A number of times I've had the situation in digital mode where the QMX is not transmitting as expected. I immediately get concerned that something is blown. The last time this happened I connected a dummy load and went to the diagnostic screen in terminal mode and still no transmit. Only then did I think, oh, maybe transmit lockout. Sure enough, cycle the power and its back working again. I wish there was some indication on the screen for transmit lockout. I've blown so many finals in the QCX and QDX that my first thought is always something has failed.?
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Re: question 50 watts amp
hanz YL3JD via groups.io <yl3jd@...> wrote: the ps for the amp us homebrew? I used a Dell laptop PSU. 19.5 V, 6.7 A.
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Re: QMX+ Toroids - To Glue or Not To Glue?
Rubbing alcohol will release hot glue. BUT on a torroid with wire wrapped around it, it will be more difficult. I don't think its hot enough to damage the coatings though.If you use it do so in moderation and try not to get it in the hole as its much harder to get it out than just a dab on the bottom side.
I have used a couple tiny drops of fingernail polish on my touchy band pass filters to help hold windings in place. Its strong enough to hold winding still if you brush it with your hand, but can easily be snapped loose if an adjustment is needed later for some reason. Again Dont drench it.
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In fact, just last week I was trouble shooting a problem with my qcx+. L1 had been inadvertantly bumped around so much that one leg did break off, so your concern is somewhat valid if you are not careful. Fortunately It was solderd to the top side and repair was easy. (HINT HINT)
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regards,
Bryan, N0LUF
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f6ehj via groups.io <f6ehj@...> wrote: I deduced that only the STM32 remained. I put it down and the short
disappeared. I ordered one from Farnell. the QMX and QMX+ (I assume we're talking about QMX), and it's guarded by him (not distributed as a file to be loaded). This bootloader is then used to load the firmware downloaded from the website, and the firmware itself is encrypted in some way (so only this bootloader can decrypt and flash it). This ensures that the firmware can be loaded only onto boards bought from Hans (makes it more difficult to make and sell clones). If that's the case, then you won't be able to use the STM32 you ordered...
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
Stan Dye via groups.io <standye@...> wrote: I do not believe QMX finals are nearly as fragile as they are reputed to
be.? I have not blown any in my QMX+ nor the two QMXs that I own.? And
if you are only operating CW, 12.0V is a good guideline, but operating a
few tenths or more above that will likely not ever cause problems, if
you operate into a reasonably well-matched antenna system (which I
postulate is a 2:1 SWR or less). I blown finals in my QDX by driving a poorly matched load (including when the BNC connector made a poor contact). QMX has a protection against large SWR. And yes, if QMX had an output drive/power control, you could eliminate
most of the risk of failure in the finals by turning down the drive.? I
hope such a feature will be added to the firmware. There's hardware for that, so it should be easy to do in firmware... On the other hand, you can just lower the supply voltage.
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
Stan Dye via groups.io <standye@...> wrote: I'm not going to bother with that.? The QMX is supposed to be QRP, and
for highly-portable use.? I have a fine 100W transceiver if I want more
power at home. The problem, as always, is money vs time. For a long time I didn't want to spend money on a proper, factory-made, 100 W transceiver, especially as I'm mostly interested in CW, so a transceiver doing SSB would be an overkill. I'm still weighing pros and cons (DIY vs something that just works, plug and play, and is on warranty in case it doesn't). On the other hand, QMX isn't too complicated for me to diagnose and fix. It's a simple and elegant circuit. A factory-made rig, once warranty runs out, probably would be. My concern is with the receiver. How does the QMX receiver compare to the one in, say, Yaesu FT-891 (a rig I want to buy)?
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
Scott VY1CO via groups.io <scott.vy1co@...> wrote: In fact I am wondering if I can make something of my QLabs 50w amp and a
series of relays to switch out the low pass filters... Definitely. I'd use LPF selector signals from QMX to switch bands.
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Re: QMX, one of op-amps self-oscillates at 25 MHz (or picks up the system clock?)
Tony Scaminaci via groups.io <tonyscam@...> wrote: Design reviews were standard practice in every company and US government
facility I worked at. I both dreaded them (redesign, ugh!) and
appreciated them (learned a lot). I see. Seems it's the same as peer reviews in software development, but we also use some automated tools to highlight common problems (in my current company it's SonarQube and clang-tidy).
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I finally finished, more or less, my shack clock. I decided on the Steam Punk theme to match my 40 meter QCX. I'm still working on the programming for the readout, and I need to install external programming buttons. I'm not sure if I should put the buttons on the front with a couple of meshing gears on them, or just hide them on the back.??
