Re: QMX+: RWTST how to wind T501
You are correct in your statements regarding the photos.? It is symmetrical.
The 3:2 comes in the following steps, when you cut the twisted loop (becomes the two ends of the primary), and re-twist the correct two of the other leads to become the center-tap of the primary.
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
Hi Sardar,
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please don't get my above comment wrong. I fully agree with you, it's a low cost, low effort solution, which can work for most cases.
I just wanted to mention that this is not a "consumer proof" solution. Okay, as licensed amateur radio operator you should know what you're doing.
My Agilent bench power supply is not suited for this application. As soon as I switch the output off, it drains the battery.
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Anyhow, I think such a discaimer on the GitHub would be a good idea.
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Re: Brand Reccomendation for 28AWG wire?
Transformers from old wall power bricks have good wire in them a lot of times.?
--
73, Dan - W2DLC
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Re: Brand Reccomendation for 28AWG wire?
Great save.?
You have nice tight winds on that transformer. Perhaps a bit more than the recommended 3 per centimeter being enough.?
I too snapped a wire on that assembly on my first QMX build. I did have a tighter twist ratio than the recommended amount. BUT, I had checked and smoothed as necessary the toroids edges because Hans had included that suggestion in the QMX instructions. (Though I don't see that specific guideline in the QMX+ assembly manual.)
But my snap occured when unwinding the twists, and spreading? the ends for ID'ing and aligning the ABC pairs.?
I rewound mine with less twists and decided to GENTLY press out the curled twists in each leg with a small pair of flat faced needle noses pliers. That was before moving on for ID'ing, stripping enamel and aligning the pair order for insertion.?
That technique worked for the retry.? And on two additional QMX+ builds and on my new QDX LB.
GREG KI4NVX?
On Mon, Nov 18, 2024 at 1:09 AM, Carol KP4MD <kp4md@...> wrote: I strongly suggest, Hans, that you please add a warning in your assembly manuals for builders to deburr their ferrite cores.?
I neglected to do and also snapped a wire off T401, never before having seen ferrites with such sharp edges.?
As I spread the leads of the trifilar T401 toroid to mount it on the board, one of its leads broke off where a sharp edge on the ferrite had nicked it.?
I was lucky to successfully splice back the broken lead with solder and to secure it with a hemostat while soldering T401 onto the board.?
The manual and support are otherwise excellent.? This was my only mishap while building the QMX+.?
The radio lit up without a puff of smoke and is now on the air!
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Re: QMX+: RWTST how to wind T501
It's symmetrical.
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On Mon, Nov 18, 2024 at 05:40 AM, Giuseppe Marullo[iw2jww] wrote:
I don't understand if steps 11 and 12 are producing a "symmetrical" result.
I m winding and everything is fine until step 10 included.
Figure on step 11 seems to be as step 11 is already executed and half way to what is expected in step 12.
Figure on step 12 shows what it should be after step 12 execution.
Is okay to consider step 11 and 12 producing a symmetrical winding? Or one twisted wire should pass once more compared to the other?
If it is symmetrical still I don't get where the 3:2 ratio is created, could someone please shed some light?
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Re: MFJ-1984LP Antenna 80m-10m EFHW 30W
On my homebrew shortened EFHW, I built a coil following step 10 of the instructions from K6ARK "QRP/20w 49:1 EFHW Instructions":
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73 de Todd W2TEF
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
With 12.5V supply the current is about 1.2 A, with empty batteries this would be higher.
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Another potential issue: The battery voltage is directly applied to the connector. Not all power supplies like "active" loads, which can send current back.
Many regulated lab bench supplies start sinking significant current, if they are switched off or the output is disabled. This can damage the power supply.
I connected my power supply via a Schottky diode, but this is another 0.3V drop.
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So overall the charging of the batteries is not an optimal fit.
They would be charged 100% at 12.8 V, which is already above the recommended supply voltage of the QMX+.
I operated my QMX (without +) without issues at (beefy RC airplane) 3s LiPo, as there is always some voltage drop. If the batteries should be charged and the system operated the overall voltage seems to high for the QMX, or too low for the batteries.
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Dirk,
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Thanks, yes, I agree with your observations.
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Few thoughts about it:
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1. Well, during past 3 years of usage of this circuitry I have never experienced power supply or battery damage. Except the voltage drop issue of course. I have been charging it using few different ways, including my bench regulated power supply (Yaesu FP1030A).In the field few times I tested the charge by directly plugging a biouenno battery to the qmx+ back connector.?
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2. I offered this BMS unit for this design having a field operation in mind where there is no bench power supply. I will add to the instruction the recommended power supply that Barb offered few messages above. At the shack or on the road that power supply can be used.
