Re: Here's what QSOs look like from the W4MAI ( SK 2006 ) Memorial Sun room monitoring station.
I just love it when the entire QSO is displayed on the combination Malachite Malahit having a ~ 14-inch whip and Dell i3 PC !
72,
Bill, N4QA
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Main microprocessor failure
#qmx
Hans,
Where can I find a replacement microcontroller for the QMX? Mine has a dead short internally.
S/N 331 has been functioning nominally now without issues (except for those noted BPF and CW issues). I usually operate it from fused 8 volts and always good impedance match so no strains. Was working properly when I shut it down in the afternoon. Following morning I placed it on the test bench prior to testing CW keying. Applied 8 volts from the bench supply, current limited to 800 ma. When I pressed the left encoder switch to power it on the current jumped to 600 ma. for about half a second and then dropped. Nothing else happened.
Disassembly and test revealed VDD shorted to ground with less than 3 ohms. Using a Siglent SDM3045x DMM (which has 2W resistance resolution to .01 ohm) I carefully traced the low resistance to the microprocessor VDD inputs. It was quite tedious without Gerber files to be able to trace those "underground" tracks.
Under the microscope I carefully unsoldered each VDD pin, raising it above the pad, until I raised pin 19 (VDD2) which cleared the VDD bus. All of the VDD pins except for VDDA seem to be shorted to ground.
I am unable to determine a cause. Everything is in place and solid (I am a very careful builder. Slow but careful) and nothing has been intermittent. I wouldn't think that it could have been over-voltaged since D109 is in place (but I have not removed it for test). Nothing was attached at the time of failure except the power and a dummy load. Power was supplied by a Siglent SPD3303x-e which I have found to be very reliable. The DMM is very gentle, and applies only 0.65 volts to the probes and I have never experienced a problem caused by it.
I am not sure of the nomenclature of the chip since it is covered by a waxy coating. Your FDIM presentation mentioned a STM32F446VET6. Could this be it? Is it ordered with any special programming?
I may delay further work until a year has passed. It has been a time consuming project up until now and I should probably wait until the dust settles before devoting much more effort. Other projects are calling.
73, Don
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QDX Terminal Emulator - problem editing values
In terminal emulator mode on a serial port, I am unable to edit certain numeric fields using delete or backspace. Specifically audio gain value under band configuration menu that is default to 54.
QDX HB Rev 5 with v1_10 firmware. Running MobaXterm on Windows 10 PRO.?
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Re: QCX Birthday - 20,000 sales coming up!
Hans,
20,000 !! QCX series ordered (to date). Outstanding piece of work to you and your crew.?
73 Kees K5BCQ
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Re: QMX unboxing and a couple of surprises
Mine arrived today - box was damaged a bit by customs/courier. All content in tact. Boards solid in one piece and no missing/broken elements (at least didn't found them at initial inspection).
BTW it was record delivery time :
- Collection 4 days (including Sunday)
- Grezimir to Dublin 19h (yes 19hours !!!- still cant believe as last time was about a week)
- Customs/local TNT depot? 1.5 day
Thank you Hans - looks they finally taking it seriously (at least outside of Ireland :D )
73 de Robert EI9ILB
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Re: QMX unboxing and a couple of surprises
2nd QMX arrived Monday. My PCBs were split too. Package did not look as if it was damaged. Have not checked out the rest of the contents.?
--
73, Dan? NM3A
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Re: 50W amplifier - 13.8V power supply
I have one of these $20.00 Amazon converters and it has wandering noise spikes that blot out strong shortwave signals as the spikes wander by slowly, usually down freq. Now, was gifted a switching supply from MFJ that is electrically silent but has noisy cooling fans!
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Re: 50W amplifier - 13.8V power supply
John,
How does the ripple look during large current draw when the TX is key'd up?
Unfortunately, I do not have a working o'scope, so I can't speak for what the output looks like during use :-( Regards, Charles Johnson KF4AYT
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Re: QMX C218 Replacment Part from Digikey?
