Back to measuring and checking. I have all the tools and no excuse now.

Thanks for any explanation or reference to a easily understood answer.

just a quick and quite possibly ill-considered thought ..

?

.. would it be possible and useful to have a sidetone frequency shift as the SWR changes?? E.g. the lower the frequency the better the match?? Stepped tones perhaps.

?

73

Rod

G0VKV

With the config CAT keying "Elecraft" its work fine. Many thanks Stan for your help.

Andre F6APU.

Thank you Stan, that was very helpful and exactly what I was hoping for. I think I should be able to fit the Conductors in.

Unfortunately, after checking everything in the package again carefully I didn't find the capacitors in the knobs or other components.

But now I'm happy because I can at least finish the build to see if it will turn on.

?

73, Dennis DM4NTZ?

73 de IZ2BHP.

Yes, looks like it is not correct to use Nano VNA for impedance measurement for PA. Thank you! Is it possible to measure imaginary and real part of impedance for PA in some other way?

I am currently organizing a group buy for PCBs only:

?

On Thu, May 22, 2025 at 04:54 AM, Roelof Bakker wrote:

In N1MM+ RUN mode and RIT on, the up or down key changes the frequency 10 Hz and no more, irrespective of the RIT tuning step setting.

The CAT monitor receives this: RD00010;? The LCD frequency read-out on the LCD changes from - 0.010 to +0.010 and vica versa.

It looks like the N1MM / QMX+ communication in RUN mode is restricted with RIT on.

This is because N1MM/Kenwood TS480 CAT implementation expects the RD00010; and RU00010; commands to be relative increments; on QMX they are implemented as absolute up/down offsets.

And note you can change the 00010 to a different value in the N1MM+ configurer; mine is set at 00020.

Furthermose, in RUN and RIT on, after using the up / down keys, RIT can not be switched off on the radio. Reverting in N1MM to S&P this works again.

I do not see this on my QMX+.? In either RUN or S/P, I can completely control RIT on the radio, and in RUN I have the minimal control discussed above.? And I can always turn RIT on/off with the control on QMX+ or the control on the bandmap in N1MM+, and adjust it using the radio's control.? I am running latest QMX firmware and latest N1MM+.

Stan KC7XE

Did anyone out there notice that FlexRadio is now copying QRP Labs? Not really, but their latest product (the Aurora series, announced right around Hamvention and scheduled to ship in 4Q25) is using EER?(aka polar modulation) generation of SSB. They worked with K1KP, the developer of the Polar Explorer that was demonstrated in 2019, to integrate the technology into a transceiver.

To be clear, I don't remember if the backlight actually did come on, as I didn't want to keep it connected to power any longer than I had to to check what the usb behaviour was (Up to that point the supply was set to act as a breaker as soon as an overcurrent event happened, vs supply limiting to a constant current which I did for the last tests). But the dark squares were very distinctive

Hi Stan

To #1, the DC plug isn't shorting, and the tab you mentioned isn't contacting the small transistor next to it

To #2, resistance of PWR_ON and PWR_HOLD to all other pins in that connector:
With PS #1 disconnected: PWR_ON to all >2Mohm, PWR_HOLD to all > 1Mohm, usually around 1.2M (I can get precise values to pairs if needed)
With PS #1 connected: The readings in this section aren't super stable, I think the meter I've got at home is suspect. Values are what they seem to settle to, initial readings are much lower
PWR_ON - PWM_5V : 50K
PWR_ON - Vin : 95K
PWR_ON - PWR_HOLD : 220K
PWR_ON - ADC_5V : 120K
PWR_ON - Vcc :? 130K
PWR_ON - +12V : 150K
PWR_ON - GND : 130K

PWR_HOLD - PWM_5V : 200K
PWR_HOLD - Vin : 310K
PWR_HOLD - ADC_5V : 105K
PWR_HOLD - Vcc : 100K
PWR_HOLD - +12V : 120K
PWR_HOLD - GND : 90K

To #3, I've created a facsimile out of a picture from the operating manual, imagine the blue squares are the colour of pixels on the display


I won't be able to do any power on tests for the weekend, as I don't have access to a current limiting supply at home, and I'm absolutely not plugging this into a battery until I've figured out what's up.

