Ok thanks for the reply. It was a talent cell battery with a regulated 12 volt output. I did have the battery meter turned on and it was 11.6 - 11.7 volts.?

I will wait to hear back from the qrplabs ticketing system.?

Arne, check solder joints from T507 to the board.

73 Ludwig

Hi Roy,

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I try to keep paper free where ever I can.

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When I was building my QMX+, I read off of the pdf document off of my laptop. I can highlight sections and make notes on the pdf, no problem.

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Cheers.

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Mel. M0KMD.

Hi,

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I wanted to tune my magloop antenna with the "Tune SWR" tool in the QMX+ menus, and no matter what I do with the antenna, the SWR never goes above 1.04 or so. That cannot be correct, as I'm using a magloop. Any tips on what I'm doing wrong?

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Thank you Stan for the support. I don't have smd welding equipment. I'm waiting for a response from Hans.?

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I presume you mean firmware version 1_02_000

Larry, You cannot enable the internal mic; you must use an external mic.? A future firmware version may (or may not) enable the internal mic.? Currently its A/D channel is used for necessary noise reduction.

Ken, In SSB mode,? with the two-tone input, the PTT works the same as with the microphone.? Alternately, if you are connected with the terminal program via USB, you can press 'T' for transmit/ptt with almost any of the SSB config parameters selected (including SSB input select).? When PTT is pressed, you should hear the receiver be silenced and see the two-tone power output on the power meter (if you have it enabled).? If you are using USB (CAT control), with VFO A showing, when you send the CAT PTT command (TX;) you should get the 'dot' or 'line' under the A that indicates PTT/Transmit, just like in Digi mode.? It would be kinda nice if this happened with the microphone PTT button, but it doesn't, so you have to rely on the silencing of the receiver and the power-output indication.

Stan KC7XE

I don’t know if I missed it in the manual, but how do you get the tx on when the two tone mode is selected? Also, is there any indication that the ext mic ptt signal is seen? I wired one up but pressing the ptt switch does not seem to bring up the tx bar indication, I would so love a big red light to say when the tx is enabled!

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73 Ken g4apb?

Ok I checked off the things on the list.

Got to Q516 and checked it in circuit. It was open which ever way I tested . Removed it and tested again. Same result.

So I figured I had nothing to lose and ran the terminal test for T and got the same results as I tested earlier with the Q516 in place.?

Unorthodox for sure but the loss of the Q516 had nil impact.

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I will replace the 817 and see what happens........

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@Steve ZL1SGS seems Jaycar have them in stock

On Tue, May 20, 2025 at 11:03 PM, Luke wrote:

what is the diameter of copper wire?

I have no idea, for that coil.? It is very thin wire.? I do know that I have replaced one of those coils on one of my QMX boards - it is a bit tricky since the contacts are on the bottom, so you have to use a hot air soldering tool.? I have a cheap one from Amazon.? I practiced on a different old electronics board until I got the hang of it.? If you want details, I can provide them.? I used the 331 inductor (330uH) in this kit for the replacement:

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So from your description it sounds like the upper coil end of the broken wire goes into the center of the coil; too bad - if it was on the outside layer of windings, such that you could unwind it a bit, that is a very easy fix.? Or if the end is accessible enough to tack-solder a jumper wire on - but probably not with the wire going to the inner windings.

Hi Stan, the copper wire seems to me to come from above and then go to be soldered at the bottom. Breaking the wire is compatible with breaking the edge, in that upper area of the solenoid the windings seem to be crushed. Question, what is the diameter of copper wire?

On Sat, May 17, 2025 at 06:28 PM, Eben Fourie wrote:

so tried setting both offset and sidetone freq to 600.....This does not seem to persist, when I go back into the menu, I see it has changed back to 700...

I have also seen this behavior, which is due to the firmware 'automatically' selecting compatible frequency/filter combinations.

Make sure to check out the CW filter description in the Operation Manual (pg 29 in v1.02.00 manual).

With 600Hz as offset/sidetone, only the 400, 300, 200, and 100Hz filters are compatible.?

So when I do filter/sidetone settings, I do this:

a) first set the CW passband to 'none' to deactivate any of the filters, so the 'auto' selection code doesn't change things

b) set my desired CW offset and sidetone (600Hz in your example)

c) in 'Choose filters', I enable only the compatible set of filters (400, 300, 200, 100 for your 600Hz tone)

d) then I go back and choose the narrow filter, and choose the CW center corresponding to my offset/sidetone (e.g. 600Hz).

Then the offset/sidetone selection seems to stay put when I select one of the filters using the CW passband setting.

I can even then go back and enable additional filters, and it keeps my setting for the 'compatible' filters, but auto-shifts the setting to a compatible offset/tone for the other filters.

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Stan KC7XE

Wow - I've never heard that one before.? Just make very sure it is not moving because of a loose wire connection; that could cause a failure later on.

You are correct, that 160m LPF sweep looks fine.

So the problem is most likely in the input side of the bandpass filter for 160m.? These are the connections I referred to in my prior post.

Since all other bands are working correctly, this is about the only place you can lose only the 160m signal.

All communications to Hans regarding specific orders/problems need to be done via the support system at qrp-labs.com, if I understand correctly.

No, the QMX definitely should not have failed after a short time of just listening - the exception being if the voltage on your power supply was way too high, e.g. 14V instead of 12V.? (Some fully charged so-called 12V batteries are really 14.4V or 13.8V - these should not be used with QMX without a voltage reducing circuit of some sort.)

But there are also possible 'infant mortality' parts failures that just happen - such failures are reasonably rare, but they do happen.

Please see the reply I made to your other post for some measurements to take.

Stan KC7XE

Wow, that's bad luck.

The measurement of the antenna/ground is as expected - it is a DC short, but RF passes fine.

The measurements I would take first are some voltage and current measurements.? The current measurements are particularly instructive:

1) Power supply voltage.? If you can vary the voltage, set it to about 7.5V for the remainder of the measurements.? If you can set a current limit, set it to 250mA.? This will avoid any potential further damage.

2) Power supply current with QMX powered off

3) Power supply current while pressing power-on button

4) Power supply current after releasing power-on button

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Also read the 'startup' page on the Wiki so you know the sequence of events as power is first applied to QMX:? /g/QRPLabs/wiki/36878

All of the above data will help you communicate the details of the problem to Hans, and to you and us if you want to try and fix it yourself.

Stan KC7XE

Thanks for having a look Stan and for the suggestions and recommendations.

Yes, noted the preinstalled caps.

I will certainly take a look at the suggested reading material and have another good look around.......

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Cheers

Ian ZL1HIM

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On Tue, May 20, 2025 at 08:11 PM, ZL1SGS wrote:

/g/QRPLabs/topic/107821803#msg127488

Hi Steve, Interesting read, thanks. Hopefully I can find a resolution.....
I think last time we spoke I was using the QMX..

The coil is fine as-is.? The chipped top does not affect functionality.

If the diode is working, there is no need to change it.? But it is a common 1N4148, so easy to find and replace if needed.