I just realized that when the QMX starts while on the 20m band (freq 14.070) it has no audio and when changing bands it also has no audio, but when I turn it off while on a band other than 20m and turn it back on , I hear audio although very low and the volume control does not work!!!
The behavior is strange.
I still do not understand anything
73, Juan LU9CYV
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I watched the your YT activating with QMX.? Bravo!
I am still trying to get my QMX Rev1 on the air.? Did you have any debugging to do with your build???
So far I have not been able to get RF out nor receive to do any more than produce steady tones at some frequencies.??
This is my first build of a this type.? It seemed to go fine with the well written/illustrated assembly manual.? However, I did have some soldering issues with the SWR bridge and? fear I have damaged the main board and doing the correction and?perhaps killed the finals testing.
Hope to get QMX going and get out to the parks.
Happy New Year
Charles? K5KXJ
On Tuesday, January 2, 2024 at 06:46:14 AM CST, K9NUD-Steve <k9nud@...> wrote:
I've been catching up on my YouTube videos and just published a September POTA activation using my QMX and a modified PAC-12 antenna. I also used a KN4YB bug, which was a little scratchy at first. Not my best bug work, but the rig performed fantastically with one DX contact on an otherwise difficult propagation day. The QSB was very deep!
If you are learning CW, be sure to toggle the CC button to see the decoded CW.
--
72/73 de Steve, K9NUD
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Hello Evan, how are you? Thanks for answering.
Buy the factory assembled QMX.
My QMX was built for 12V.
I configured all the security measures. Set the SWR protection leaving a maximum of 2. Also set the voltage protection, setting a minimum of 7V and a maximum of 13V. Use an EFHW antenna with a 49:1 ratio.
I powered up my QMX with 11.4V and then made the first QSO at 14.070 with no problems. Then it went to 28.050 and the high SWR protection was activated and the TX was automatically interrupted.
After that the QMX ran out of audio, you can't even hear the band noise.
After all that, I reset the device to factory settings and reset all the security settings (roe and voltage protection).
The QMX turns on and you can see the firmware version.
?
Now I turned it on again and I can hear audio!!!! but it is very low and the volume control does not work.
I don't understand anything
73, Juan LU9CYV
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Re: Stupid screw-up and help to get it fixed.
Jeff Moore,
Have you ever considered writing up your experience or contributing to Hans' troubleshooting guide?
Seems a shame not to share the learnings from the 70 patients you have cured.
73, Mike KK7ER
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Re: QMX SWR meter gone mad (SOLVED)
That is great. My SWR bounces around and sometimes shuts down the xmtr. I am ordering the diodes now. Thanks for the great tip.?
On Tue, Jan 2, 2024 at 1:04?PM Randy Ott < k5hj@...> wrote: I replaced the diodes in the SWR bridge with a matched pair of 1N5711 hot carrier diodes and now I have SWR readings that are essentially 1:1 on all bands.
The supplied rectifier type diodes have way too much reverse capacitance and are unsuitable for RF.?
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Jason,
Thanks for the further details. I ordered the Pi Zero and display yesterday to make a DigiPi and this is the first time I¡¯ve heard of someone using a QMX with a DigiPi. So I¡¯m very excited to know it works and I can build on your work.?
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QMX Rev 2 80-20 Layout Diagram Question
Please pardon the ugliness from the removal of one solder bridge and the attempt to remove another. I bridged the empty, un-soldered pad to C515.? If the Layout Diagram is from the top, I have a problem, if from the bottom, both are ground.? Is the Layout Diagram from top or bottom?? I have since switched to a smaller diameter solder!
?
Thanks?
Burt
K4SRQ
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Corey,
Actually the setup was super easy.? There were some quirks but nothing I thought was a big deal.? Setting it up at home was easy, I'd just made changes on the fly out in the field and wasn't prepared.? Being in the 30s with cold wind stopped me more than anything.? Biggest was going into the shell on my phone and trying to type out a bunch of linux commands with frozen fingers lol.? Commands I had a hard time even remembering.? After that I needed to VNC into it and couldn't remember the password.? Should have had better notes with me (or.. "any notes at all" with me).? My fault, or at least circumstantial.
Knowing what I failed to get working in the field, I'll get it wrapped up in the next few days in the comfort of home and make a post on it, it's a neat little compact and inexpensive cw+digi package.? The browser-based vnc running wsjtx/js8call over a hotspot is really appealing to me.
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Re: QMX SWR meter gone mad (SOLVED)
I replaced the diodes in the SWR bridge with a matched pair of 1N5711 hot carrier diodes and now I have SWR readings that are essentially 1:1 on all bands.
The supplied rectifier type diodes have way too much reverse capacitance and are unsuitable for RF.?
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Jason,
I was looking at setting up a DigiPi with the QMX. Sounds like it¡¯s been a difficult setup. Looking forward to seeing what setup ultimately worked.
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Hello Jeff, thank you for you response. My QMX es Rev 2, firmware 1.00_011 and I bought it builded the factory.
The only instrument I have is a multimeter.
In my first message in this thread, I detail what happened.
73, Juan LU9CYV
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Hi Juan,
Did you build the kit, or did you purchase a prebuilt QMX?? If it is a prebuilt unit, I suggest contacting QRP-Labs to see if they will repair it for you.
What was the voltage the kit was built for???
What was the voltage supplied when operating?
Does the QMX come on, and does the display show the version version number before switching to the frequency display?? If the display does not turn on, the first use of the DMM comes in to verify the current draw when the QMX is turned on.
