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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: STM32 dead
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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Re: QMX receive partially works on FT8
#QMXplus
I concur with Jeff's earlier comment that this sounds like a PCM1804 chip failure mode.? It is about the only thing in QMX that will create high-level digital noise that completely covers up strong received signals.? I had one that did the opposite-it was very high noise when first turned on for 30sec or so, then fine as it warmed up.
Stan KC7XE? |
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Re: QMX+ Inside a Tent For POTA and SOTA
Consider something like a wolf river coil vertical just outside the tent.?
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There is a parameter called radiation resistance. For a very short antenna it can be just a few ohms, overwhelmed by losses. Not that I didn't reach P29CC on 10m ssb from a 3 foot whip from eastern US once. But these are pretty rare.?
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Curt
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Re: QMX receive partially works on FT8
#QMXplus
开云体育I turned on my QMX without the USB cable with a dummy load. The sound was nice and quiet for more than 45 seconds but then the noise came on quite loud. I then connected it to my antenna (20m). Turned the QMX off and then on. Heard ft8 signals for almost a minute but noise came on loud enough to require turning down the volume (no ft8 signals anymore).?Ron H K7DQ? On Jan 12, 2025, at 1:03?AM, Chris via groups.io <chris.rowland@...> wrote:
? Your Tx sweeps look OK but your Rx sweeps show no Rx, nothing but noise.
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I'd check the inductors and transformers used by the Rx, the BPF and the trifilar transformer. Bad connections here could be the problem.
Another thing to try is to turn it on with no USB cable connected and listen to the FT8 signal.? Does it stop after 45 seconds?? If it doesn't that may be an indication that something is wrong in the USB cable region, although it's difficult to say RFI if you aren't transmitting.
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All speculation but may help,
Chris, G5CTH.
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Re: QMX+ Inside a Tent For POTA and SOTA
George,
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No reason at all why a QMX should not work inside a tent.? How big is your tent? Are you talking about a camping tent, or something like a pavilion or picnic table shelter?? Most camping tent don't even have enough room to stand up in.
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Your antenna will be limited by the height of your tent. As you know the most important part of your station is the antenna. No doubt you can get something to work inside your tent, but I think you'd be better served with an outside antenna.
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I do a lot of POTA.? My two go to antennas are an EFHW and a QRP Guys tri-band vertical. The vertical is held up by a 5.6 meter telescopic "squid" fishing pole. I have multiple tuned wires for the EFHW, although the 40 m wire will acceptably handle 40, 20, and 15 meters without needing a tuner. The tri-band vertical is also a resonant antenna and it covers 40, 30, and 20--but with switching out a few more tuned wires, it will handle 17, 15, 12, and 10 as well.
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Which antenna I set up depends on the activation location. I do a lot of POTA activations at Cape Lookout National Seashore--no trees on the seashore--so I use the vertical held in a sand spike.? I activate another location where the ground is too rocky to put in a ground spike. That's where I need to use the EFHW and a throw line to hang it in a tree.
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My activations are all CW QRP at 5 watts, but I don't feel handicapped. About 5% of my QSOs at Cape Lookout are DX. I've worked the British Isles, Europe, VK land, Argentina, the Caribbean, Chile, Alaska, Hawaii and more, on 20 meters.
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Some 95% of POTA operators are Hunters. Only about 5% are activators. With a 19 times more Hunters than Activators, and spotting on POTA.app, you will seldom have difficulty getting at least 10 QSOs for an activation.? The hunters will nearly always have a better antenna and be using more power than you are. They'll assume that if they can hear you, they can work you. And they're right! My sent RSTs run 2 or 3 S-Units higher than what I get back with my 5 watts, but we still make contacts, and lots of them.? But that's no reason to use a compromised antenna if you don't need to.
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For the record, I think both the EFHW and the tri-band vertical work equally well. I haven't noticed any advantage with either one. Again, which one I use depends upon local conditions. I make my own 49:1 transformers, and since I only use QRP, they can be small and light. For that reason, when I traveled to England and Ireland last September, I took the 30 and 40 meter EFHW antennas, my low band QMX, my 20m QCX, and the rest. Even though the telescopic fish pole collapses to 22", and weighs about 10 ounces, I didn't take the tri-band vertical.
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My time was limited, as my family was waiting for me. I ended up with 10 QSOs over 3 attempts, all on 20m. Even though I spotted myself on POTA.app, I don't know how much the Europeans check POTA Spots.? My early afternoon operating times translated to 7-9pm on the east coast, where they could have noticed my spots. And finally, I think most of the European CW activity was on a lower segment of the band than where I was used to calling CQ? POTA.?? Too bad that didn't occur to me at the time.
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All the best, and good luck.? Feel free to PM me if I can be of help to you with further questions.
