New Chat: Serial Number Recovery w/o Order Number
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A new chat has been created:
Not sure where to ask this, so will try here:
My wife purchased a 40m QCX-Mini kit in the fall/winter of 2023 as a Christmas Gift. She ordered as a guest and got rid of emails related to the purchase, so I don't think I have a way to get the order number.
Is it possible to lookup the order/serial number based on an email address and/or a delivery address??
I have an itch to laser engrave my enclosure with the S/N, band, and options (TCXO and AGC). This is the main reason I'm interested in recovering the S/N.
Thanks!
Ben (KF0KXW)
By:
balexander87@...
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Stan,
?? You are correct, I have the terminology of the two swapped.
Thanks, Gary
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Re: QMX+ lucky streak ended
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Good luck finding the problem.? I enjoy building kits and often I have to fix them
A couple of tips I've picked up on the forum
1) Use Quickchip low temperature solder to remove parts. 2) Use Bluetack to hold smd parts while soldering.
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Re: QMX+ lucky streak ended
On Tue, May 27, 2025 at 06:52 PM, pgramsey, N9LFF wrote:
On Tue, May 27, 2025 at 02:58 PM, Stan Dye wrote:
Was there supposed to be a link there?
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73, Dan - W2DLC
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Re: QMX+ lucky streak ended
On Tue, May 27, 2025 at 02:58 PM, Stan Dye wrote:
Was there supposed to be a link there?
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Re: QMX+ lucky streak ended
Agreed. After 50+ years of EE debugging, I should be able to find it. Replacement parts might be another issue.
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Thanks for the offer!
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Brent DeWitt, AB1LF
Milford, MA
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It's fine to state what ideal workmanship might be, but let's not get everybody ripping their QMX apart to apply more solder.
That sort of thing is worth worrying about on a Voyager probe or a jet navigation system.
But of the potential QMX failure modes, verifying that solder falls out the far side of a through hole is down at the very bottom of my list to worry about.
Almost all QMX soldering issues are due to improper solder adhesion to the enamel covered wire on the toroids, better to concentrate on getting that right.
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The important thing is to make sure the solder flows properly across both part lead and board pad to ensure you don't have a cold solder joint.
Another important thing is to not keep the soldering iron on that joint so long that you damage a part, or the top pad adhesion to the board.
Given that some will not have the quite right soldering iron temp and the fact that we might have 6 internal ground planes on some
through holes, getting solder to flow through may be especially difficult.
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And as I've said before, if you plan to blow the BS170's you're best of not even running those leads through the board.
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Jerry, KE7ER
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On Tue, May 27, 2025 at 02:47 PM, Tony Scaminaci wrote:
On Tue, May 27, 2025 at 4:16?PM Donald S Brant Jr via <dsbrantjr= [email protected]> wrote:
The NASA Workmanship standards show 100% fill of plated-thru holes as preferred workmanship practice:
"Populated plated through holes (PTH) should exhibit a vertical solder fill of 100%, with a fully formed fillet on the solder side, and evidence of 100% wetting on the component side lead, barrel, and pad."
Acceptable:? " A slight recessing or shrinkback of the solder into the PTH below the solder pad is acceptable, providing the lead and pad exhibit wetting and the shrinkback is slight."
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My old links to the standards no longer work for whatever (hopefully not nefarious) reason, fortunately they are still available: ?
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I know that we are not making space flight hardware, but we may as well take advantage of the hard-won information available and use best practices when practical.
73, Don N2VGU
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Re: 50 Watt Power Amplifier - Low Power, High Harmonics
#50w
#50wpa
A comment made by Evan Hand raised two questions in my mind:? how close is Vth for a batch of MOSFETS ordered at the same time? And is one of those Atmel-based component testers useful for matching MOSFETs??
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Hans Summer's explanation of the design of the 50 watt amplifier emphasizes that close matching is not required. I wondered what spread of threshold voltage I would see.? Since I'm not swapping out the IRF510s in the kit I built, at least they can have some educational value before being put into the parts bin.
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I? used a simple circuit I found for testing Vth - gate and drain together, and a 2. 2 K resistor from a +15 volt supply to drain.? The MOSFET conducts only enough to draw about 5 mA(+/-) through the resistor. Of the ten BS170 I bought, the highest voltage measured was 2.453V, and lowest was 2.396. Four of them were between 2.42 and 2.43 volts.? I also got six IRF510s and these spanned from 3.358 to 3.385 V when tested with a 2.2k resistor.?? I didn't make any special control of the temperature of the devices under test.
