Re: QMX high current consumption when input voltage above 10 Volt
Gunnar,
It is as if the feedback loop that controls the bias buck converter is not working.
Check at both sides of R505 to make sure the ADC is getting a converter output sense signal. Check at the gate of Q501 to make sure a controlling PWM signal is present.
JZ KJ4A?
On Tue, Jul 25, 2023, 7:05 AM John Zbrozek < jdzbrozek@...> wrote: Peter,
Gunnar should be able to receive at 12v without drawing excessive current. Had he wired for 12v operation, that would be mandatory. I believe he is correct in his assessment that something is amiss.
JZ KJ4A?
On Tue, Jul 25, 2023, 6:37 AM G3SPL < leepd60@...> wrote: On Mon, Jul 24, 2023 at 10:58 PM, <Ugglekatten@...> wrote:
My newly built QMX has a strange behaviour...
When supply voltage is 9V current consumption on receive is 110mA on tranmit 1.27A
Output power is fine on all bands.
I can hear signals on all bands
But when i raise supply voltage to 10.5V the current consumtion goes to 220mA, at 11V it goes to 300mAn (always in receive)
Hi Gunnar.? You say that the QMX works fine with good receive and output power when operating with 9V.? Why are you trying to run a higher voltage supply?
?
--
Peter Lee
G3SPL
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Re: QMX high current consumption when input voltage above 10 Volt
On 25/07/2023 10:37, G3SPL wrote: Why are you trying to run a higher voltage supply? Peter, That is a good question. But it does seem strange. Assuming that transmit is not attempted I'd expect the current to go down as voltage is increased due to the switched regulators on board. 73 Alan G4ZFQ
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Re: QMX USB socket not soldered?
#qmx
Mine looked like that also. Worked fine without doing anything.?
--
73, Dan? NM3A
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Re: QMX high current consumption when input voltage above 10 Volt
Peter,
Gunnar should be able to receive at 12v without drawing excessive current. Had he wired for 12v operation, that would be mandatory. I believe he is correct in his assessment that something is amiss.
JZ KJ4A?
On Tue, Jul 25, 2023, 6:37 AM G3SPL < leepd60@...> wrote: On Mon, Jul 24, 2023 at 10:58 PM, <Ugglekatten@...> wrote:
My newly built QMX has a strange behaviour...
When supply voltage is 9V current consumption on receive is 110mA on tranmit 1.27A
Output power is fine on all bands.
I can hear signals on all bands
But when i raise supply voltage to 10.5V the current consumtion goes to 220mA, at 11V it goes to 300mAn (always in receive)
Hi Gunnar.? You say that the QMX works fine with good receive and output power when operating with 9V.? Why are you trying to run a higher voltage supply?
?
--
Peter Lee
G3SPL
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Re: QMX KIT Delivered today
Mine just been delivered #72373
---------------------------------
73 de Marek SP9TKW
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Re: QMX USB socket not soldered?
#qmx
Thanks for the reassurance Hans, All my qrplabs builds have worked well up to now, I dont want to blot my copybook.?? Confidence ebbs as age and poor eyesight progress..? best regards? ? ? scotty
On Tuesday, 25 July 2023 at 11:56:20 BST, Hans Summers <hans.summers@...> wrote:
Hi Scotty
Things like this happen. Ever try manufacturing anything of anywhere near this level of complexity and you'll quickly come to understand, a thousand things can go wrong, and some actually will.?
In this case it only LOOKS like there's a problem. There's solder in the holes. Good connection. Because all the boards are tested. So you don't need to do anything, 99% sure it will work fine with no intervention. I just added that step in the manual as a precaution.?
FYI I specifically searched for this USB-C connector at Digikey for it's high-quality and the fact that it has pins not SMD pads, because I believe it will be more robust and durable. A connector with only SMD pins is much more prone to dry joints and mechanical issues. 73 Hans G0UPL
Same here , two of the mounting pins soldered, none of the other. Not sure if I have the neccessary steady hand or eyesight to remedy. Its disapointing to say the least. Scotty
On Tuesday, 25 July 2023 at 11:10:26 BST, Peter GM0EUL < gm0eul@...> wrote:
Mine looked like that too.? I just re-flowed it with plenty of flux, a big blob of solder and wicked it off.? Scrubbed it clean with isopropanol and inspected it with my loupe.?
73 Peter GM0EUL
CWops 1899. FISTS 18888, SKCC 16307T, GQRP 15056
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Re: QMX USB socket not soldered?
#qmx
Hi Scotty
Things like this happen. Ever try manufacturing anything of anywhere near this level of complexity and you'll quickly come to understand, a thousand things can go wrong, and some actually will.?
In this case it only LOOKS like there's a problem. There's solder in the holes. Good connection. Because all the boards are tested. So you don't need to do anything, 99% sure it will work fine with no intervention. I just added that step in the manual as a precaution.?
