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Buy that man a coffee!
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Actually, that might be a neat idea.
We've been waiting for 9 long months for it while for Hans it's been 9 months of work for us, to have even more fun with this little rig.
Here's the thing - why don't we do a "coffee flood" for Hans? Each of us, who upgrades his qmx with ssb feature, buys coffee (or two, up to you) from the link in Hans's footer. Let us demonstrate our appreciation.
What do you guys say?
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Re: Observing CW sidebands?
As fate would have it, yesterday I received a book I ordered. It is a collection of articles written over the years by Andy Talbot, G4JNT, in the Design Notes section of the RSGB's RadCom magazine. The book is called "Design Ideas for Radio Amateurs". I was skimming through it this morning ... randomly jumping from page to page.
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In August 2015 Andy wrote an article titled 'A cautionary tale about wideband glitches from the Si5351 chip and others'. The second part of this article talks about potential challenges related to VCO presets, recalculating the VCO presetsing, and calibration which can be a 'headache' if the synthesizer is used in an 'agile' application like generating multi frequency modulation (WSJT modes or WSPR) or in frequency hopping. He mentions challenges related to the chip recalculating the VCO presets, recalibration, and that this is associated with interference. Apparently "the loop will be unlocked and the VCO free running for a few cycles of the comparison frequency, typically a few microseconds". Andy also makes a brief comparison between the LMX2541 and the Si5351 - the latter not being 'so fortunate' in the sense that the issue is more difficult to address.
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The article is too technical for me, I have to be honest, but it seems to suggest a possible limitation of the chip (like Hans suggested, when he said "spur inherent in the RF synthesis process in the '5351 Synth chip"). Jerry also reffered to the VCO in his previous reply.
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73,
Bogdan M0OOV
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Great to hear that. It's very exciting to be a part of the QMX story. QMX was my first self-built transceiver.? I am looking forward to a new adventure with QRP SSB on QMX.
I would like to propose to the entire QMX/QMX+ community to celebrate the introduction of SSB with a QMX party. Let's meet together on the bands in one weekend after the firmware release and call "CQ QMX".
Karol
SP1PT
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The SSB microphone input uses the iambic paddle input, the tip is PTT and the ring microphone with the sleeve ground for both.? The microphone line has phantom power and looks as if it will work with an electret microphone.? It's pretty easy to make an adaptor cable to a PTT switch and a microphone, the sort of thing Heil produces for it's headset.
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The recent 'SSB is almost here' thread says that initially microphone inputs will be using the USB sound card or the external microphone input. I guess that a PC transceiver control app will have the ability to route the PC microphone input to the QMX USB output and use the CAT control for PTT.
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Chris, G5CTH
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Good idea. He deserves all the encouragement.
Here's the thing - why don't we do a "coffee flood" for Hans? Each of us, who upgrades his qmx with ssb feature, buys coffee (or two, up to you) from the link in Hans's footer. Let us demonstrate our appreciation.
What do you guys say?
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So my suggestion - if the hordes find this agreeable
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It's been long so far, even 2 or 3 weeks don't make big change. Just do what makes you feel more comfortable with the release.?
:)
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Buy that man a coffee!
?
?
Actually, that might be a neat idea.
We've been waiting for 9 long months for it while for Hans it's been 9 months of work for us, to have even more fun with this little rig.
Here's the thing - why don't we do a "coffee flood" for Hans? Each of us, who upgrades his qmx with ssb feature, buys coffee (or two, up to you) from the link in Hans's footer. Let us demonstrate our appreciation.
What do you guys say?
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Re: QMX+ PuTTy sweeps: YIKES!
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Re: QMX+ PuTTy sweeps: YIKES!
Did you remember to install the jumper to the BNC?
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I presume USB means Upper Side Band in this case, not Universal Serial Bus.
15 Mar 2025 Cmt 06:52 tarihinde Paul - AI7JR via <paul.hanchett= gmail.com@groups.io> ?unu yazd?:
You should find that there's a QMX input and output device you can select. Can't advise you as to what the specific settings should be, though... :-(
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Paul -- AI7JR
On Mar 14, 2025, 20:26 -0700, George Korper via <georgekorper= gmail.com@groups.io>, wrote:
Hi All,
If SSB is coming with USB audio how do you connect a USB mic to it? Windows???
Is there a simple way to do this? Na3p ?
73,
George?
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You should find that there's a QMX input and output device you can select. Can't advise you as to what the specific settings should be, though... :-(
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Paul -- AI7JR
On Mar 14, 2025, 20:26 -0700, George Korper via groups.io <georgekorper@...>, wrote:
Hi All,
If SSB is coming with USB audio how do you connect a USB mic to it? Windows???
Is there a simple way to do this? Na3p ?
73,
George?
