On 05/05/2025 16:56, dg7dk via groups.io wrote: As soon as it goes to TX in the 20m band, the LED flashes twice in quick succession. The QDX is then blocked Andree, Does it do this if you use a dummy load? 73 Alan G4ZFQ
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Re: Feature Request List?
"Thanks again.? I didn't know that you could clear the SWR error by entering/exiting the menu.? That's sure easier than power cycling!"
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I agree with this, but on my QMX Ver 1 and 4, Software 027, I find the SWR exhibits crazy instability during the 'hardware test' after clearing the 'S' with the menu entry/exit.? The 'tenths' digit is unstable and the 'ones' digit is illegible.? Powering down solves the issue.
I agree that just don't transmit would be a great solution. It may be that the dreaded 'S' situation is created by a safety system that is much faster than something that would abort transmit during dangerous SWR.??
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Thanks for the system, Hans.. I am sure it has saved my QMX stable more than once.? I use hardware test to tune my little Z-Match tuner when I change bands, running at 30% .
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73
Dick
W4PID
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On Mon, May 5, 2025 at 06:59 PM, <dg7dk@...> wrote:
the LED flashes twice
From the manual (RTFM)
"2 flashes:
QDX is receiving audio from your PC. But the volume is insufficient to trigger the key-down
(transmit) action."
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73 Ludwig
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Hi everyone,
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A quick little question: After receiving my fully assembled QDX, I noticed that it is not working correctly in the 20m band. As soon as it goes to TX in the 20m band, the LED flashes twice in quick succession. The QDX is then blocked and I cannot access it with wsjt-x (reports CAT error) or via a terminal program. Only after disconnecting the power supply and plugging it back in again is access possible.
The error does not occur on 40m. Everything works fine there.
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I have tried the following:
1. Laptop with Windows 10
2. Laptop with Windows 11
3. Various USB cables
4. Older Firmware Versions
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Unfortunately, everything was unsuccessful.
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I hope someone in this group has an idea of what I can do and look forward to your feedback.
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vy 73 de Andree, DG7DK
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I have used 26 AWG wire successfully. If it fits, it will work well.??
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I use that as fast reference.
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--
Allison
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Post online only,?
direct email will go to a bit bucket.
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I usually go to the VK3CPU toroid calculator to see how many turns will comfortably fit on a given toroid. If you have a Windows machine, mini Ring Core Calculator is great
.rr
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Thank you, I tested wrapping with the #26 and I was able to get 18 turns on the toroid until the wire started overlapping in the middle. I am going to get some #28 and finish the puzzle today.
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73, John W7OTD
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Yes, I meant 3 wires on the trifilar toroid. I twisted it 60 turns, while connected to a drill, with moderate tension to keep it straight. When measuring for shorts in-circuit, all the 6 wires appear to be shorted, but this is probably at least partially because it's still in-circuit...? I'll be taking it out today and checking for resistances again, just to make sure.?
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#u4b Deniyap-1 and Deniyap-2 flights
#u4b
Hi all
Yesterday we had a total of 7 visitors to QRP Labs from Mugla Deniyap (technology workshop) and Mugla university. Only one (Necati TA7MNA) is a radio amateur. We had a great time with hours of discussion about QRP Labs products and amateur radio in general. Then we arranged a workshop activity to prepare and launch two U4B tracker balloons, which we have called Deniyap-1 and Deniyap-2; these fly with callsigns G0UPL and TA7MNA respectively. By the time we were ready, and had driven to put helium in the balloons, it was evening and already completely dark. We launched from a nearby football field by the light of car headlamps and mobile phones.?
Of course as it was dark we had no telemetry from the balloons and no idea of success or failure until the following morning. But surprisingly both Deniyap-1 and Deniyap-2 showed up near Suez, Egypt?having crossed the Mediterranean overnight. Deniyap-1 (callsign G0UPL) suffers a broken antenna (the wire snapped during launch) so far fewer reception reports. Deniyap-2 has crossed the Northern part of Saudi Arabia today and is almost at the Iraqi border.?
I prepared a web page which includes lots of photos of our activities, construction and launch:?
