Re: QMX, T401, A 20cm length of wire should have about 60 twists. It is not critical.
I fully agree with the method Alison suggests but I have also made a white mark on the drill chuck which makes counting the turns much easier. I don't think the type of paint is important, Snopak would work.
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Re: QMX+ Only black squares on the LCD
Many thanks Don,
But I can't find the origin of the problem.
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I think I need a buck boost converter
Hello,
I have a QMX and plan to power it with a Bioenno BLF-1209 12v 9Ah LiFePO4 battery. I think I need a buck boost converter to keep the battery voltage at 12 volts maximum. Can anyone suggest a buck boost converter?
?
73,
Tom, N8EUI
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Re: QMX high SMPS bias current w/no transmit on two bands
Paul,
?
Good that you found the problem.
The symptoms and cure might be instructive here, as there's a couple mysteries.
?
Firmware should probably be changed to simply state the TX_BIAS voltage
instead of estimating the bias current from that voltage.
I'd find that much less confusing.
?
?
If L505 were shorted when running the diagnostics, then Q509 would draw too much current?
from TX_BIAS and the TX_BIAS voltage should fall, the diagnostics would report this low voltage
as a low TX_BIAS current since it assumes all the hardware is in working order.
?
Instead,? the symptom you report of a too high bias current (actually a too high bias voltage
and thus perhaps no bias current) suggests that L505 was open when running the diagnostics.
Perhaps removing L505 from the board before using the ohmmeter changed the open to a short somehow?
Perhaps in addition to a shorted L505 there was a bad solder joint at L505 that prevented any current flow through it?
Weird.
?
?
Also, I'd guess the SMPS for TX_BIAS around Q502 and L501 does not attempt to adjust
the PWM_BIAS duty cycle to regulate the voltage.?
The processor just feeds it a fixed PWM_BIAS and then reports the measured voltage
from ADC_BIAS in the diagnostics.??
?
(I'm looking at QMX+ schematics, I assume all of that is the same for the QMX)
?
Jerry, KE7ER
?
?
On Sat, Mar 8, 2025 at 06:53 AM, Paul Harker wrote:
Thank you Jeff.
It appears that L505 is the culprit. L505 continuity is good; too good. It measured at roughly 0.3 ohm after accounting for the meter leads. The inductance measures less than 0.2uH.
I swapped in L509 from LPF_2 to verify that there wasn't anything else wrong before placing a parts order. With the inductor replaced the 40/60 bands work perfectly.
??
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Re: Professional Morse Decoder
your describing todays AI, the curve is already beginning to go vertical. It will understand you better than you understand yourself, you certainly won't have to be precise with the prompt. I've noticed that already with Claude 3.7 sonnet.
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Paul.
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Re: QMX, T401, A 20cm length of wire should have about 60 twists. It is not critical.
Wow. That's much tighter than my twists were (about 2X as may turns/inch, I'm thinking), and my QMX+ seems to be doing just fine.?
As for soldering magnet wire, I scrape and tin before putting the toroids into the PCB. If fitting the wires through the hole is an issue, you can use solder braid to get excess solder from the wire. Getting the enamel off for a good solder joint is a pain. I had to redo a few connections 'cause I didn't have the enamel off as well as I thought I did.
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Steve
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Re: QMX high SMPS bias current w/no transmit on two bands
Thank you Jeff.
It appears that L505 is the culprit. L505 continuity is good; too good. It measured at roughly 0.3 ohm after accounting for the meter leads. The inductance measures less than 0.2uH.
I swapped in L509 from LPF_2 to verify that there wasn't anything else wrong before placing a parts order. With the inductor replaced the 40/60 bands work perfectly.
??
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Re: QMX+ Only black squares on the LCD
Hi Andre,?
Hopefully you will have better luck than me.
?
--
73,
Don K0DBL
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AND, QMX-PLUS's XMTR ALSO works using just a string of clip leads !
Now, where did I put that old mic ?
72,
Bill, N4QA/4/QRP Oak Island ( OKI ), North Carolina, U.S.A.
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QMX+ Only black squares on the LCD
When powered the QMX+ on 9V with a regulated ITT power supply with current limiter, there are only black squares on the first line and nothing on the second. The current is 190mA.
I checked the soldering and the assembly and did not find any errors. I connected an LED with 220ohm to ground on the wires of LCD-D4 and D7, there is nothing flashing.
Ajusting the LCD contrast trimmer have not solve the problem.
By listening to the 25MHZ TCXO I can hear the signal on the IC7300 receiver. I think the STM32 is not working.
What else can I do??