FYI I specifically searched for this USB-C connector at Digikey for it's high-quality and the fact that it has pins not SMD pads, because I believe it will be more robust and durable. A connector with only SMD pins is much more prone to dry joints and mechanical issues. 73 Hans G0UPL
Same here , two of the mounting pins soldered, none of the other. Not sure if I have the neccessary steady hand or eyesight to remedy. Its disapointing to say the least. Scotty
On Tuesday, 25 July 2023 at 11:10:26 BST, Peter GM0EUL < gm0eul@...> wrote:
Mine looked like that too.? I just re-flowed it with plenty of flux, a big blob of solder and wicked it off.? Scrubbed it clean with isopropanol and inspected it with my loupe.?
73 Peter GM0EUL
CWops 1899. FISTS 18888, SKCC 16307T, GQRP 15056
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Re: QMX USB socket not soldered?
#qmx
Same here , two of the mounting pins soldered, none of the other. Not sure if I have the neccessary steady hand or eyesight to remedy. Its disapointing to say the least. Scotty
On Tuesday, 25 July 2023 at 11:10:26 BST, Peter GM0EUL <gm0eul@...> wrote:
Mine looked like that too.? I just re-flowed it with plenty of flux, a big blob of solder and wicked it off.? Scrubbed it clean with isopropanol and inspected it with my loupe.?
73 Peter GM0EUL
CWops 1899. FISTS 18888, SKCC 16307T, GQRP 15056
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Re: QMX USB socket not soldered?
#qmx
Both of mine looked like that. I touched up one and left the other alone. Both work fine. The paste is hidden under the jack. I won¡¯t be touching up any more.?
-Mike/w1mt
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Re: QMX USB socket not soldered?
#qmx
They all look bad, like they're unsoldered. But actually they are OK. As a precaution, the assembly manual has a step about touching up the connections with some solder. But in actual fact by definition the connector is OK and electrical connection is made, since it is part of our testing during preparation of the board. But sure, it looks like too little solder on there. A bit more can't hurt.?
The next batch of 1100 PCBs are in Istanbul for customs clearance today. I did kick the PCB factory about the USB-C soldering so let's see if they're better this time! 73 Hans G0UPL
Thanks? - I shall be doing the same and not worry!
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Re: QMX high current consumption when input voltage above 10 Volt
On Mon, Jul 24, 2023 at 10:58 PM, <Ugglekatten@...> wrote:
My newly built QMX has a strange behaviour...
When supply voltage is 9V current consumption on receive is 110mA on tranmit 1.27A
Output power is fine on all bands.
I can hear signals on all bands
But when i raise supply voltage to 10.5V the current consumtion goes to 220mA, at 11V it goes to 300mAn (always in receive)
Hi Gunnar.? You say that the QMX works fine with good receive and output power when operating with 9V.? Why are you trying to run a higher voltage supply? ? -- Peter Lee G3SPL
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Re: QMX USB socket not soldered?
#qmx
Thanks? - I shall be doing the same and not worry!
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Re: QMX USB socket not soldered?
#qmx
Mine looked like that too.? I just re-flowed it with plenty of flux, a big blob of solder and wicked it off.? Scrubbed it clean with isopropanol and inspected it with my loupe.?
73 Peter GM0EUL
CWops 1899. FISTS 18888, SKCC 16307T, GQRP 15056
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QMX USB socket not soldered?
#qmx
I received my QMX today (Thanks Hans!) and am just sorting all the parts out and checking the boards over.
I know it's recommended to touch up the soldering of the USB socket, but it looks like it hasn't been flowed at all - is this normal? Happy to solder it, just interested to know.
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Re: QMX KIT Delivered today
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Hans usually answers many many questions in great detail and with seemingly stoic composure, even about shipping.
Apparently he doesn't mind.
We have been told several times that it can take longer!
While he is writing, he cannot develop! (or can he?)
Write with your left hand, solder with your right? :)
For my part, I prefer this approach:
- Patiently wait for the QMX kit.
- Head loupe, good lighting, fine hot soldering iron tip, extra screen right next to the soldering station to read and look at the assembly instructions.
- Patience when soldering
- read many things two or three times
" The way is the goal". I am really looking forward to getting this little masterpiece up and running.
By the way, I have already burnt out both transistors in the QCX 50w PA.
The reason was that I didn't look closely enough at the assembly instructions and connected transformer T1 incorrectly.
I was very surprised that Hans took the time to help me.
I had not expected it. So I also stopped him from developing.
Anyway, my QRP Labs devices are working fine.
Soldering or writing?
