Not sure if the may be the cause of what some people are seeing, but I have noticed that when I click stop in WSJT-x 2.5 the QDX stops working.? I have no determined if the QDX is causing the issue or if the USB connection is at fault.? simply restarting WSJT solves the issue.? More investigating to come.? Will try to determine what CAT command if any is sent via the stop button.

I get this with some antenna configurations but there is no GPS connected. The 40m QCX-mini operates normally when the “G” is not present.?

Ideas?

Thanks for the info Hans. I was able to find the root cause of my failed finals issue (my fault). It was a bad solder job on one of the 80 m toroids. Since it was an open, when I transmitted it had no load. I replaced the BS170s and IC5 and am now on the air. First contact, 1600 km on. 40m.?

--
Jginaz

On 16/11/2021 17:07, Retired Doc wrote:

So, I plugged it back and found that I am sending 5W at 750mA on 20M.? Made 1 Q in the US and PSKReporter says I am getting out across the US and into

Kent,

That could well be a bad soldered joint, most likely on one of the wires of the inductors.

73 Alan G4ZFQ

开云体育

OK, back on line.? open the box and did not find anything.? Measured the BS170 in-circuit and found these values for them on my old M3 Analyzer.? It gave both of the values indicated, which I don't understand.? So, I plugged it back and found that I am sending 5W at 750mA on 20M.? Made 1 Q in the US and PSKReporter says I am getting out across the US and into Europe.

I have not put the case back on so I don't know if that is part of the issue, but will do that later today.? Appreciate any suggestions about what I should be checking.

Kent KC9LIF

On Mon, Nov 15, 2021 at 11:30 PM, Hans Summers wrote:

That's an academic point anyway. Since you never stop paying for it, the scenario never arises.?

Almost rolled off my chair laughing at the truth of that. Fortunately XYL is in the kitchen in a Zoom mtg, so I won't have to explain what I was laughing at.
?
--
Julian, N4JO.

Hi, Conard,
Backlight control didn't enter the picture until v1.06. but if your unit boots up showing "v1.05" - irrespective of what's printed on the chip label, you don't have that capability.
Yes, if the label says 1.07a the display should show 1.07.

Do you have the capability to update your firmware yourself?
--
Julian, N4JO.

On 16/11/2021 15:46, Alan G4ZFQ via groups.io wrote:

It seems best to leave it for half an hour, then there is a better chance of correct initialisation.

There is a voltage maintained for quite a while, over 3 volts on the electrolytic, 2.5 volts in places on the board.
I'm thinking it needs a resistor or two to drain this away.

开云体育

The next step would be to get some snapshots of what the OS thinks it has connected

Andy,

Is this what you are asking?

The QDX fault condition here is that when the audio does not seem to be configured correctly.
My last test first showed a bad audio trace, then the very high noise output started. Often when monitoring the audio in the fault condition giving bad audio/RF it sounds a rough unstable noise. The high noise output situation is just that, a giant white noise.
This often appears to be triggered by powering up the QDX soon after it has been running correctly. Then quite a few attempts are required to get it working properly. Various linear power supplies tried.
It seems best to leave it for half an hour, then there is a better chance of correct initialisation.

I do not think this is USB connection related?

Two file attachments to save yards of text.

There is also the CAT dropout problem which may well show up something in USB test. Maybe later.

73 Alan G4ZFQ

When the embedded STM USB sound card is detected by Windows does it set 'correct' bit depth/sampling rate?

Al

The 24 bit 48KHz is reported to the OS, no alternative.

73 Alan G4ZFQ

Pretty much what I figured. Thanks!

73 /paul W3FIS

Hi all,

I searched but couldn't find if this was already discussed, but it's another audio thing to keep in mind when using pulseaudio (the default on many Linux distro's).

Today I was watching the JS8Call waterfall and wanted to listen to my own transmission with another transceiver, the IC-9100. This TRX also has a USB sound card and is connected to the same PC. Then I saw the waterfall change as I turned the RF-gain on the IC-9100?! I had the correct QDX sound card selected in JS8Call...