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Jack N8EU
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Re: Your QMX output experiences @12volts...?..and by the way, what an amazing radio.
Thank you for your input Stan,
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I looked at the info in QRPLabs web site and I see that the QMX series have the same final transistors as my QCXs and the PFR-3. My experience is those are robust parts. In have not looked to who is running classic, D, or E. That might make a difference but it clearly states those transistors in the QMX do not even need a hearsink.
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It is possible to destroy some pretty rugged vacuum tubes leaning on them too hard. some of the same cautions apply. Meanwhile My ham hobby has been morphing into the 21st century. My sealed lead-acid 12 volt batteries get up a bit over 13 volts at full charge and the new LiFePO4 batteries get closer to 14 volts with the present charger. I have all of my "12 volt" stuff using the Anderson Power Poles and all the 5 volt stuff using USB cables & connectors. I have two different kinds of power sources and I would like to not clutter the local environment or picnic table with several more. It would be trivial to acquire an 11 volt supply, a 9 volt supply, and on and on then inventory several different connector types to avoid disasters. Too much stuff to carry to the park or to Field Day. Also clutters the desktop.
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So now I have mentioned some of my reasons for asking my questions. If I get more responses like the two I have now I will move the QMX up on my list. I do not require every last milliwatt so all I need is the means to reduce power for rtty and other high duty cycle modes. Meanwhile..I can operate one of those on CW as it comes off the bench. I started with two watts on CW and SSB and worked a lot of QSOS with modest antennas.All those bands in one small box!
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73,
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Bill ?KU8H |
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Hi Stan, thanks
1) I typically use 600 Hz filter in CW mode in the Na3P display - that has always been fine. ?In Digital Mode the QMX+ turns off the cw filters as far as I know. ?Mute is not on..;-)
2) Yes the spectral display in Na3P is 100% fine - so I/Q data is fine. ?BUT... not sure how the digital audio gets extracted from the I/Q inside the Na3P software.. I am assuming the Na3P software demods it like it does for USB etc
3) yes antenna is fine... work CW stations all ?day long with the QMX+
4) yes Na3P and WSJTx can control the frequency of the QMX+ so cat control is fine.
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So while I agree it sound like an issue in Windows... .I tried WSTJTx on my MacBook Air and got the same exact results... extremely low level of "audio" input.
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All other audio sources ?eg: YouTube etc play perfectly fine on the Windows laptop.
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I have another thread started with this so I should let this one die on the vine so to speak...but thanks
Mark
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Re: QMX+ Inside a Tent For POTA and SOTA
Hi Russell,
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With the short, loaded vertical (that could fit indoors), the symptoms of RF in the shack/tent/hotel-room were that the QMX SWR protection trips, it stops transmitting, the QMX resets itself, USB connection drops, etc.? Also, it was harder to get a match to the shortened vertical using the ZM-2 tuner without an RF choke at the antenna.? The mode doesn't matter so much but if you are "on the edge" (meaning level of RF on the coax shield is marginally bad), then low duty cycle modes may go longer without trouble than high duty cycle modes.? YMMV...
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73, Mike KK7ER
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Lots of possibilities.
Stan
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Re: QMX+ - digital audio output suddenly went away
This is more likely a problem with windows connection with NaP3 or the USB cable (more things to break on this side of the interface).
Does Windows still see the device?? (Open Sound Settings -> Sound Control Panel -> Recording tab: it should be in this list)
Does NaP3 still see the device, and in run mode?
If you turn I/Q mode off on QMX+, is there change in the NaP3 display?? ( the spectral display should change to just show the two adjacent energy humps of the left and right audio channels, at a different center offset)
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Did you try to restart the QMX+?
From QMX+ perspective, all of the 'missing' functionality is software (firmware), so restarting the unit should fix it if the problem is on the QMX+ side.
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QMX+ - digital audio output suddenly went away
What I mean is this: ?I use WSJTx and NaP3 (sdr app) and it all worked flawlessly until today.. suddenly there is no audio showing up in WSJTx and no audio that I can hear from output of NaP3 ?BUT ?I/Q is enabled and works totally fine... so...I must have done something to make the "digital audio" interface go away?? ?
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I can hear all audio out the front panel jack just fine....
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Very weird...any clues ?
thanks!
Mark |
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Re: QMX & QMX + Output temps?? Hans?
Richard, I don't have any specific temperatures to recommend. Junction temperatures for the BS170s will certainly be higher than case temperatures. Probably much higher. 150 C is probably the highest temperature that the junction can stand, possibly less than that. The case temperature is going to be much lower than the junction temperature. How much?.?.??
My IR temp meter has a laser pointer, but the correlation with temperature pointing is not consistent. I just move the pointer around to get the highest temperature no matter where it is.?
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73, Dan? NM3A |
Peter HB9EBE
Howard Lamhut
va3rr
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