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The interesting part to me is that the component-guesser agreed with the test circuit measurements, though it only resolves to 0.1 volts. So it would be useful for at least a rough match of Vth, or at least identifying candidates worthy of closer testing.
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Re: 50 Watt Power Amplifier - Low Power, High Harmonics
#50w
#50wpa
I did some testing Sunday evening to explore the performance envelope of the 50 watt amplifier and QCX+ combination. My friend who will be operating the set will be using batteries, so I wanted to explore the full range of voltages.
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My setup was a variable bench power supply, switch-mode variety, a mystery brand "Uniroi RC305" similar to many.? Current limit turned up? the limit of 5 amps, and using the supply's internal metering which I'd previously checked to be in agreement with my Fluke 115. RF power measurement? was by using my Siglent scope to measure peak to peak volts, squaring that and dividing by 400.? Dummy load was another mystery brand purchased on-line, said to be good for 10 watts continuous and 100 watts peak - so I kept my power measurements short and gave the dummy load a minute or so to cool between dits.? Exciter was the QCX+ at a constant 13.8 volts from a separate supply, giving about 4 watts into a dummy load. Test frequency was 3520 KHz.
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10 V 5.3 W
12 V 7.6 W
13.8 V 9.9 W
15.0 V 11.6 W
17.0 V 14.8 W
19.0 V 18.3 W
21.0 V 21.9 W
24 V?? 27.9 W
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I did have a shortwave receiver running in the next room and didn't notice any odd sounds coming from it, and the carrier looked clean visually.? I did not do FFTs at every voltage,? the 8-bit scope has a pretty limited range and I didn't think it would assure being 40 dB down at the second harmonic. I'll do this at 13.8 V just for educational value.
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I then put the QCX+ on the variable supply and the amplifier on fixed 13.8 V - sweeping the QCX from 10 to 15 volts gave no difference to the power output of the 50 watt amplifier, which remained at 9.9 watts.
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My new IRF510s came in today but in view of the recommendations of Aki JO4MTH, I don't think I'll swap transistors out.
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It's been very educational building and testing this kit. Thanks to the group for comments. Knowing when to stop tweaking is a vital skill.
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Bill
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Re: QMX+ lucky streak ended
Ouch.? No fun.
Something internally is shorted.? Since you were receiving, it is likely in the power supply circuitry, although it is possible that another component failed.
See this wiki page, and in particular the first section 'From 0 to RK', and the test setup and links under searching for a failure.
This is a relatively new wiki (work in progress) that Ludwig has put together to help bring together the various debugging resources on the wiki.
Let us know if that helps, and if you still have questions, don't hesitate to ask.
Stan KC7XE
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I agree completely Don. I spent 17 years in a mil-spec contracting organization and full 100% fill on the opposite side of the board was a requirement. Many a board was sent back to assembly by our QA group for violations of this standard.
On Tue, May 27, 2025 at 4:16?PM Donald S Brant Jr via <dsbrantjr= [email protected]> wrote: The NASA Workmanship standards show 100% fill of plated-thru holes as preferred workmanship practice:
"Populated plated through holes (PTH) should exhibit a vertical solder fill of 100%, with a fully formed fillet on the solder side, and evidence of 100% wetting on the component side lead, barrel, and pad."
Acceptable:? " A slight recessing or shrinkback of the solder into the PTH below the solder pad is acceptable, providing the lead and pad exhibit wetting and the shrinkback is slight."
?
My old links to the standards no longer work for whatever (hopefully not nefarious) reason, fortunately they are still available: ?
?
I know that we are not making space flight hardware, but we may as well take advantage of the hard-won information available and use best practices when practical.
73, Don N2VGU
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Everything has gone textbook right for my QMX+ (kit built) for a few weeks now, but I knew it couldn't last.
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I was receiving with the USB connected to a Raspberry Pi 4 running WSJT-x and it seemed to be working fine.? Then I looked back and the display was dark. Pushing the startup knob drops the regulated voltage to 11v and current limit of 600+mA, which goes back to zero mA when the push knob is released. No idea what happened, but it's down to the basement "bench" to take a look.
Film at 11.....