Here's what happens. Pulseaudio automatically switches the audio to the last connected device. This comes in handy when you connect USB head phones, the audio will then automatically be routed to your headphones.

I tried to disable 'module-switch-on-connect' first, but I had to comment 'module-switch-on-port-available' also in /etc/pulseaudio/default.pa (and restart). Maybe others can exchange their experience with these settings?

### Should be after module-*-restore but before module-*-detect
#load-module module-switch-on-port-available

### Use hot-plugged devices like Bluetooth or USB automatically (LP: #1702794)
.ifexists module-switch-on-connect.so
#load-module module-switch-on-connect
.endif

In the screenshot below you can see when it went wrong. I have the correct sound card in JS8Call configured, but the volume control (pavucontrol) now shows another sound card, not the QDX. You can also see the change in the waterfall. This problem seems to be solved when commenting out the switch modules as above.





73, Ben
PA2ST

Potential buyer here,

When the embedded STM USB sound card is detected by Windows does it set 'correct' bit depth/sampling rate?

I've been reading over the QDX Instruction manual's circuit description, and I think it is 24-bit @ 48kHz. Sometimes Windows assigns 16-bit @ 44.1 kHz by default.

I'm guessing that if there's a mismatch it's not going to cause big troubles. But, is it a setting that needs to be addressed when connecting the QDX to a Windows computer?

Thanks!

--Al
WD4AH

?

Andy,
The trials that I have done do not point to a USB audio issue.? There is something disturbing the QDX that causes it to go into a state where the opposite sideband is not being suppressed as reported by the Audio Filter scan.

Based on the comment from Ben, PA2ST, and his screenshots I tried starting the QDX without the antenna connected and then ran the Audio Filter sweep.? The sweep came out correctly.? WSJT-X started correctly and then decoded signals.? I repeated starting with and without the antenna connected 3 times one after the other with a wait time between.? In all three starts with the antenna connected the sweep showed the opposite sideband unsuppressed.? In the three starts without the antenna connected the sweeps were good.

I checked on my Icom 7300 and the noise level on the 40 meters band was very high.

Based on the above, I think it would be back to Hans and QPR-Labs to try to work out what causes the QDX to lose the discrimination of the sideband when started with high noise on the antenna.

In the meantime, I would request that others try the experiment and see if they can repeat my results (true scientific method ;-)

73
Evan
AC9TU

开云体育

On Tue, Nov 16, 2021 at 11:15 AM, Ben wrote:

Great tip though! I'll let JS8Call run for some time into a dummy load to see what happens.

Unfortunately disabling USB auto suspend did not solve it for me. After a while the RX audio level was zero, JS8Call was in TX mode but the QDX not. And the audio and RF filter sweep looked as below. Keep the tips coming though :)

- A 1 minute power down did not help, same weird sweep output.
- A second 1 minute power down did help! Filter sweeps looking OK now.

Besides hunting down this problem I had a nice QSO with someone in France this morning, so I'm going to have a bit of QDX fun now :-)

73, Ben
PA2ST


Audio filter sweep in the fault state

RF filter sweep in the fault state

Hi All,

Everything was working fine, and then I switched firmware 1.01c.? When I loaded it up the QDX LED turned off.? I removed the power and then plug it in and the fast flashing occurred as usual and the QDX files looked ok.? So, I did not think much about.? I was able to have normal output, which was 5W at 740mA.



However, this morning when I turned it on, I was only getting about 0.5W which was drawing 1.34A, I suspect that something went wrong.? I opened the case and there is not a blown BS170 like before so I can't immediately discover any problem visually.

I wonder if anyone has an idea what the problem might be?? I am a real dunce with troubleshooting and don't want to make things worse.? I also am reading the section on the PC terminal emulator, but? I? have not tried the PC terminal emulator yet.

Thanks, Kent KC9LIF