Thanks, Kait VA3KBY

On Fri, May 23, 2025 at 07:54 PM, Daniel Walter wrote:

I use a current and voltage limited supply when first testing kits

Current limiting can only do so much; a semiconductor can be destroyed WAY faster than a power supply can limit current; besides whatever energy is in the circuit or in the power supply's storage elements (capacitors) already, has already been provided and is available to assist in the damage.

Often the overcurrent event is a symptom of the failure, not the cause.? Semiconductors make excellent fast-blow fuses.

73, Don N2VGU

Functionally it will work fine for you to finish assembly and start testing.? Those capacitors affect only the bandpass filter and two low-pass filters.?

But check carefully first: things fit very tightly in QMX, and after installing toroids, etc, there will be very little working room to install the capacitors.? So look at some photos and get a feel for this to make sure you think you can fit them in before you move ahead.

?

And note that it is very, very rare for one of Hans kits to be missing parts.? Those capacitors can hide in the recesses of the knobs, or alongside other parts.? So look very carefully again; you may have them.? I found one of my 33pF caps inside of one of the knobs, and another hiding in the bnc connector.

?

Good luck,

Stan KC7XE

I had a 1% resistor sample kit whose resistors marked 10K were actually 1K.? I had some head scratching figuring out why the gains of my opamp circuits were all wrong.??

73, Don N2VGU

Here are a few questions, observations, checks to do, and resources for you to look at:

1) First a couple of checks based on your photos (the resolution got stripped, so it is hard to tell whether these are issues or not):

?? a) check the back end of your DC power plug.? It comes very close to other surfaces; make sure it is not shorting

?? b) on your PS board #1, verify that the big 'tab' on the lower large transistor is not contacting the drain lead of the other small transistor that is very close to it (ohm-meter check)

?

2) Now a question to verify what I think you reported: you say that your main board + just the PS#1 board installed, as shown in your photo, draws current when attached to the power supply, with nothing else done on your part?? This should not be able to happen, and indicates a malfunction somewhere, since the power should require switching to turn it on.? Likely possibilities are

?? a) the PWR_ON line is grounded (or attached to some signal that is grounded),

?? b) the PWR_HOLD signal is somehow pulled high, rather than low per its pull-down resistor

?? c) some failed component on the power supply board.

The first two of these, a) and b), can happen via that 2x4 connector - these signals are adjacent to others in that connector that could cause the fault if shorted, either on the PS board, or main board.? You should be able to test with a multimeter during power-on the voltage on these two lines, and with power off the resistance between these lines and any others in the connector - they should have very high resistance to all other lines.

And don't raise the current limit above 250mA until this is fixed, to avoid possible damage somewhere.

?

3) Another question for clarification: you said when fully assembled, the display turned on with a top line of black squares.? Did the display backlight come on? (hopefully not, this would be very mysterious).

?

4) Resources:

?? a) please see this entry in the wiki regarding independent functional tests for the power supply boards [and test your 5V board #1]: /g/QRPLabs/wiki/37128

?? b) please see this entry in the wiki to understand details of what happens as QMX starts up: /g/QRPLabs/wiki/36878

?? c) please see this newer QMX troubleshooting guide in the wiki [still a work in progress, links to other wiki pages]: /g/QRPLabs/wiki/39617

?

5) Another observation: since the QMX 'drive' appeared on your computer when you plugged it in, it indicates that PS board #2 (3.3V VDD) and your processor have at least basic functionality.? It may not hurt to load the firmware in this state.? You will likely have to manually power-cycle the QMX after it loads (rather than its usual auto-reboot),? but doing so will allow you to connect with the terminal and access all of the terminal diagnostics.? Those won't help with the above #2 issue, but will allow you to check many other things.

?

I hope this helps.

Stan KC7XE

?

I believe the excess wire is quite intentional, due to Hans' correct assumption that some will make mistakes and need a little more. Knowing I'd already wasted a foot or two of wire, I pre-cut lengths a bit shorter than the recommended length, so I wasn't throwing away a few inches away with each core. It all worked out perfectly in the end and the radio worked flawlessly with no fixes required. Actually, all four of my QRP-Labs builds have worked flawlessly, which I attribute more to Hans' excellent instructions more than my own ability.

?

Jack, thanks for the Kits & Parts link, that's going in my bookmarks. I'll look for your QST article but unfortunately the ARRL decided to not honor their subscription terms so I did not receive that issue.

?

Many thanks Stan for this infos. I will now tests with my qmx+ and fldigi.