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To further clarify Hans’s point on this QDX PA mod with FDT86256, ?I did this pa mod as an experiment to see if FDT86256 will work in QDX as a PA mosfet.?

It is NOT created as a fix for QDX PA! It is just an experiment of curiosity and I published my findings.?

73

Barb WB2CBA

I think it would be more indicative if the first vertical bar for PWR and SWR would be fixed and would consequently mean 0W and 1:1 respectively.

73 Bojan S53DZ

I don't know, because it says that the normal is 1 business day for kits. I will have to wait I guess. Thank you for your responses, 73.

After upgrading, the SWR threshold in my radio was set at 255 and could not be changed via the front panel. A quick factory reset restored things to normal.?

I tested the radio on a quick SOTA activation yesterday evening and the new SWR and voltage display features were excellent. Thanks for your hard work, Hans.

Cheers,
Ronan
MM0IVR

"SWR:
-Seems to work pretty well. Slight increase with increasing frequency. 1.2 at 80m, 1.4 at 20m into dummy load that is less than 1:1.1 thru 100 MHz. '

Hi Dan,
could you please tell me what dummy load you are using?
I think you have a non-inductive dummy load, which results in it not moving away from 1:1.1 even at higher frequencies.
Several people had comments about swr. Although none of them talked about the quality of dummy load they use.
It follows that the fault is not with the firmware or the device.
--
Gyula HA3HZ

Hey Hans, great upgrade to the QMX.
Here are some observations:
- Maybe it is a good idea to move the Hardware tests menu in the last position, so you can access it with single ccw turn of the encoder and then swr tune should be on the first position, as it is used the most.
- Sometimes when transmitting already stored messages it got messed up. Additional dit or dat are transmitted inside the message.
- When using the tune swr function on the device, the swr starts jumping up and down and i have to restart the device to have a steady reading again.

Great work on these devices. I just love my qcx mini and qmx.
73 de LZ3OM

Hello,

I think that this is a great idea. It could also be done with JS8call which would give greater flexibility as on top of self spotting, it would be possible to give your position or even drop a short message.

73,

Yannig - F4IUJ

This is a feature request for the QMX.

Sending special FT8 messages that trigger the spotting system enabled by sotamat.com would make the QMX a killer rig for back country or off grid SOTA and POTA activators.

The “normal” method of using sotamat’s FT8 spotting system involves using an app on your phone to play a specially encoded FT8 message while you hold the phone next to the radio’s mic during an SSB transmission. ?The app cycles through several transmissions of the coded message, each transmission at different audio offsets to increase the odds of the message being picked up by a skimmer and forwarded to PSKReporter.

I would like to be able to enter the coded message as a text input into the QMX, then while in the field, trigger the transmission of the message like I would a CW memory message, only here the firmware would compute the FT8 tones/frequencies.

If the QMX could do this then I wouldn’t even need the app running on my phone to initiate a SOTA spot.

Here is information about sotamat?
and here is a very short , 2 minutes, video on sotamat?

Hans, I hope this feature is something you might consider for a future QMX firmware release.

73 de Matt

This post by Chris G5CTH has been mentioned several times.
/g/QRPLabs/message/106787

To follow the instructions you'll need a voltage-controlled and current-limited power supply.? You do need accurate, adjustable voltage.? You will want to be able to monitor the current.? Can you get away without a current-limiting power supply?? Yes ... as long as nothing goes wrong.? If you don't connect anything to the regulated output voltage terminal, the board should draw very minimal current.

You will be taking the place of the QMX microprocessor, providing the necessary voltage signals to exercise the functionality of the power supply boards.

You could -- cautiously -- connect a resistor between the board's output terminal and board ground, to see that the board can source some current.? Choose your resistor so it limits current to quite a low value, just to see it work.? On the 5V board, if you wanted to see 10 milliamps of current sourced by the board, use your V=IR rule and compute 500 ohms.? I doubt there's much value in doing that experiment though, and there is the risk of fumble-fingers shorting out the output and killing the board.? My risk / benefit analysis says don't do it.? Be happy with the voltage checks that Chris has shown us.