André F6APU
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Re: QMX high SMPS bias current w/no transmit on two bands
The TX bias current measurement is actually a voltage measurement in the Tx bias circuitry. ?This will translate directly into a current if all is working well. ?When it reads high like this it usually means that lpf bank is not switching on.
?
I’ve seen this pretty often. ?In your case check Q509 & L505. ?Also check continuity across both L506 & L511. ?The two 1N4007s seldom fail. ?But check that they are installed correctly and not cracked. ?Q505 is the mosfet that turns it on. ?Its gate should be at about 3.3v. ?Its drain and source should be very near GND or 0V. ?L505 should measure about 1.8 ohms in circuit (power off!). ?They can crack when installing. ?
good luck. ?Let us know what you find.
?
--
73
Jeff Moore
W1NC
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Re: QDX half Frequency output ??
As others have said, it's fairly common to see misreports from
systems where the operator or the software has not kept up.
?
Nothing to worry about.
?
73 de Andy
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Re: Professional Morse Decoder
On 07/03/2025 15:35, Jerry (KB2GCG) via groups.io wrote: Any chance of integrating this with a CW sender Just get the AI to do that.
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Craig, the rig is definitely not junk, it just needs tweaking somewhere. One place I would look is at all the solder joints. Check for cold joints, solder blobs or tiny solder bridges (use a jewelers loup, magnifying glass or similar for this). Reheat all toroid wires where they go through holes to ensure all the insulation is burnt off. Then? I would look carefully at the software. If nothing here solves the problem, do as I did (twice) and contact Jeff Moore (W1NC). He is the expert par excellence.
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Re: Professional Morse Decoder
Jerry, the source for your audio is your Rigs loudspeaker and I designed the program so that you could just hold the microphone a few centimetres away and it would work.?
what about connecting a Y connector to your audio output and one lead of the Y to your mic input, the other to your phones?
?
?
Paul DJ0CU
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Re: Professional Morse Decoder
On Fri, Mar 7, 2025 at 07:33 AM, Paul Harrison wrote:
Yes your days as code producer are numbered, we will just be program designers leaving the heavy Lifting to AI which can complete a project in seconds that would take us weeks or months. However I still think it is imperitive that you have a very good knowledge of AI and coding to get the best out of it. Remember this is the worst AI will ever be.
I'm not convinced.? What seems to happen is that AI generated code has mistakes where things aren't described to it correctly.? There will be a need to specify the description of what's needed so clearly that it can't misunderstand and that all eventualities are covered.? Once you do that all you have done is define a new computer language, one for talking to the AI.
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Chris, G5CTH
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Re: QDX half Frequency output ??
WSPR reports from a wrongly set receiver/reporter set up. ? You’ll probably see others receiving the signal correctly.
?
Don’t panic?
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Re: QDX half Frequency output ??
Rick,
?
I have seen that frequently on my band hopping WSPR station on multiple bands running my old FT817 at a half a watt under the control of a Raspberry Pi4. I have no explanation for it and just shrug it off.
?
I have also seen it on my 10m QCX Mini.
?
73
-Mike
?
?
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Re: Professional Morse Decoder
To be clear, a Chromebook does allow you to choose between perhaps an internal microphone,
a bluetooth headset, or a microphone plugged into the 3.5mm jack, if such devices are detected.
Those are all normal microphone inputs that it would have to support.
?
However, I saw no way to choose the audio going out to my headphones as the source for "microphone" on the Chromebook.
Ubuntu Linux does allow this, as described in my previous post.
?
Jerry, KE7ER
?
On Fri, Mar 7, 2025 at 06:41 PM, Jerry Gaffke wrote:
This input device setting is not a browser setting, it is an operating system setting and will be different for every flavor of machine.
Such a setting does not seem to exist under ChromeOS on a Chromebook.
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Hi. I am new to this group and have a question on the QMX 60-15.
I recently finished my build and while the receiver and transmitter work, something is not correct. Digital mode is totally useless. The receiver sensitivity is low, and the bandwidth is extremely broad. Not like CW. I could not have something not set up correctly for digital as I have factory defaults currently.
I also have a dead spot on 20 meters at 14.025 where the noise, internal and external, goes completely away. That spot is about 5KHZ wide.
?
I was going through the hardware tests and noticed that when I run the ADC I/Q test, my plot is ok for I channel but Q channel is very stepped in appearance from that of the picture in the operator's manual.
Some of the other test look OK. I did check my winding of the trifilar wounded transformer and that is correct as tested with my ohm meter. However, when installed on the board there is no way to make sure it has been installed correctly. All wires are at ground.
?
Any thoughts greatly appreciated.
TU
Barry
K3BO
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Steve H
Bill, N4QA/QRP
Grant
Bruce Akhurst