I just did a quick search on Amazon and found these ...
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Re: QMX unboxing and a couple of surprises
Hans,
Thanks for your prompt reply. I¡¯d already ordered some 47nF capacitors so I¡¯ll probably fit them, but it¡¯s nice to know that they aren¡¯t critical.
73
John
G4YTJ
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Re: QMX unboxing and a couple of surprises
Hello John
The first thing I did was to check off all components against the parts list. There were two knobs in a separate bag and another two in the main packaging, so I¡¯m two knobs up! The knobs all appear to be the same size.
Bonus for you! Kick for my colleagues...??
I then removed the PCBs from their anti static bag and immediately photographed them. The LCD board was broken off from the main board - I¡¯m not sure if that¡¯s to fit them in the bag or whether it got damaged in transit.
That's not how we pack them, we pack them in one piece. Not broken apart. So this must be a transit thing. Nevertheless it's the first time I have heard of this so I think it's not common, and in any case the first thing you are going to do is break the boards apart so it should not matter.??
Looking at the photos I saw that C205 and C210 had broken off the main board. Coincidentally one of them appeared in one of the other photos, and I found them both on the tray.
C210 is a 100nF decoupling capacitor and might not be critical, but C205 (47nF) is on the processor reset line and might be essential.
Neither of these capacitors are critical. I believe the 47nF on the reset line is only required during Flash programming of the bootloader. Once done, it is not a requirement. The other decoupling capacitor as you say, is a prudence (follow all datasheet recommendations on capacitors everywhere) but it should still work without it.?? I¡¯m quite happy to resolder the capacitors but neither of them check out with their correct value (my DVM has a capacitance range, I checked some through hole capacitors to confirm that it was working).
I wouldn't worry about that either. I don't use expensive precision capacitors for the capacitor positions where it is not critical. The expensive capacitors go in the LPFs and BPFs.?? My suspicion is that the capacitors got knocked off by the LCD board in transit, which is why they were in the packaging.
I suspect you are right? Hans, if the boards are supposed to be separated, can I suggest something like a piece of card slipped between the two to prevent the capacitors from being knocked off?
The PCBs aren't supposed to be in two parts...? If I order some replacement capacitors, I¡¯m thinking of substituting 47nF for C210 so I¡¯ve only got to order a couple of the same value.
I would just use the supplied ones. Or not bother...?? Any comments/suggestions gratefully received.
?I'm sorry to hear about the mishaps but I think these are non-critical things, that won't affect anything about the build outcome - so I'd just proceed regardless...
73 Hans G0UPL
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Re: QCX Birthday - 20,000 sales coming up!
Here is a 2017 tooling up for the 2023 es 2024 solar eclips
Check out my QRZ page
...Copied from bowels of this old tablet ...
...(2017dec31 ... QCX 80, 40, 20 ... sn 1166, 7, 8 ...arrived 2017nov25)
HAPPY BIRTHDAY es many MANY more
72 73
John
N3AAZ
FM19 on DELMARVA Peninsula
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Re: QMX unboxing and a couple of surprises
John, my boards arrived as one and my first job was to separate them and smooth all the edges. Today I will check for missing parts or poor soldering. If time permits might start assembling.
---------------------------------
73 de Marek SP9TKW
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Re: QMX: Processor not booting / row of bricks
...And the solution is: I still had capacitor C403 in the circuit (might be an idea to add that to the sensitivity mod). After removing C403, the sweeps look great:
(The only mystery now remains the power board...)
73!
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Re: QDX HB No power on 17m/15m
OK Scott! Glad to help...JZ
Thank you John Z.? Back up with power by reheating all the connections associated with the 17m/15m toroid inductors.
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Re: QCX Birthday - 20,000 sales coming up!
Hi Hans
This is?Guiness book of record stuff.?