Remember that with fully-functional power supply boards, your radio can still be damaged by other mistakes.? Like Hans says in the assembly manual (Section 2.31, FINAL CHECKS BEFORE APPLYING POWER THE FIRST TIME), give it a GOOD examination with magnification, to rule out shorts, solder bridges and the like.? Find the things you forgot to do.? Check the areas he tells you to check.

73

Another development that might be telling - I just connected and the diagnostics very quicky upon boot, and it shows the errant measured supply voltage and VCC by by the processor ramp up in voltage over the course of several seconds. It starts out as good, and then voltage creeps up. Is this suggesting a processor issue? I instrumented the "ADC_BATT" line and it holds steady at about 1.7V which is what I calculated as expected value for a 10V supply.

Long press of the Tune knob usually takes me into the Messages, like a double click would do, rather than letting me move the VFO cursor to larger or smaller tuning rates. Also, occasionally single clicks are interpreted as double clicks even though I’m nowhere close to clicking within the 300ms double click threshold.

Jim,

For any potential buyer - it may be salvageable, particularly now that there is a third-party MOD kit available to replace the self-destructing PA!

73

Terry

See:?

Thanks for the suggestinons! I spent some more time probing around and testing things as well as reflowing the pins to the SMPS boards. I've noticed now that the VCC line is at 5.6V, so I believe for whatever reason the zener is clamping it. Can anyone help me with some measured voltages around Q108, Q106, and Q112? I see both V_IN and +12V reading about 10V as expected, so it appears there is some issue at the 5V supply.

It also appears this is somewhat intermittent. I was able to boot the radio up, connect to the terminal, and diagnostics read everything correct, but then a few seconds later the terminal lost connection and I saw the same contrast issue on the display.

Hans,

Thanks for the updates. Great to see things progressing. Here are a few observations FYI:
First, I am mainly looking at CW operations, so haven't really looked at FT8 or other modes.

RIT:
-Occasionally will not turn off and remains on screen with just the offset numbers, not the 'RIT'. Does not always do this and I can't figure out what causes it. Sometimes only could get rid of it by turning off radio or pulling power.
-RIT tune rate is at 10Hz (as in manual picture), not 100Hz as manual says.
-Cannot change RIT tune rate with the hold and turn encoder. It always switches to the main tuning and changes that rate.
-A or B VFO reset to 0,000,00 a couple of times. Not sure what set it off.

A/B Operations:
-While playing with A/B ops, both A & B VFOs occasionally reset to 0,000,00 MHz and once QMX locked up. Could only get out of it by pulling power - i.e., no buttons worked, including power down. Not sure how I did this, either.

Messages:
-Custom splash does not work with message 11 or 12. Not implemented yet? No big deal anyway.
-When SWR protection (setting 3) is on, interrupting an automated message frequently triggers SWR protection. This is into a good dummy load or a reasonably matched antenna. If it is interrupted during key down, it almost always triggers it. If you time it between characters or words, it does not always trigger it.?

Factory Reset:
-Request going back to enter '17' for reset rather than press TUNE. Altho I haven't done it, it would be just too easy to reset it accidentally.

Volume Control:
-After updating firmware, I got minimum volume for a good while (maybe a minute) no matter what I did with the volume encoder. Seems okay now except as below.
-At times volume control works opposite of usual- i.e., CW lowers volume and CCW raises it.?
-Minimum to max volume often over a very small angle motion; less than 90 degrees and sometimes this repeats multiple times in a single encoder 360 deg turn.
-I know you are working on this and AGC. Hope you get it done soon, as I find my QCXs are much nicer for CW and I usually take them or my TR-35 for portable ops due to the volume control oddities.

SWR:
-Seems to work pretty well. Slight increase with increasing frequency. 1.2 at 80m, 1.4 at 20m into dummy load that is less than 1:1.1 thru 100 MHz.?

--
73, Dan? NM3A