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3. If we worry about exceeding 12V while charging - we can keep QMX+ off during charging cycle or in RX mode only.
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4. I am pretty sure Hans will come up with his own state of the art and affordable solution for both ATU and the battery. I will be the first to buy it. Until then I can cope with this one.
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5. I am open for testing/designing an alternative solutions/ideas that would be efficient, cheap and will not introduce noise.
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6. I will add a disclaimer to GitHub repository readme that adopters are trying these experimental solutions at their own risk and I do not carry any repsonsibility for their material loss or loss of health.
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--
73,
Sardar (AC8L, 4K6SA, VA3DUA).
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Re: Error in 5V SMPS diagnostics
Thanks Hans,
My 220k is in parallel to R113 and it looks as if I'm lucky with the tolerances on the 3.3V supply.? I wasn't sure if there were low PWM limits as well.? Now all that's needed is put the BS170s back.
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Chris
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Re: Erratic ADC/IQ sweeps
I also have a problem with bad image rejection. I/Q signal sweep shows anequal amplitude of I and Q signals. I first checked and rewound the trifilar transformer T401, but without results.
Today I made measurements with an oscilloscope and a signal generator. Signals on pins 1&7 on IC405 and IC406 shows equal amplitude and correct phase shift. I checked the same signals on the PCM1804 pins.
Can I conclude that I also have a problem with the PCM1804 chip?
You can find attached my image and I/Q sweep and oscillograms from pins 1&7 on IC405 and IC406.
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73 de Zrinko Ivan, 9A7AM
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
The batteries are now charging in the QMX+.
With 12.5V supply the current is about 1.2 A, with empty batteries this would be higher.
?
Another potential issue: The battery voltage is directly applied to the connector. Not all power supplies like "active" loads, which can send current back.
Many regulated lab bench supplies start sinking significant current, if they are switched off or the output is disabled. This can damage the power supply.
I connected my power supply via a Schottky diode, but this is another 0.3V drop.
?
So overall the charging of the batteries is not an optimal fit.
They would be charged 100% at 12.8 V, which is already above the recommended supply voltage of the QMX+.
I operated my QMX (without +) without issues at (beefy RC airplane) 3s LiPo, as there is always some voltage drop. If the batteries should be charged and the system operated the overall voltage seems to high for the QMX, or too low for the batteries.
?
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QMX+: RWTST how to wind T501
I don't understand if steps 11 and 12 are producing a "symmetrical" result.
I m winding and everything is fine until step 10 included.
Figure on step 11 seems to be as step 11 is already executed and half way to what is expected in step 12.
Figure on step 12 shows what it should be after step 12 execution.
Is okay to consider step 11 and 12 producing a symmetrical winding? Or one twisted wire should pass once more compared to the other?
If it is symmetrical still I don't get where the 3:2 ratio is created, could someone please shed some light?
TIA
--
Giuseppe Marullo
IW2JWW - JN45RQ
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Hi Aki,
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Thank you for the reply. I will review my capacitor selection.?
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73 de Jared N7MAW
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Re: Error in 5V SMPS diagnostics
Hi all
The firmware reports an error if the duty cycle is higher than the internal model's maximum for the applied input voltage, in the attempt to raise the supply rails (3.3V and 5V) to their target values.?
If you apply external?3.3V and 5V linear supplies for some reason (not recommended) then the situation depends on whether the processor measures the voltage?as above or below 5V (or 3.3V in the case of the 3.3V supply rail). Since the exact values depend on component tolerances, if you do nothing but build it as is, it may work, or it may not, depending which direction the component tolerances lean in, in your particular case. The PWM duty cycle will either be zero (if the linear supplied voltage is measured as over 5V) or maximum (if the linear supplied voltage is below 5V) because essentially the system has become open loop. You are forcing the output (the supply rails) to a particular value but the control loop now has no control over it, but it doesn't know it has no control over it and is still trying.?
The correct solution is to place a 100K resistor in parallel to R112 (3.3V supply) or R113 (5V supply) in which case when the rails are at 3.3V and 5V respectively, the microcontroller will always measure them as higher than they really are, so will think that they are too high, and will reduce the PWM duty cycle to zero and not cause any error.?
On Mon, Nov 18, 2024 at 3:43?PM Dave (G8PTN) via <daveg8ptn= [email protected]> wrote: Hi Chris,
I am not sure what the criteria is for the ¡°Error¡± status on the SMPS, perhaps it is measured voltage and duty cycle.
It does seem a bit odd that the 3V3 supply does not report the error even though Duty cycle = Duty max.
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Anyway, the change seems valid.
Assuming the reported voltage on the PUTTY screen = 2 x ADC_5V, the calculated VCC voltage is the same for both of your arrangements.