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Re: QMX+ was working FB now bricked
Disconnect from power and check resistance to ground of 5V and 3.3V. Should be a couple of K or more for both of them. Should give you an idea of where to start, anyway.
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Good Luck!
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Paul -- AI7JR
On Mar 14, 2025, 18:50 -0700, glen.brown10 via groups.io <210glen@...>, wrote:
Worked great for a couple of months.? Many QSOs, CW and dig.? Then it stopped working. No display.
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Vin=12.1v
V+=12.1 only while pwr nob pressed
Vcc=0 or 3 mv momentarily while pwr pressed
Vdd=0 or 20 mv while pwr pressed
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I replaced the 5.6v zener.? No joy.
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Suggestions?
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TNX Glen W6GJB
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Hi All,
If SSB is coming with USB audio how do you connect a USB mic to it? Windows???
Is there a simple way to do this? Na3p ?
73,
George?
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QMX+ was working FB now bricked
Worked great for a couple of months.? Many QSOs, CW and dig.? Then it stopped working. No display.
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Vin=12.1v
V+=12.1 only while pwr nob pressed
Vcc=0 or 3 mv momentarily while pwr pressed
Vdd=0 or 20 mv while pwr pressed
?
I replaced the 5.6v zener.? No joy.
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Suggestions?
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TNX Glen W6GJB
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On Fri, Mar 14, 2025 at 05:07 PM, Zhenxing Han N6HAN wrote:
if we use a potentiometer, we can effectively make QMX’s output power adjustable
I'm not so sure about that.
The QMX does not like the supply voltage changing while it's running.
Mine rebooted when I tried it.
And the Rev 1 models would blow up (before Hans swapped the tantalums for ones with higher voltage rating).
The SMPS have to track the changing input voltage and adapt quickly to produce steady supply voltages for the microcontroller, etc.
There is a long thread on this topic from the QMX rev 1 era.
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73, Mike KK7ER
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Thanks for all the incredible things you have done. Spend time with your family, rest, forget about everything for a while. Fed Ex found my new address. Thank you for your help getting the QCX mini here. The UPS driver laughed when he saw my signs telling FED EX where to turn. 73s John N4HNO
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So instead of using fixed R3/R4, if we use a potentiometer, we can effectively make QMX’s output power adjustable, right? Maybe not very accurate in terms of the absolute output power, but should be pretty accurate in terms of percentage. Like defining 12V to be 100%, then at 12V x 0.7=8.48V would be 50%, something like that.?
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Congratulations Hans!
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Your release scheme seem fine but make sure you take any off time you need before it escapes because there will probably be a flood of feedback and even if it doesn't lead to changes being needed will need attention.
I wouldn't worry about alpha, beta, etc., they are fine if you have a development team, a test department, project managers etc., but for a one man team aren't appropriate.
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I've already got an adaptor cable made for a Heil Electret microphone and a PTT switch...
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Chris, G5CTH
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Don, thanks for posting!
Since your jpg will disappear in a few days, I have given it a permanent home at:
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Looks like a very good solution to the problem of limiting voltage to the QMX at 12v.
I believe that circuit will have a quiescent current of around 1ma.
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Could change the resistor divider to give 9v out, for example? ?R3=40k and R4=50k,
or any resistors of the same 4/5 ratio.
Given that the LM2950-5 is a 5v reference, we need that ratio to give
? ? ?9v*50k/(40k+50k) = 5v on the base of Q2.
If the 9v output exceeds that value, the base of Q2 rises above the base of Q1?
and raises the voltage at both emitters, resulting in no current through Q1
and a rise in voltage at the Q3 gate.
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Q1, Q2 could be any small NPN's, such as a 2n3904 or the QMX's BC817.
Q3 is an enhancement mode PFET, it must be able to dissipate any excess voltage?
at the expected current.? For example, with 17v in, 12v out, and a 2a current,?
it will be dissipating (16-12)*2 = 8 Watts.
May need to be bolted to the back cover to dissipate the heat.
The LP2950-5 is a 5v voltage reference, could be replaced by a 5v zener and a 10k series resistor
at slightly increased quiescent current and somewhat poorer regulation.
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Perhaps we could have a PC board with pads for all the parts.
Gets mounted to the back panel by the tab of Q3.
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I doubt many of us have signed up for SPRAT, perhaps we should.
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Jerry, KE7ER
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On Fri, Mar 14, 2025 at 02:09 PM, Don, ND6T wrote:
Another option is a Very Low Drop Out regulator like G4COL described in the latest SPRAT (issue 201) page 12. More efficient than a buck regulator, all analog, and capable of huge currents.
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On Fri, Mar 14, 2025 at 07:51 AM, Hans Summers wrote:
So it's worth it. But I should give birth now.
Breathe!? Breathe!? Push!? Push!
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73, Mike KK7ER
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Karl
Paul - AI7JR