ? ? ? ? 7? ? ? ? no

? ? ? ? ? 8? ? ? very weak

IC402

? Pin? ?9? ? ? very weak

? ? ? ? ? ?10? ? weak

? ? ? ? ? ? 11? ?noise

? ? ? ? ? ? 12? ? ?no

? ? ? ? ? ? 13? ? ?no

IC403

? Pin 7? ? ? ? ? ? ~55 mhz*

? ? ? ? ?9? ? ? ? ? ? ~55 mhz*

* very strong signal - twice rms of input (see picture)

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73
Karl
KI4ZUQ

Hello all,

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Finally got the time to attach the QMX to the computer and I found interesting stuff... :

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This is what it looks like TXing when the voltage is about 11V, nothing wrong apart from the supply voltage reading wrong by 0.2V

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When I get the Voltage down to 10.8V, this is what I get and "interesting" stuff happens, namely the supply voltage is wrong by 1V, the 5V SMPS voltage is too high and the transmitter voltage is too low :

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When I get down to 10.7V not TXing, even ,more surprising stuff happens, the supply voltage is completely wrong and on top of this the 5VSMPS gives us a very high reading which might well be true(ish) as the screen becomes darker :

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My instinct would be the 5V SMPS is shot and weirdness ensues but I am not sure of myself at all! May be the overvoltage protection kicks and switches off the QMX. For reference, I destroyed one of the SMPS last year and replaced the 2. In theory they should be good....

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Any help welcomed !

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73,

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Yannig - F4IUJ

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No good. :( I redid the loop connecting the SWR bridge to the BNC connector and the results are still the same.

Yes! CESSB on. I did the standard calibration per Hans’ directions and set up the mic with the tool in terminal.?

I just got back from the Pacific NW robotics district championships where N7BIN and team were competing.

There are a couple parks just off the highway near Spokane so took time for POTA on the way to/from.

I noticed a couple strange things with the 1_01_003?firmware on my QMX rev 2.

Despite this, and the challenge of 5W SSB with a low antenna, the activations were still a lot of fun.?

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73, Mike KK7ER

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On Sun, Apr 6, 2025 at 05:03 AM, Muhsin TA1MHS wrote:

YES!?5.5 x 2.5mm?plug?works with me

Some 5.5x2.5 plugs may work.

But you inherit extra risk of intermittent power connection, which for some users has resulted in damage to their QMX internal power supply.?

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The QMX/QMX+ power input is designed for a 5.5x2.1 plug.

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Stan KC7XE?

Just for a bit of clarity… Turkey is not on the current list of tariffed countries. Further, never send your SS# or any other personal identifying information over email. Email is not secure.

Hi Nico,

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FWIW, I see the same thing.

The SWR reading bounces all over the place but the SWR protection does not trip.

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73, Mike KK7ER

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