Re: #qmx+ #qmx #qdx Documentation updates
#qmx
#qdx
Thank you for the update Hans, my mid band kit has the black cores, I just need to finish another project and then I’ll get started with it.
I noticed that you also tided up the formatting in a couple of places, where the images were obscuring the text.
In the latest QMX manual, the instructions for T507 still refer to using 0.6mm wire for the links.
73 and Happy New Year, Nick G0OQK.
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Re: AB8DF CW Practice / Rag Chew 1/2/25
On Thu, Jan 2, 2025 at 01:50 PM, Ed Kwik wrote:
might try 20 meters if I can figure out a good time of day for it. Like the idea of operating where Techs have CW privileges and tempting them to get into CW
Techs have CW privilege on 15m.? ? 21.0675 is supposedly a "Slow CW" calling frequency (forgot what group was designating that..).?
?
When I couldn't hear you yesterday, I answered a slow 15m CQ and then got in trouble because I have my key speed set to 12wpm.? The fellow (in Pennsylvania) came back to me at 15wpm.? I managed to copy my call and GM, then gave him a signal report but couldn't copy my report or anything until I heard FB..TU..73 WB0ZJJ DE <his call>.? ?
?
I'm getting back on the air after 45 years away from it.? Using VBand and LCWO.net to improve my speed, but my brain just hears the dits fly by and says "duuuuh!"
?
?
Perhaps next week on 15m???
?
WB0ZJJ - Alan
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Re: #qmx+ #qmx #qdx Documentation updates
#qmx
#qdx
Hi Dale
You might not need the revised manual anyway, if your kit comes with T37-6 toroids. Anyway:
QMX+? - Edit to the parts list to?reflect the fact that four of the toroids might be T37-10 or T37-6
- I changed pages 29 to 31 inclusive, which is section 2.11, to reflect the instructions?for winding if you have a T37-10 toroid for L403.?
- I amended page 32 to include a note that T37-10 toroids may be supplied and also the winding details for those toroids.?
- Page 33 is a new page completely which shows a new diagram for the T37-10 version of the LPFs with the turns count.?
- I made notes in a couple of other places about the FT37-43 being a dull black and the T37-10 being shiny black and NOT to mix them up
- I made some edits to the part of the manual about firmware?updates since?for Rev 2 PCBs it is no longer correct to say that the board comes with no firmware installed.?
QMX (only 60-15m version is affected) - Amendment to parts list notes the possibility of black shiny T37-10 toroids being supplied
- Some notes in a couple of other places about the FT37-43 being a dull black and the T37-10 being shiny black and NOT to mix them up
- Pages 38-40 inclusive are updated to include turns count details?for both the yellow T37-6 case, and the black T37-10 situation.?
QDX (only affects 80-20m version) - Page 11: Amendment to parts list notes the possibility of black shiny T37-10 toroids being supplied
- Page 29: A whole new page that shows the turns counts in table and diagram format for the T37-10 toroids
- Again a couple of notes about NOT mixing up with the dull matt black FT37-43 toroids
The substitution of T37-10 for T37-6 won't cause any performance differences; and the permeability is almost the same, just a turn or couple of turns more are required on the T37-10 for the same inductance. We tested all the builds using T37-10 and they all worked great. No issues.?
A big thing to watch out for is not mixing up the FT37-43 and T37-10, being the same size, and both being black; but really the appearance is quite different, the FT37-43 has a more angular square-ish cross-section, whereas the T37-10 is much more smooth and rounded if you consider it's cross-section.?
73 Hans G0UPL
On Fri, Jan 3, 2025 at 5:30?PM Dale Hardin KS4NS via <joe.dale.hardin= [email protected]> wrote:
Could you list the pages that changed so those of us awaiting our QMX+ delivery can update our assembly manuals?? I already printed out the assembly manual to read while awaiting delivery.
On Fri, Jan 3, 2025, 8:01 AM Hans Summers via <hans.summers= [email protected]> wrote: Hi all
Since T37-6 (yellow) toroids suddenly got scarce, some new batches of QDX 80-20m, QMX 60-15m and QMX+ are now being supplied with some T37-10 (shiny black) toroids. I have updated the QDX, QMX and QMX+ manuals to reflect this.?