You've single handedly changed the lives of many people including myself. I would never have found my way back into amateur radio and learned so much without that first classic QCX.?
Chapeau and 73s
Ted?
2E0THH?
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Re: QMX arrived, built and working
Thanks for the nice feedback Peter
Yes, filtering will come - when other more urgent things are taken care of. I do plan to have a number of filters with different bandwidths and center frequencies; and also provision for an operator to define his own filters.?
On Wed, Jul 26, 2023 at 2:46?AM Peter GM0EUL < gm0eul@...> wrote: Hi
I just had another session with my new QMX and loving it more and more.? I've decided it is the only radio I need to take on holiday.? I'm normally torn between both QCXs, but I've made a two bander covering 40 and 20 m so I could reduce it to one.? MCHF- it feels a bit fragile and draws a lot of current, eats my battery pack in less than an hour so realistically you need to carry a spare battery and I haven't got one.? KX3- a bit heavy and I worry about the cost of anything happening to it, its advantage is it is one of the best cw radios in the world and it lasts for ages and ages on its internal batteries.? I normally end up taking my KX3 and so far I haven't lost or damaged it, but I worry.? It is a good benchmark against which to judge other radios though.??
Within the limitations of what I want a radio to do, the QMX does probably 90% of what the KX3 can do.? The extra 10% is for competition or serious dx and to be honest I don't do much of that, particularly on holiday!? Its mostly to do with receiver sensitivity, crystal roofing filters and a vast array of DSP options and electronic filtering that enables a KX3 to pull out a barely detectable signal even with a kw transmitter contesting on the same band in the next room.? I probably miss out on some of its performance anyway because I don't know what all the controls do or how to use them.
The QMX CW filtering is fine, its a good compromise, its wide and shallow enough that you can easily tune the band and hear what's there yet is narrow and steep enough to have a QSO on a reasonably busy band without being distracted by qrm.? I'd like some control over it to adjust between 100 and 1000 Hz and to offset the centre frequency to skew the shape of the filter.? I like a fairly wide filter and only close it or manipulate it when I need to.? Filtering on the QMX should be a firmware thing and it may eventually come, but I don't mind if it stays as it is now, its perfectly good enough.? ?
I was using my 12v battery pack this evening so it was putting out about 5 watts or fractionally over on 40m.? It survived a three or four second burst of auto ATU (Elecraft T1)? and I could hear signals from UK, Ireland, France, Spain.? I never had to call CQ but just answered calls, everyone I called heard me and I was getting good signal reports.? I also had an email follow up from one op commenting on how nice the QMX sounded.? All contacts made so far have been qrp/qrp and in England, Ireland and Spain.? After three back to back cw qso's over about half an hour it was warm to the touch but no more.
So I'll take my QMX on holiday, I'll leave my KX3 at home and I don't think I'll miss it.??
Brilliant radio, thanks Hans!
73/72 all?
Peter?
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Re: QCX Birthday - 20,000 sales coming up!
That's it!?
The 20,000'th QCX-series was ordered?overnight, a 20m QCX+ ordered by James Harmuth, USA.?
Bring your umbrella, boots and Skeeter stuff too.
John KK4ITX? ?Each mistake is a learning opportunity.? On Jul 21, 2023, at 5:30 PM, Mark WO7T <wo7t@...> wrote:
?Well Done Hans!!!!!!
72
Mark
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Re: Another QDX went up in smoke
A very cheap solution, like the one proposed by Chuck:?
In tuning position the SWR is always under 2:1 and in operate position this tuning indicator is by-passed. I even use it with my Alexloop, a magnetic loop, the worst danger for a QDX!
73
Pierre
FK8IH
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Re: QDX HB No power on 17m/15m
Thank you John Z.? Back up with power by reheating all the connections associated with the 17m/15m toroid inductors.
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Don, ND6T
Scott Tillotson
EI9ILB
Karl
Marek SP9TKW
Ted 2E0THH
Pierre - FK8IH