QMX: Selecting RX bands - as it stopped receiving on 20m and 30m bands
Hi Team, I got a QMX that stopped receiving on 30m and 20m bands. It looks not a LPF issue. Could someone elaborate how QMX selects the RX bands with the Band_0 and Band_1 signals? See marked below on the schematics:
What are the combinations for the different bands?
?
73 de Béla
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Re: QMX access to terminal applications
Juan,
You need a terminal emulator program that works with Windows.? I use PuTTy:
Download and install the program following instructions on the site.? Once the program is loaded, you will need to verify which Com Port is connected to the QMX.? I do this using the Windows Device Manager app with a right-click on the Windows Icon.
Open the app and then the Ports folder (this is from my Windows11 Laptop):
Here is the same screen using my Windows10 PC that I connect to my QMX:
The above is before I connect the QMX.? With the QMX connected, I get this:
Note that for me, the new COM port is COM3.
Now open Putty.
Now start Putty.? You should get a screen like this:
Select the Serial button and enter the com port from the Device Manager (COM3 for me).??
Click on the Open button.? A blank window opens:
Press the enter key, and the main menu should open:
The rest is in the operations manual.
73
Evan
AC9TU
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Re: QMX Clicking CW Sound
Hi Gerald,
Recently got my pre-built QMX. Upgraded to ver 14...I'm having the exact same key click issue. Your recording is exactly what I'm hearing. I hope Hans is able to figure this out...it's horrible to listen to on headphones,
73,
D. Altman
KO4YLZ
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QMX access to terminal applications
Hello.
I would like to know how to access to terminal applications using Windows 11?
73, Juan LU9CYV
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Juan,
I should mention that what you described was a bug that has been repaired in the current firmware version 1_00_014.
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Hello, again Juan,
I suggest starting with the operations manual available on the QRP-Labs QMX webpage:
You should upgrade the firmware as instructed in the operations manual.? The upgrade process is described on page 56 of the current operating manual.
Verify operation, and if there is an issue, then try a Factory Reset as described in the Operations manual.
Since you purchased a QRP-Labs built QMx, I would contact QRP-Labs support and request information on how to send them the unit to be repaired if the above can not resolve the issue.
73
Evan
AC9TU
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Hi Juan. When I first completed my QMX, I thought the receiver was dead as I could not seem to get any volume. I found that the volume encoder was defaulted to a setting of 0.25 dB per encoder step. I changed that to 2 dB per step and was able to control volume better and the receiver was working. Hope that helps .. 73 .. Ron
On Tue, Jan 2, 2024 at 12:58?PM Juan < lu9cyv@...> wrote: 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 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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Bela Mucs
Juan
Ronald Taylor
Burt Wizeman
Randy Ott