--
Dale Hardin
KS4NS
Elberta, AL
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
I have no idea what procedures QRP Labs has before shipping a QMX+,? so take this with as much skepticism as you can muster:
?
My assumption is that they plug in a USB cable to program the STM32F and power the board up, not much more.
That USB cable is just a connection to ground and a couple pins on the STM32F, nothing anywhere near the PCM1804 gets touched.
A fake received signal would have to be driven into pins 7 and 9 of IC403, but that is well isolated from the PCM1804.
The power supplies on the QMX+ are complete, exactly as they will be when shipped to the customer.
I can't imagine any reason for the procedure to physically disturb the PCM1804 in a way that would not happen after a bad chip is replaced.
Any handling at QRP Labs would likely be considerably more benign than that of the typical kit builder who is adding dozens of parts.
My understanding is that the PCM1804 seldom (never?) fails once the PCM1804 has been found to work, either during initial testing at QRP Labs
for recent versions of the QDX and QMX+,? or after Jeff has replaced a PCM1804 (which I'd guess is now mostly on the QMX, since
the QDX and QMX+ have already been tested).? Older kits that did not have firmware loaded at QRP Labs don't have the PCM1804 tested.
?
If the above is correct, it sounds to me llke the assembly house is stuffing bad parts.
?
I could easily imagine that shorting the VCC rail (perhaps due to clearance issues around the front panel) would cause a spike in VCC when the short is removed, blowing the PCM1804.? However, if such failures seldom (never?) occur after the receiver has been found to be working correctly,?
that is probably not an issue.
?
A complete bed of nails would not be required to test the PCM1804 on the currently untested QMX.? I would think it would just require applying VCC and VDD, a USB cable to a host computer that has appropriate test software, and appropriate signals at IC403 pins 7 and 9 that are 180 degrees out of phase.??
Getting this working properly could take several days that Hans does not have, but should not take weeks and a major hardware effort.
?
Jerry, KE7ER
?
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On Fri, Jan 3, 2025 at 05:42 AM, Bruce Akhurst wrote:
I suspect ESD or power supply damage to an incomplete board would not be repeated once fully built.? ESD damage, to ICs in particular, is often evident only after a few weeks or months...
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Re: #qmx+ #qmx #qdx Documentation updates
#qmx
#qdx
Could you list the pages that changed so those of us awaiting our QMX+ delivery can update our assembly manuals?? I already printed out the assembly manual to read while awaiting delivery.
On Fri, Jan 3, 2025, 8:01 AM Hans Summers via <hans.summers= [email protected]> wrote: Hi all
Since T37-6 (yellow) toroids suddenly got scarce, some new batches of QDX 80-20m, QMX 60-15m and QMX+ are now being supplied with some T37-10 (shiny black) toroids. I have updated the QDX, QMX and QMX+ manuals to reflect this.?
-- Dale Hardin
KS4NS
Elberta, AL
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#qmx+ #qmx #qdx Documentation updates
#qmx
#qdx
Hi all
Since T37-6 (yellow) toroids suddenly got scarce, some new batches of QDX 80-20m, QMX 60-15m and QMX+ are now being supplied with some T37-10 (shiny black) toroids. I have updated the QDX, QMX and QMX+ manuals to reflect this.?
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
I suspect ESD or power supply damage to an incomplete board would not be repeated once fully built.? ESD damage, to ICs in particular, is often evident only after a few weeks or months...
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
On Wed, Jan 1, 2025 at 11:22 AM, Hans Summers wrote:
QMX is the outstanding problem. We will find a solution to that too.?
The QMX boards could be tested with some sort of bed of nails test fixture that provided the appropriate test signals for IC403 couldn't they?
Use the CLK2 signal attenuated by R513 with a suitable level and phase shift, then the Rx Audio and Image tests should work.? That's enough to test most of the Rx side on an unpopulated board.
?
Yeah like my QCX-mini test fixture:
?
Yes, that's the sort of thing I was thinking of, not surprised you have already tried it..
?
I understand that it's a lot of work to make but if 1 in 7 of the QMX kits fail because of the PCM1804 problem 100% testing seems essential.? I don't think it's reasonable to keep shipping QMXs untested if that level of failure can be expected, it isn't fair on your customers.