Do you have any test equipment?? The most important is a digital multimeter (DMM) that can measure DC current.? Without test equipment, the only suggestion that I can make is to find a local Ham club and find someone who can troubleshoot the radio for you.?
There is a troubleshooting page on the QRP-Labs website:
The above is just a start.? There are a lot of possible things that can go wrong.? All are based on how the QMX was operated or constructed.? Please read the manuals (Assembly and Operating) and the Troubleshooting page.? Post back the answers to the above questions.
73
Evan
AC9TU
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Re: QMX in the K1USN Slow Speed CW contest
Thank you, Dick!?
Dosen't work for me, but might be my windows machine.?
HNY!
Simon
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Hello Juan,
there are many possibilities. ?So it¡¯s a difficult question to answer. ?Is this a QMX that you built or built from the factory? ?Is this a Rev 1 or a rev 2 QMX? ?Do you have any test equipment?
jeff
W1NC
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Hello everyone!
Please I need help. I am not undestand nothing of electronics and I want know the reason why my QMX is without audio.
I only turned it on once and I could only make one qso, then there was absolutely no audio.
Please, help me.
73, Juan LU9CYV
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QMX Bugs and Power Supply
Having recently built two QCX-minis I am once again in the building mood.
I hesitate to tackle the build of a QMX as I am seeing a lot of email on the reflector about QMX failures!
My question...have all of the bugs been worked out of the QMXs?
Also I power my QCX-minis from a Bioenno 12V 4.5ah Lithium Iron Phosphate battery which when fully charged puts out 14.46 vdc. Is there a recommended way to drop the voltage from the battery to 12 vdc so I can power a QMX with it?
Ordering a QMX to build hinges on all of the above.
BTW my 20 and 40 meter QCX-minis have never failed me.
73
Jerry WB7S
--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
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Re: QDX Rev 5 High Band Internal Noise
Hey Phil,
Thanks for the idea. My low band QDX does not do that even without any antenna connected and the High Band does so I'm thinking it must be something else.
Recovering from the RSV that's been going around E. Texas. Not fun. Other projects been keeping me off the air much lately. Catch you on the air again soon, Lord willing.
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On Jan 2, 2024, at 08:39, phil - wb4som < mrphilmo@...> wrote:
Hey Cliff,
I had an early problem with this way back when I first got the QDX. In my case it turned out that the BNC connector was not making real good contact on the center pin. A little bit of squeeze solved it.? You doing OK? Haven't seen you on 20m Olivia in a while.
Phil
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Jindra,
At the moment the QMX will not work with fldigi. There is an issue that was created when firmware 007 was released that prevents it from working. Hans is aware of this and hopes to resolve it.
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Hello,
is there a known setup for RTTY using fldigi and VARA setup?
I have had success with JS8Call, although TX signal required unusually high level setting (around -1? to -2 dB, while with TS-590S or G90 it was somewhere in the range -17 dB or lower) - but I suppose the higher the input level the lower the risk of including unwanted noise in the transmitted signal).
However, with VARA and FLdigi I had no TX output. FLdigi uses flrig to control the transceiver (which is perfectly OK), when I switch to TX it seems QMX is switched, too (sound in headphones disappear) but there is no output even when I set transmit level to 0 dB.
Is there anything else I need to pay attention to?
73 Jindra OK4RM
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Check the thread started by Hans-Wilhem on 12-27-2023.
Andrew,
Check the mux bias voltage at the junction of R401, R402 and C406. It should be close to 2.5 volts. If it is significantly different, it is highly likely that IC402 has been damaged while the TX was being tested.
The mux may have fallen victim to a problem with the T/R switch, for which a diode mod has been proposed.
That mod has been discussed in this thread and in a referenced thread. If you need to go that route, install the diode before replacing IC402 and powering up again.
JZ KJ4A?
On Tue, Jan 2, 2024, 7:15?AM M1CJE < andrew@...> wrote: Hi, Looking for troubleshooting suggestions/help please.
I have built the QMX and all is working fine except there is no received signal.? The audio stages appear ok as I can hear my own signal and the volume control works properly.? Tx on 12v is around the 4 watt mark.? The audio filter diagnostic tests show levels around -80 to -100 on all bands. The RF filter and Image sweep tests show similar levels.
The build manual says I should have a connection between pin 7 of IC402 and the L401 windings but this is not there so could this be the problem, but looking at the drawings I can't find the traces and on the schematic it is shown as not connected.? The other connections all test ok.
Any helpful suggestions appreciated.
73, Andrew - M1CJE
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My qmx got out to a park yesterday too.? Made a bunch of cw contacts on 20 all across the us.? A buddy brought along an ATU-10 which worked great with it.? I didn't hear cw clicking that other folks are reporting but I'm also using a very crappy speaker that produces a bunch of undesirable noise so maybe it is but I don't notice. Bigger problem for me is it regularly added extra dits (or was it dahs, don't remember) and I'd have to make a bunch of corrections. It was aggravating but not so much I didn't want to keep at it, still a fun easy to use rig.?
I also hooked it up to a pi zero 2 running digipi.? Was unsuccessful getting ft8 contacts in the logs, but for digipi reasons unrelated to the qmx. One thing I found odd was the audio setup was much different than what I was expecting, audio device names didn't match what was in the manual. I played with it and found a combination that worked but audio out was tricky. Not by it now to get a screenshot but maybe will soon.?
73, Jason KO4NDP?
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Juan
Burt Wizeman
Randy Ott