Well, I guess I spoke too soon! ?VE3EGA, so much for maintaining status quo... (and you should buy a lottery ticket - you called it...)

Since repairing my QDX 24 hours ago (and making 20 FT-8 contacts on 80m - 20m over a few operating periods totaling about 3 total hours powered on and now utilizing the EMTECH ZM-2), my output power has dropped considerably as follows:

80m has gone from 4.7 watts to 1.8 watts
40m has gone from 4.9 watts to 1.5 watts
30m has gone from 4.1 watts to 1.7 watts
20m has gone from 4.8 watts to 1.4 watts

My measured voltage input is 9.16 volts DC utilizing a SoulBay 3V/4.5V/6V/7.5V/9V/12V Universal adapter rated at 2.0 A max.

The case had been getting pretty warm and I was about to take the suggestion above and measure the output with the adapter set to 7.5 VDC.

I've looked at Hans' troubleshooting guide and I believe that many of the "fixes" don't apply since I've made close to 400 contacts with this QDX and it had been working fine (likely not built wrong).

I've opened it up an reinspected it and nothing pops out at me. ?The search continues... ? ?ANY SUGGESTIONS?

73, ?Peter Schipelliti ?W1DAD Windham NH

I am using a Orange PI 800 which is a Chinese clone of the Raspberry PI 400 with the QDX.? The Raspberry PI 400 was not available to me.?? I followed the instructions in QDX manual and the work fine for JS8call.? In fact, I used the instructions for two other computers (old ASUS laptop, Raspberry Pi 3B+) and two different operating systems without any problems.?? I did encounter one problem with the brltty service.? But I did solve it,? I did post a message on this board, QDX with Linux with the solution. ?

John, you may need to learn about the package management system for the Raspberrian operating system.? The package management should be "apt".?? A search of the Internet, will turn up several good tutorials.? I found the terminal command "apt show package name (e.g. wsjtx or js8call)? shows what is going to be installed.

Sometimes, a library needed for the application is not installed.? I installed WSJTX first because I know it comes with HamLib.? I installed JS8call next.? I set up WSJTX using the QDX manual instructions then JS8call without a problem.? The QDX? with the Orange PI 900 combination has been working well.??? I hope this is a help.?

I think I'm missing something. This behavior is so bizarre: Purchased 1.09a chip from Hans and inserted into 40m mini. 5 watts out with 1.0:1 SWR into a dummy load. All good! Then tested on my dipole that has 1.2:1 SWR @7.020 MHz: 5 watts output, SWR 5.0:1. Replaced update chip with original Firmware 1.07 chip: 5 watts out with 1.2:1 SWR. Does a firmware upgrade require going through the setup/adjustment process in the assembly guide? Thanks for any help on this. 73, Mitch NK3H

开云体育

John,

Hi Joe
How many balloons do you intend to launch at the same time with the same call sign.?
Technically it is possible with the QRP-LABS tracking website, as long as the channel number is different, on each flight, and it would be better if there was no overlap or similar numbers on the telemetry ( 0x4xxx) timing.
That being said, Wsprnet maps probably would be confused and look odd with a number of tx sources and lines coming from the same callsign in different locations all over the world. And in practice ham radio operators do not usually transmit with the same callsign from different locations at the same time.
QRP-Labs tracking is supposed to filter for frequency and the timing of the Wspr and telemetry transmission and so all the balloons with the same callsign, should all be separated in tracking.? Other tracking websites may not filter for all these variables in the same way.
As far as I know, this venture with many balloons with the same unique callsign has not been tested extensively on the QRPLABS tracking website
You might not want to fly the same callsign , launch the balloons, and find there are data collisions. Definitely it would be a good idea to test all your radios on the ground at the same time and see what happens. I personally have 3 callsigns for multiple balloon events. The safest way, and what I would suggest for the moment, is to borrow a callsign from Ham friends and fly different callsigns on each balloon.
There may be another possible way of tracking... Tom W5KUB is showing a number of different flights on Sondehub but there is only one instance W5KUB on the Wspr website.? Perhaps Tom will chime in on this one.
Dave VE3KCL

I think I found the way out.
I went back to FLrig and selected QCH+. It activated. I then went to JS8Call and there is a QCX/QDX radio type.
AND CAT IS GREEN!
Now I need to read the book.
All is well.
J

I have fallen down the rabbit hole. I installed HAMlib and I do indeed see a QCX/QDX radio type,
but to install that radio selection I need to use pphAdmin. To install this utility I need to install a SAMBA server!!
way too much ! I must be in the wrong place.

LostJohn

Thank you, Muhsin. I had wondered what I was missing. This gives me something to look at and consider. Always interested in learning, though I'd be apprehensive about not having the LPF's. I may be more open to that level of adventure if I can aquire more test equipment before I retire in a very few years.?
--
de Stu AI7AN

Is there somewhere I can find the mods, and fixes for rev 3 in one place? or at least a list of them that I can research..
I'll also need same for some rev 1's

thanks
73
Vince
N2AIE

Thx Ron,
Makes sense and is what I expected.? So if bifilar provides a 1:4 impedance step, what would trifilar in the same configuration provide as a impedance step?
73
Timo
zr6tm

Hi Stu
QDX has

4 BPFs in the front end (selection of the toroid here might be tricky, 37-2 or 37-6)

3 LPFs after the PA output

please study the manual for normal and hi-band

you'll figure out

I did some experiment with an LPFless QDX

it is possible...

73 muhsin TA1MHS

?

?

Thx Dave and Paul,
Looking at the snip I agree that the bifilar winding 1 connects the 12v supply to the drain of the mosfet.? Winding 1 then connects to Winding 2 to provide the PA output.? Sorry for this uneducated question, but what function does the transformer perform in this instance.? ??
73
Timo
zr6tm

I'm not having good luck putting all four into a working chain.?
With the QDX USB attached to the Pi I see a serial QDX port with the Config | Setup | Other
tabs. I press the 'init' but I do not see any change in status or display options.
Does anyone know what I am missing? When I bring up JS8Call and select radio flrig flrig I see HAMlib errors.
Much more to learn.
John

Hi Bryan

I had a similar thing happen on a QCX mini, the culprit was a burned up Q5...a BS170...

Strangely this started as a reduction in TX power, Q5, shunting the output to ground partially until it fully burnt out whereupon the TX output returned to normal along with a very signal deprived and deaf RX.

Good luck in tracking it down

73 Steve G4EDG?

Greetings all. I finally ordered my first kit (QDX) from Hans. Something I should have done a couple years ago had I not had a silly confusion about the nature of MFSK in general, Olivia (my favorite mode) in particular. I've been inactive for a decade & ready to start back in.?

Question- Is it reasonably possible to substitute a band or two from the hi band parts kit into a low band kit? Or is there more to it than just swapping out filter parts? Would the software be adaptable by user to reflect the correct band & band limits??

Might not be worth my effort if it requires much engineering know-how. I believe my assembly skills are up for the build, but my radio theory knowledge is admittedly weak. Han's instructions look excellent, just my speed! Looking forward to the process regardless.?
--
de Stu AI7AN