?
Would a test rig that picked up the test signal from R518 and passed it through T401 to the inputs of IC403 work?? Your test harness would provide VCC and VDD and ground, that's 6 or 7 pins.? Run the Rx diagnostics through the USB connection.? This bypasses the LPFs and the BPFs but if they are needed they could be added to the test rig and a single band test done.? The alternative seems to be to connect each board manually using test clips, time consuming and error prone.
?
Chris, G5CTH
?
?
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QMX+ indicates better SWR with antenna disconnected. Issue resolved!
Just in case anyone else gets the same symptoms:-
?
I built a v2 PCB QMX+ and all went well until i went to transmit into a dummy load and the swr protection activated and a high swr was indicated via the terminal program. I checked the load with an swr meter and a VNA and it looked fine. I was somehat surprised that when the dummy load was DISconnected the swr dropped as did the swr alarm!
?
I suspected an error winding T507 so i spent the next 2 nights rewinding it changing the 4 permutations of winding directions but nothing changed. The DC voltages out of the detector diodes matched what the terninal program was saying.
?
On the 3rd night I tried checking resistances, which is hard to do as the windings are DC grounded. I removed T507 yet again and checked the resitances. Measuring across R522 showed 50 ohms. Measuring across the tracks to R520 did not reveal 49.9 ohms! I then measured across the solder pads physically on R520; still not 50ohms. Examination under a USB microscope (i knew it would come in useful one day!) showed a break in the resistive element. I found a 51 ohm resitor as a temporary measure , replaced T507 and all worked perfectly. I subsequently got a 49.9 ohm resitor and put it in.
?
Now you can buy blank QMX+ cases from the ship I have now built an ATU100 into one of them (I have one that would work inside the QMX+ box but that would mean hacking the QMX+ front panel, i will wait till the QMX+ software supports it.) The other case has a 3 x 18650 battery pack () ?which powers the radio well through a dropper diode
?
Dave
G4FRE
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Re: QMX+ No transmit or receive
Joel,
I had a similar incident on a QRP Labs built QMX+. ?It had lower power output from the factory (3 watts or so which is within spec) and then it had no power output. ?I checked T501 and it didn’t look like the wires had taken up solder completely like I want to see. So I reheated that transformer with high heat and longer application. Now I have even higher power output. ?So trusting the soldering procedure to burn off the lacquer coating on the wire is a not so good an idea in my opinion. ?I would at least scrape some of the coating off before soldering. ?And apply more heat for a longer period of time to complete the connection. ?
Just my humble opinion, but with 65 years of learning from my mistakes my method works for me.? ? Be the REASON someone smiles today.
Dave K8WPE
toggle quoted message
Show quoted text
On Jan 2, 2025, at 7:48?PM, Joel Macneill via groups.io <joelmacneill1977@...> wrote:
? Hello Chris, hello Ludwig! Wow I've got some interesting news this evening. Those voltages that I said weren't present yesterday, are present today. I can't explain it but I set the radio up on the workbench again this evening and confirmed that there was no voltage at t401 like yesterday, but I did have voltage this evening. And I have the voltage that I need at pins 7 and 9 of IC 403 and at pin 9 of IC 402. I'm not quite sure how to explain this because I didn't do anything to it. When I noticed the voltages were there, I connected the antenna to the BNC and right away I heard a crackle in my headphones. Now I'm getting signal meter deflection and I'm listening to CW on 80 m. I'm going to listen to the other bands as well but I'm also going to go into the area where I last was yesterday and make absolutely sure I do not have a loose connection. Obviously when I was poking around with the meter, something happened. Maybe my trifilar coil could have an intermittent short? I don't know but I'm hoping to find out and I will let you all know. Thanks very much for all of your input!
73s
VY2KW
On Wed, Jan 1, 2025 at 06:14 PM, Joel Macneill wrote:
1) I have continuity from C526 to the anode of each 1N4007 diodes closest to the rear of the radio and from the cathode of?each.?
Joel, thank you very much for your wishes.
I don't understand the thing with the cathodes. To the anode is ok but to the cathode the same time?
?
All the five points are related to the LPF section. If TX is working well the LPF section should be also ok.