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Brent DeWitt, AB1LF
Milford, MA
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The NASA Workmanship standards show 100% fill of plated-thru holes as preferred workmanship practice:
"Populated plated through holes (PTH) should exhibit a vertical solder fill of 100%, with a fully formed fillet on the solder side, and evidence of 100% wetting on the component side lead, barrel, and pad."
Acceptable:? " A slight recessing or shrinkback of the solder into the PTH below the solder pad is acceptable, providing the lead and pad exhibit wetting and the shrinkback is slight."
?
My old links to the standards no longer work for whatever (hopefully not nefarious) reason, fortunately they are still available: ?
?
I know that we are not making space flight hardware, but we may as well take advantage of the hard-won information available and use best practices when practical.
73, Don N2VGU
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Re: Elecraft T-1 tuner usage
MENU/Hardware test/Tune SWR/Select
And maybe one more press to start. Press exit to return to normal
operation
On 27/05/2025 16:18, Braden Glett via
groups.io wrote:
toggle quoted message
Show quoted text
I attempted this, but quickly realized I don't understand how
to do steps 1a and 3.?
The manual, as usual, didn't shine any light on how to use
the Tune SWR function.?
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On a similar note, I would like to interface my QMX+ with my Hardrock 50 or my KXPA100 amplifiers, and having a way to automate the band switching would be of interest to me; PTT switching is handled natively already.
Apparently the HR50 "understands" KX-3, FT-817 and Xiegu serial band information formats, KXPA understands KX3 serial data and Icom and Yaesu band voltages.
I also have the QMX+ dev kit so have access to the BPF and LPF signals.? One of the clever folks on this?forum must have figured this out already, or perhaps there is a commercial product out there that I haven't found.
Would anyone who has figured it out mind sharing your approach???
Thanks and 73, Don N2VGU
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On Tue, May 27, 2025 at 01:37 PM, gary poland wrote:
I initial tried tweaking the LP filters with little effect. They are tightly wound and because of the tap little movement is possible. So yes I played with the spacing of the windings of the band pass filters. Most are completely spread across the entire toroid, no turns were added or removed.
Gary, maybe we just have a different understanding of LPF vs BPF.? On QMX/QMX+ only the bandpass filters have taps.? The low pass filter toroids (vertically mounted on QMX+) do not have taps.
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Re: Elecraft T-1 tuner usage
Here are more details on the Tune SWR function for you:
Step 1a) after getting to the Tune SWR menu, turn the tuning dial.? That's how you tune to a frequency anywhere, including inside the Tune SWR function.
Step 3) press the left button (select button) - this starts the QMX transmit/tune signal at the frequency selected above.?
Step 4) a second press of the same left button will stop it again, so you can start/stop multiple times while still in the Tune SWR function.
And as a bonus, if you want to tune on another band, without leaving Tune SWR, you can turn the 'volume' dial to change bands quickly.
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On Tue, May 27, 2025 at 01:18 PM, Braden Glett wrote:
I attempted this, but quickly realized I don't understand how to do steps 1a and 3.?
The manual, as usual, didn't shine any light on how to use the Tune SWR function.?
As usual?? This is one of the best manuals I have ever seen for a very inexpensive QRP radio.? But you are correct, it does not include all details.
But most of what it does not include is easily found by turning the knobs and pressing the buttons.
Stan KC7XE
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Most builders solder on the bottom of the PCB. However, plated-thru holes usually wick solder up into the hole, often being visible from the top of the board. I think quality PCBs and good soldering techniques produce the "wicking effect" most of the time.
Jack, W8TEE
On Tuesday, May 27, 2025 at 02:54:52 PM EDT, Roy Ashkenaz via groups.io <cqk2rma@...> wrote:
I've successfully have built many kits, but I always wondered....
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I push the thru-the-the board component leads from the top of the board thru to the bottom of the board.
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I've always wondered, for thru-the-board components, should I solder the component thru lead and pad on the bottom of the board, or should I solder both sides of the component lead (top and bottom of the board)?
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And if I only solder the component thru lead and pad, should I see solder flow on the top side of the board/lead?
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Thanks, Roy de K2RMA
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Stan,
? I initial tried tweaking the LP filters with little effect. They are tightly wound and because of the tap little movement is possible. So yes I played with the spacing of the windings of the band pass filters. Most are completely spread across the entire toroid, no turns were added or removed.
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73, Gary
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Daniel Conklin
Brent DeWitt
Donald S Brant Jr
jjpurdum