Kind regards, Axel
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Re: QMX arrived, built and working
Thanks Peter Glad to hear your success story and that you like it :-)
On Tue, Jul 25, 2023 at 12:48?AM Peter GM0EUL < gm0eul@...> wrote: Hi
My QMX arrived last week and I built it over the weekend.? I found it harder to build than expected!? satisfyingly challenging mainly due to high density and I was surprised at how much head was needed to properly solder the components, specially soldering to ground.? I guess that's the thick multi-layer board and big ground-planes.? I was using a good Hako soldering station, 60+W set to 400C.
I powered it up as per Hans's advice using a power supply set to 7V and limited at 250mA.? Initially it was dead!? Brief panic but I quickly traced it to a dry joint right at the ground of the main DC power socket.? Resoldered it and tried again.? This time it came to life immediately and the firmware was loaded without incident.
Receive seems fine.? Tried transmitting and got an almost immediate response from John M0STQ in Gloucester, about 300 miles, on 40m.? My QMX is built for 12v but I kept the power supply at 9V and current limit at 1A, just in case.? All seemed good and it was putting about a solid 3W.? Similar power out on all bands.? I turned it up to 12V and it was putting out just over 5 watts.
I really only want it for cw so may not explore its digital capability and it doesn't matter to me if it ever does ssb.? I love it, its everything I'd hoped for and I can't wait to take it on holiday in September.
And compliments to Hans on the engineering design to fit such a complex radio into such a tiny box.??
73
Peter, GM0EUL
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Re: QDX HB No power on 17m/15m
If as you said 20, 12 and 10 meters are operating fine, the BS170 transistors are OK and your problem is elsewhere.
A good place to look is the low pass filter for 17 and 15 meters. Quite possibly a circuit connection has gone open. Prime candidates are the enameled wires from the toroid inductors. If you have done an inadequate job of removing that enamel from the wire at the solder joint a poor and unreliable connection will be made. Possibly no connection at all!
After several good QSO's on 17m/15m - had a sudden no power on these bands after changing antenna's. 20m, 12m and 10m are still operate fine.? Should I replace Q8 & Q10 (BS170) and what should be the ma min spec got replacement BS170's?? ?
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Re: #qmx receiver optimization - what are folks getting for image rejection?
#qmx
Hello Andrew
Component tolerances, winding style of toroids, a bit of luck, can all play in... the image rejection achieved is the result of how closely the amplitude of the I and Q signals match, and how accurate the phase shift is. I don't worry about it too much because if you have anywhere around 30 or 40dB you know you basically built it correctly; and a little further down the line, I believe I can implement firmware enhancements to automatically measure and compensate for amplitude and phase errors.?
On Tue, Jul 25, 2023 at 1:47?AM Andrew < ki7fxl@...> wrote: The test sweeps in the menu are both a blessing and a curse... I obviously want to extract the best performance out of this rig that I can but I tend to get obsessed with it. I should point out that I'm not having any particular operational problem, I've had the rig on air and it has been working great so far, I'm just a little fixated on maximizing all the parameters if at all possible.
So, I built my QMX this past weekend using the latest guide, with the "new" L401 winding. I've tweaked things to where the RF sweeps are looking fairly respectable, sideband rejection seems good, but I'm running into issues with image rejection. I'm assuming that like the similar QDX that 40dB or better is basically the goal but I'm not reaching this anywhere but 20 meters:
20m: -47.1
30m: -35.9
40m: -31.3
60m: -33.2
80m: -26.4
I'm running off a bench supply set to 12.0V with a 50-ohm dummy load attached to the rig.
screenshots of all sweeps here:
I've already yanked, re-wound and re-tested T401 (the trifilar phase-splitting transformer) thinking that was the culprit, but readings did not change in any statistically significant way. I've also touched up all of the other magnet wire solder joints in the receive path (LPF toroids, L401 BPF) to make sure they are solid. What other things can I adjust to try to achieve this mythical all-band 40dB image rejection?
For comparison my low-band QDX that I built last year has all 5 bands at or exceeding 40dB image rejection, so I was surprised to see this turn out pretty different.
Thanks,
Andrew KI7FXL
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Hi Kevin
Sorry, I did not write the operating manual yet... with only 24 hours in a day I'm trying to fix several more urgent problems first.
On Tue, Jul 25, 2023 at 12:06?AM Kevin Gilot NZ1I < kevinemtid@...> wrote: Good Evening,
I am just looking to see if any progress has been made into the Testing and Operating Manual of the QMX.
I have my # 355 assembled but I am not fully Confident it is up to snuff.
I've seen some mods/ experiences in the various topics and would Appreciate having that type on information in one place.?
I'm? just trying to help alleviate all the questions Hans has to address instead of developing his Fine Product Line.
And giving some of us less skilled. less confident folks , all that good information in one place!
Thank you Hans and the Helpers,
73, Kevin NZ1I
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Marek SP9TKW
ZL1SGS
Peter GM0EUL