IC408 pin#5 only has 2.5v. ?(idle receive)
?
Sorry, my mistake. 2.5 V is ok.
IC402 pin#9 is 0v,?
IC403 pin#7 is ?0v, pin#9 is 0v
Like Chris wrote: 2.5 V from the voltage devider R401 R402 would be ok.
?
IC402 pin#1 0v and pin#3 0v.?
Ok both connected to GND.
That voltage should also be present at the trifilar toroid coil. Perhaps I am not making sufficient connection there or perhaps it's a short?
Later you found this by yourselfe. I think no short. In case of a short it should be close to 0 V AND the same voltage across R402, C406. It's strange to find 0 V at all the three pins to C402 / C403. It means all three windings are affected. It looks like more than one bad connection and / or connecting the windings in a wrong way.
?
I hope fixing T401 will be the solution.
?
73 Ludwig
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QMX+ - Another build experience
Hi all.
?
I have completed the build of a V2 QMX+ over the festive period, and the? radio? is working very well indeed.? I did have some issues however and wonder if the excellent assembly instructions could be further improved to help others avoid the pain of removing a soldered in LCD display module.
?
The issues I had in the build were mainly with the front panel.? On initial inspection one of the pull up resistors for the was at about 45 degrees to its proper placement and had the metal cap on the end missing.? Fortunately I have a kit of various 0603 resistor values, so no problem to replace.? On visual examination the rest looked to be soldered OK.? When completed however the "Return" button did not work and operation of the encoders was erratic.? After a bit of tracing it was found that the other pull up resistors on the board were damaged.? These are unfortunately located under the soldered in display module which had to be removed.? I did successfully manage this and replaced all the resistors on the board with new ones as they were all suspect - on two of them the values could not be read at all and they had the appearance of being overheated.
I think it would be worth adding a note in the instructions to check the continuity and values of these parts before soldering in the display module.
If there is ever a further revision of the PCB design then these parts could easily be moved to the other side of the PCB so they are accessible.
?
There was another fault on the main PCB.? D501 had received a knock somewhere, probably during the manufacturing process and was not in its proper position with the PCB track lifted.? As the other end (nearer the middle of the board) was soldered OK and did not appear strained I surmise that somehow it got knocked while the board was cooling just after soldering.? The part tested OK and was connected to the rest of the circuit as it should be so I left it.
?
I also think that the assembly instructions should explain the diagnostic tests that should be carried out before putting the QMX on air and what can be considered acceptable and not acceptable.? The assembly instructions can refer to the operating instructions, but could include a simple list of the tests to be done.? If for example there is a fault with a low pass filter, maybe even as simple as? miscounting the turns and having too many, then the PA will see a high SWR even with a good dummy load attached which could result in the PA expiring if an attempt to transmit at full power is made.? This can be seen during the sweep of the low pass filters - the current increases dramatically as the sweep progresses.??
?
Despite the issue with the build quality of the pre-assembled PCB I am very impressed with the radio and am having lots of fun with it.? Brilliant piece of design and engineering.??
?
Dave M0WID
?
?
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
If boards with a failed PCM1804 never fail when the part is replaced, that points to counterfeit parts.?
No, it doesn't; counterfeit parts is only one option; there could also be ESD problems causing it, either during assembly, or subsequent handling somewhere along the line; or there could be problems during our bootloader flashing and testing procedures.? ? And I'd not have them stuffed at that assembly house, make it?a hand add at QRP Labs instead.
Just when I thought I was already having the maximum amount of fun possible per day...
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Chris,
?
I am not sure I am reading the chart correctly, but it looks like there is a significant power output difference for the different bands. ?The line color for band is not in the picture.
?
Did you record output power for each band?
?
73
Evan
AC9TU
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Re: I damaged my QCX mini
Ron,
Thanks I’ll go that one, I appreciate the help.?