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73, Dan - W2DLC
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Re: QMX+ Toroids - To Glue or Not To Glue?
While they are positioned differently in the QMX, I did see suggestions for glue.? Haven't used glue and have no adverse effects.? If you watch a video of Hans adjusting a QCX, you can see toroids being pushed every which way and he doesn't seem concerned.
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Good luck with your build. These are AMAZING little radios!
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72 de N4REE, Bob Easton - QRP CW forever
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Re: Initializing:Enable SI5351A
Hi,
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Q503 and Q505 BS170 MOSFETs seem to be faulty. When I removed them, my device worked. I ordered new ones, I will install them and check again when they arrive.
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Thank you.
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
That’s what the “tune” menu does. With a selectable percentage. ? When I use a match with my qmx it’s a BLT + that I built which has a dummy load in line with the antenna, so that cuts the mismatch down to 2:1 max. Then, I go into the tune menu at the frequency I’d like to operate and it puts out 25% power into the tuner/antenna. I fiddle for the dip and we’re off! ?I’ve not had any final issues with any of my qrplabs kits. But I believe the function you’re looking for already exists unless I don’t understand the ask, which my wife will tell you is a possibility ?.?
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Hello list,
maybe I didn't see it, but is there a option within the terminal menu to reboot the QMX+? Ir is there none available?
Thanks in advance, and have a nice day!
Cheers,
Torsten
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vy 73 de Torsten | DB2TE
/"\ ASCII Ribbon Campaign
\ / Against HTML Mail
?X www.asciiribbon.org
/ \
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The answer was hiding in plain sight, I had the 'No own call decodes' box ticked, I looked for it under settings only.?
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Thanks,
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Lucien
GW4SYI
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Re: USBC connector not installed correctly on QMX+
Mine came like that, too.? The surface mount soldering happens on the top of the board for those pins, so often it will not fill through to the bottom. Also note that all QMX+ r2 go through firmware loading and sone level of test at the factory, so the USB port was functional to do that.
So it will likely work fine.? I wouldn't worry unless it starts giving you problems?
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Re: USBC connector not installed correctly on QMX+
Adam, check this thread:
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/g/QRPLabs/message/135222?p=%2C%2C%2C20%2C0%2C0%2C0%3A%3ACreated%2C%2CQmx+usb+connector%2C20%2C2%2C0%2C110054301
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Peter HB9EBE
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On Sun, Jan 12, 2025 at 10:10 AM, <f6ehj@...> wrote:
diode was removed, the short circuit was still present.
I had the same symptom on my build of the QMX+. ?
It was during initial testing after build.
I was operating the unit from my bench power supply in a current liming mode.
I think it was set to 200ma max, (whatever the manual recommended).
Everything seem to be working fine and then it went dead.
I noticed the current was at max, where it was operating around 80mA.
I quickly powered it off and noticed one of the power supply board was hot. (don't remember which one)
I inspected the board for a solder ball rolling around but could not find anything.
Turned the unit back on and it powered-up fine.
In further testing I found the receiver was deaf. : (
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(I ended up sending it to a gentleman that Hans recommended and he replaced the A/D)
When he received it however, he said it would not power on.
His inspection found a solder ball under the CPU, (between the actual chip and the solder pins).
He said it was fun getting the solder ball out.
Might check for that.
Good Luck!
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Albert
KE0PRX
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USBC connector not installed correctly on QMX+
Just received my QMX+ Rev 2 and started putting it together. However, under further inspection, I am a bit concerned about how the USB-C connector does not appear to be fully soldered on. I would expect that the holes and pins on the pads (circled below) should be covered by solder, but in fact this is not the case.
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Should I be concerned? If this is something I have to fix, can anyone reccommend the soldering settings I should use if they differ from the rest of the board?
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Thank you!
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73,
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W7OKE
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QCX classic 40METER key click
I have the QCX classic 40 m PC board revision 3… I have seen some topics on this issue but it was on the revision 5 version which has different capacitors than the revision 3 board.
I may be thinking of selling this in the future but I thought it would be interesting to see if I can eliminate the key clicks before I sell it.
thank you everyone.
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
A relatively easy way to deal with the QMX power in your situation is to get one of the inexpensive buck-boost power modules (the 3amp ones are very small), set its output for 12V (or your desired setting), and build it into your powerpole to QMX cable adapter.? ?These work quite well for qrp voltage regulation, and work with your supply voltages.
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Daniel Conklin
N4REE - Bob
Peter HB9EBE
Howard Lamhut