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Well I was supposed to be fixing the charging circuit on the bike this morning but switched the QMX on and then started playing with the code.
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Starting to add analogue dials ( not converted from dB to S-unit yet ) and just dove down a few software rabbit holes :-)
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Gitgub repository is live but some cleanup to do before I post the link :-)
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73 Simon G0FOZ
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Hi,
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My results are similar and it is so simple to use PTT ( a CW straight key for instance in the mike jack) that I have put the pursuit of vox on hold until Hans resolves it in firmware.....mainly because it seems to be involved with the issue of two microphones and how they work together.?
Until all this is sorted, which may take awhile,?
I have decided to 'chill ' .??
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73,
George?
K3GK
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Re: QMX+ Low Power After SSB Update
This appears to have happened to my QMX+ too, but by 80-20 QMX was just fine after the SSB update?
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Unfortunately I've not been able to get the 80m phase calibration past about 1500. It always ends with a steep line and a message saying more than 30 degrees change.? The USB and LSB calibrations also look weird, just a straight horizontal line.
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More successful on other bands although 30m has some straight lines also but at least the phase calibration finishes.
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73
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Simon
VK3ELH
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Re: Microphone output in SSB
Yannig,
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You are correct and I miss spoke my order of equipment, the wattmeter is between the radio and tuner.
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John Dunn?
KJ4WSR?
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Re: Heavy ssb tx distortion
Try piping in some very low level/much attenuated ?audio from a broadcast talk radio channel earpiece socket to check if it¡¯s the radio or microphone?
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Re: QMX/QMX+ Frequency alignment
Good to know about the ESC button ! Not straight to ctrl Q.
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Re: QMX+ Final failure on 12m
Hi the only suggestion I can make is to sweep the out put transformer with a VNA, see if there is a kink in the response st 12m.
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The PA is not a linear stage, so difficult to sweep with the FEts in place.
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You will needt o match the input to 50 ohms.
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Failing that just wind a new transformer. Can swep the 12 LPF for flatness.
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There must be some loss somewhere. Maybe the fix eill just be substation!
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KR
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Andrew
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Re: QMX+ Low Power After SSB Update
It seems that some QMXs are OK and others not.? I get the impression that a QMX that is bad will consistently have problems and it would be nice to find out why.
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My theory is that when a QMX starts to run at half power one bank of QMXs has failed and the other not.? Half the drive gives half the power.? It would help if someone could check this and ideally say which bank, the upper or lower.
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A Component tester would be best, mine reports a goodish BS170 as a N-E-MOS Vt 2.57V, Cg 64pF, Rds 7.6 Ohm Diode V 711mV.
Measuring the resistance on each removed FET might give a clue, measure both ways - S to D and D to S.? I see infinity one way and 0.6 Mohm the other way.? If it's the same both ways it's failed.? (This isn't an infallible test, all it's doing is checking the parasitic diode.)
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Chris
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If you think that one part is wrong then look for tests that don't involve it.? For example the hardware diagnostics Tx test doesn't use the trifilar transformer because it is only in the Rx path.? Set a low voltage and low current limit (7V, 500mA) and try Tx.? You should see Tx power and? a low SWR.? And check the peak voltage across your dummy load, this should show roughly the same power as the QMX+ reports.
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If there is no Tx power on any band check L502 and T501 for bad soldering.
If Tx power is indicated by the peak voltage across your dummy load but not shown in the QMX diagnostics check the soldering of T507.
If some bands give power but not others check the soldering for the toroids in the LPF used by the bands that don't work.
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As for the trifilar toroid the only time it's practical to test for shorts is when it's not installed.? Your best option is to unsolder it and check that there are no shorts.
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It's probably simpler to start with getting the Tx to work because the signal levels are higher so more easily detected.? Once Tx is working the simplest Rx test is to connect an antenna and listen.? You should be able to hear FT8 on 20m almost any time, maybe use your PC to decode it.
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HTH
Chris
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Richard Hattaway
va3rr
John Mount, W7OTD
Si Smith
Bruce Akhurst
Andrew Lenton