Rick KC6UXI
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Re: QMX+ No transmit or receive
Hello Chris, hello Ludwig! Wow I've got some interesting news this evening. Those voltages that I said weren't present yesterday, are present today. I can't explain it but I set the radio up on the workbench again this evening and confirmed that there was no voltage at t401 like yesterday, but I did have voltage this evening. And I have the voltage that I need at pins 7 and 9 of IC 403 and at pin 9 of IC 402. I'm not quite sure how to explain this because I didn't do anything to it. When I noticed the voltages were there, I connected the antenna to the BNC and right away I heard a crackle in my headphones. Now I'm getting signal meter deflection and I'm listening to CW on 80 m. I'm going to listen to the other bands as well but I'm also going to go into the area where I last was yesterday and make absolutely sure I do not have a loose connection. Obviously when I was poking around with the meter, something happened. Maybe my trifilar coil could have an intermittent short? I don't know but I'm hoping to find out and I will let you all know. Thanks very much for all of your input!
73s
VY2KW
On Wed, Jan 1, 2025 at 06:14 PM, Joel Macneill wrote:
1) I have continuity from C526 to the anode of each 1N4007 diodes closest to the rear of the radio and from the cathode of?each.?
Joel, thank you very much for your wishes.
I don't understand the thing with the cathodes. To the anode is ok but to the cathode the same time?
?
All the five points are related to the LPF section. If TX is working well the LPF section should be also ok.
IC408 pin#5 only has 2.5v. ?(idle receive)
?
Sorry, my mistake. 2.5 V is ok.
IC402 pin#9 is 0v,?
IC403 pin#7 is ?0v, pin#9 is 0v
Like Chris wrote: 2.5 V from the voltage devider R401 R402 would be ok.
?
IC402 pin#1 0v and pin#3 0v.?
Ok both connected to GND.
That voltage should also be present at the trifilar toroid coil. Perhaps I am not making sufficient connection there or perhaps it's a short?
Later you found this by yourselfe. I think no short. In case of a short it should be close to 0 V AND the same voltage across R402, C406. It's strange to find 0 V at all the three pins to C402 / C403. It means all three windings are affected. It looks like more than one bad connection and / or connecting the windings in a wrong way.
?
I hope fixing T401 will be the solution.
?
73 Ludwig
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Re: 2m/440 cw/ssb qrplabs kit?
I bought a 6 meter transverter from him last year. I tried it with a?QCX with usdx conversion with 10 m filtering and power reduced to 300 mw. Made 6 contacts on FT8?and then the band went dead before I had a chance to try it for SOTA.? Puts out about 10 w.?
-- Jginaz
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
Jeff Moore has never seen a PCM1804 fail after he’s replaced it and he replaces quite a few of them. Jeff is sourcing replacement devices from Digikey and they’re also available directly from TI.com. I tend to agree there’s something amiss in the CM’s procurement process.
Tony
If boards with a failed PCM1804 never fail when the part is replaced, that points to counterfeit parts.? And I'd not have them stuffed at that assembly house, make it?a hand add at QRP Labs instead.
?
Jerry, KE7ER
?
?
On Thu, Jan 2, 2025 at 07:56 AM, Jerry Gaffke wrote:
When final test detects a problem with the PCM1804, do they replace it with stock you buy from directly from TI?
Do these parts also fail in the same way at a 15% rate?
It could be your assembly house is sourcing what they believe are parts from TI, but they are counterfeit.
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Evan
I did not really figure out why the peak voltage gets worse at lower frequencies.? In general these peak voltages are caused by the harmonics reflected back into PA transistors by the LPF.? It could be how the higher harmonics stack up because of the particular phase of the reflected higher harmonics.??
?
The plot shows peak voltage vs SWR for 40m to 160m bands
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
If boards with a failed PCM1804 never fail when the part is replaced, that points to counterfeit parts.? And I'd not have them stuffed at that assembly house, make it?a hand add at QRP Labs instead.
?
Jerry, KE7ER
?
?
On Thu, Jan 2, 2025 at 07:56 AM, Jerry Gaffke wrote:
When final test detects a problem with the PCM1804, do they replace it with stock you buy from directly from TI?
Do these parts also fail in the same way at a 15% rate?
It could be your assembly house is sourcing what they believe are parts from TI, but they are counterfeit.
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Re: Release of version 1.2 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp)
#ABS
#ATU
#PSU
#QMXplus
Dear Stan,
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please put me on the 2nd list, if you descide to have one.
Best regards,
Stefan
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WB0ZJJ-Alan
Dale Hardin KS4NS
Bruce Akhurst
David Wilcox K8WPE