In the case with the parallel 220k, it stops the ¡°Error¡± state and the PWM signal should be turned off.
General equation:
VCC = (PUTTY_V / 2) x (1 + R2/R3)
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Without the parallel 220k:
VCC = 4.99/2 x (1 + 22k/22k) = 4.99 V
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With the parallel 220k:
VCC = 5.24/2 x (1 + 20k/22k) = 5.00 V (VCC is at the same voltage, but the firmware will calculate 5.24V as you have shown)
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As you say, ?perhaps forcing the PWM signal off is advantageous, but I suspect if the firmware thinks the voltage is too high, the status may also show an ¡°Error¡±.
73, Dave
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
Hi Sardar,
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yes, the reset activates the bypass mode and from my point of view this is sufficient.
Today the fresh batteries arrived and I'll start testing that part.
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73
DK7CVD
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Re: Error in 5V SMPS diagnostics
Hi Chris,
I am not sure what the criteria is for the ¡°Error¡± status on the SMPS, perhaps it is measured voltage and duty cycle.
It does seem a bit odd that the 3V3 supply does not report the error even though Duty cycle = Duty max.
?
Anyway, the change seems valid.
Assuming the reported voltage on the PUTTY screen = 2 x ADC_5V, the calculated VCC voltage is the same for both of your arrangements.
In the case with the parallel 220k, it stops the ¡°Error¡± state and the PWM signal should be turned off.
General equation:
VCC = (PUTTY_V / 2) x (1 + R2/R3)
?
Without the parallel 220k:
VCC = 4.99/2 x (1 + 22k/22k) = 4.99 V
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With the parallel 220k:
VCC = 5.24/2 x (1 + 20k/22k) = 5.00 V (VCC is at the same voltage, but the firmware will calculate 5.24V as you have shown)
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As you say, ?perhaps forcing the PWM signal off is advantageous, but I suspect if the firmware thinks the voltage is too high, the status may also show an ¡°Error¡±.
73, Dave
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Re: MFJ-1984LP Antenna 80m-10m EFHW 30W
Good day
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?the setup I¡¯ve seen has the coil about 6ft from the transformer. 6-7 turns on 1 inch form. ?This should pull upper bands down into CW portions nicely.?
take a look at the ¡°my antennas ¡° brand of EFHW available I believe they show this. There are also some YouTube videos by an N4 call that shows how to do the coil.?
several others for sure. I guess it originally came from a German antenna book?? Not sure on that. But it works! ?Good luck. Sorry I don¡¯t have more specifics. I¡¯m on the move but figured I¡¯d send along what I could remember. I¡¯m sure someone will be along who will fill in more blanks or correct me :).?
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It doesn't seem to be bricked because the MCU is running well enough to connect to the PC as a drive.
I would try PUTTY.? There are guides about this in the manuals. but basically
- install PUTTY
- Connect the USB between your QMX and the PC.? Apply power, 7.5V is plenty.
- Find out the serial port that your QMX is.? Device Manager will give you this.
- Run PUTTY, set the COM port in the Serial line box and the speed to 19200, Connection type to Serial.
- Open Putty, you should see a blank screen with a small green square at the top.? Press Enter and you see data from the QMX.
- If you get that far and are getting text on the screen use the manuals to help sort things out.
The lack of a display may be because of something else but the diagnostic screen in particular should help you (and us) find out what is happening.
Once we know what's happening there's a better chance of fixing it, a lot better than guessing.
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BTW the 1.65V you measured is half the 3.3V power supply which is supplied on a different pin (ADC_3V3) It's supposed to be that.
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Re: Automatic Antenna Tuner, Internal Battery with a charger and built-in speaker for QMX+. Open Source.
you might have missed it with all the post coming in on this topic.
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I made a stupid mistake during the first measurement and the reset powers the relays off.
Only relay 1, which toggles the capacitances between antenna and transceiver side powers up.
Dirk,
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I definitely did not miss your report. Just wanted to clarify it¡¯s material implications.
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This is my understanding:
1.Reset function of ATU works as expected, putting ATU in a bypass mode when autotune is off.
2.Bypass function of ATU is less critical for this project as though before.
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Please correct me if I¡¯am wrong.
--
73,
Sardar (AC8L, 4K6SA, VA3DUA).
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sorry I did only tested on digi mode :(
muhsin
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Not better, debatable. Pushing?and holding the tune knob has an existing function... The proposed function on the speed is better because it does not involve any debate!
On Mon, Nov 18, 2024 at 1:33?PM Muhsin TA1MHS via <muhsin.dogrular= [email protected]> wrote: hi
BETTER:
push the tuning knob and hold till it switches to tune mode :)
73 DE muhsin TA1MHS
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Dirk
Daniel Conklin
Todd W2TEF