Hi all
I released firmware 1.01c with a change that should hopefully make it easier to debug problems with no transmit power. It basically provides more information?on the situation, via the status LED, which flashes?1 time, 2 times, or 3 times for 0.1 seconds, repeating every 1 second, to indicate status information.?
So here are the following scenarios and possible causes, when you hit the transmit button (e.g. Enable TX in WSJT-X) and the software indicates you are transmitting (e.g. the status bar in the bottom left of WSJT-X is bright yellow). I am assuming QDX VOX is disabled and all other parameters in QDX have not been modified (QDX configuration screen in the terminal applications).?
Status LED is solid on
QDX has not received any CAT command to tell it to change to transmit mode. In this case, you have to investigate how you have configured CAT; did you select radio "TS440", and click the button for PTT method?"CAT"? Remember sometimes it might be called TS440S. And if that doesn't work, feel welcome to try TS480.?
Status LED blinks once, repeating every second
QDX has received the CAT command to tell it to change to transmit mode, and is now in transmit mode. However, there is NO audio. Possible causes:
- You have not selected QDX as your output device in the PC software's settings e.g. in WSJT-X.?
- Somewhere in the sound settings of your computer, the sound channel that routes to QDX is muted somehow
Status LED blinks twice, repeating every second
In this case, QDX has received the CAT command and is in transmit mode; there is also audio coming through which indicates that you have correctly selected QDX as the sound output device in the PC software's settings e.g. WSJT-X. However, the audio level (volume) is too low. The actual key-down volume threshold in QDX is by default, 80% of maximum. This is a setting in the QDX configuration screen but there is no known reason to change it. Possible causes for the problem:
- The volume slider in your PC software application is too low. For example, the volume slider which is at the bottom right corner of the WSJT-X screen. The recommended setting is full volume and there is no reason to use lower than 100% full volume (QDX cannot over-modulate, or splatter, and the power output is not reduced by lowering the volume, only by reducing the QDX supply voltage).?
- Somewhere in your PC settings, some sound mixer somewhere is reducing the volume being sent to the QDX output device. In Windows there is a sound mixer. Perhaps somewhere there is an AGC enable which is reducing the volume. Maybe that makes sense if you have headphones plugged, to protect your ears, but not?when you have QDX plugged in.?
- There's also a key-up threshold which defaults to 60%; when the audio signal falls to below 60% of maximum, QDX will key-up. There's no reason to change this setting in the QDX configuration screen, but if you did, and if you chose a key-up threshold which is higher than the key-down threshold, then this will stop transmission, it will always key-up regardless of the volume.?
Status LED blinks three times, repeating every second
Then QDX really, really does think it is transmitting output power. It's absolutely sure of?itself. CAT has turned on transmit mode, there is audio streaming through the USB connection, and the volume is sufficient to cause key-down.?
In this case, there is probably a hardware fault. Check enamel on toroids (properly scraped/burned off to get a good electrical connection and DC continuity through the low pass filter, output transformer etc as described in the manual). Check for shorts between turns of the output transformer. Check for any connection issues to your power meter.?
Is your power supply up to the task? Remember that at 9V it may use around 1A; for 12V builds, around 0.7A.?
Is it a switched mode power supply? Some of these particularly produce glitches, noise, and don't like RF etc. I prefer linear power supplies just on the basis of one-less-thing-to-go-wrong. And anyway they help warm the shack in winter.?
Also check that when you replaced the 47uH SMD inductors, you got proper connections to the correct tracks, and that you did not accidentally break any PCB tracks.?
Other comments:
If you get dropped CAT connections or audio USB connections, then this could indicate RF problems in the shack due to an unbalanced antenna system - which cause common mode feedline current issues - different from high SWR - in which case you may need an RF choke on the feedline (I use 10 turns on an FT240-43 ferrite toroid) and/or clip-on ferrites or ferrite toroids on the USB cable and/or power cable.?
It seems that there is a greater tendency for people to have trouble with Windows computers though maybe this is just because a greater percentage of people are using Windows. As you know, I was a loyal Windows servant for a 1/4 century until two years ago. But you know... they kept making new versions of Windows and every time I got more confused; and fortunately the mind and body heal themselves quickly and tend to remember the good things and forget the bad. So I am not much use now, advising on Windows sound issues... but I hope there is some collective expertise here that can assist people with problems.?
I hope this new version 1.01c provides an extra diagnostic tool that can help resolve or at least narrow down problem areas.?
73 Hans G0UPL
Shirley Dulcey KE1L
Julian N4JO
Darryl Hambly