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Re: My new QMX+ #QMXplus

 

Agreed.? I think making a option for say 160-20 of 40-10m or 6m would be nice.? Then maybe ea. filter only has to cover 2 bands
?
Mark N5MF
Re: My new QMX+ #QMXplus

 

Mark,
?I have had the same problem trying to get 20, 17, & 15 m to peak up in power. Whenever you get one band up, the others are down. I don't think there's a good solution, but it's well under 1/2 S unit down, so I don't think it's a big problem. Be nice if there was an extra LPF so you only have to get 2 bands with each LPF.?
--
73, Dan? NM3A
No special characters to delete messages?

 

Hello Everyone,
?
I just fired up my QMX with Firmware version 1.00_025 and tried to edit the message memory.
?
Adding characters works fine (via tune nob as well as vis CW keyer). However, while using the tune nob I can't see any of the special characters (Insert, Backspace, Delete. etc.).
?
Is there some hidden option in the menu to enable them?
?
Thanks and 73
?
Chris
PY2GUT?
QMX SMPS issues, and a possible cure

 

I'd like to know the firmware and hardware rev from anybody who has trouble with the QMX 3.3 and 5.0v power supplies.
Mostly, I'd like to know how often these failures occur with the most recent firmware and hardware.
If that gets noted here in the forum, the pressure increases to find a more robust solution.
?
Symptoms might be a bad diode at D108 or D109, a fried processor, fails to work after jiggling the power connector,
fails to work after accidentally shorting a power supply with a probe, fails to work after multiple short power button presses.
?
As I previously reported, I have some linear regulators on a one inch square scrap of vector board that plugs into JP105,
this seems to work well after some minor mods to the QMX.? Specifically, need to lift the drain lead of Q106 and Q107 to
disable the old SMPS's, need to add 200k in parallel with R112 and R113 so the firmware thinks it's seeing a bit more than
3.3v and 5v (it hangs if it sees a wee bit less) and short drain to source across Q111 so the 3.3v linear can drive ADC_3V3.
?
I'd prefer that Hans change the firmware such that at power up it first checks if LIN_REG_EN is low, and if so skips all the
SMPS start up and voltage checks.? Then the only mod to the QMX would be to add a 10k resistor from LIN_REG_EN to ground.
?
I don't encourage others to repeat my efforts at this time unless this is simply something you enjoy doing.
Odds of blowing up your QMX are greater with my mods and hacks than they are with the old SMPS's.
Success is not guaranteed.? Reports of SMPS failures are no longer very frequent with Hans' latest firmware,
especially given that there are?thousands of QMX's in operation.??
?
As Hans has said, there are many different kinds of failures being reported in the forum.? The majority are due
to bad soldering, especially around attempts to burn the enamel off of the magnet wire.? Fortunately, most?
failures are easy to repair.? Unfortunately, an SMPS failure often blows the 100 pin STM32F446 processor.
?
I feel that the primary issue with the old SMPS's is that the voltage gets checked by the processor only once
every millisecond or so.? That's fine if everything works as it normally does, but something unusual can?
upset things faster than the processor can react.? For example, if the 5v rail is momentarily shorted to ground
by a scope probe, the processor might increase current to maintain 5.0v but not react fast enough when the
short goes away.? Designing an SMPS from scratch (or in firmware) is a difficult exercise in control system theory.
?
I just received my Kicad PCB fab for a one inch square board to replace my linear regulator vector board.
This design has a couple SOT23-6 SMPS IC's.? There's a huge number of different parts from different venders to choose from.
Max current varies from 500ma to 2A. They operate at frequencies varying from 0.5 MHz to 2.2 Mhz.? Cost can be as little at $0.10.
Provision is made to allow the board to be fully shielded using cheap copper foil, held up by L shaped header pins.
I am designing for the cheapest SMPS IC's which operate at an internally determined frequency, more expensive part
(still under $1) can be driven by an external clock source such as a processor PWM pin to eliminate any birdies.
The board can be separately built and fully checked out, including how it behaves with an intermittent or varying Vin, momentarily
shorted outputs, momentary low current demand, and changes in temperature.? It could be temporarily plugged into header pins
at JP105 of the QMX, or permanently soldered in place to those header pins.? If plugged in, I would recommend adding a
soldered wire connection for ground, since if that flakes out momentarily it could be disastrous for the QMX. ?
If it's successful, perhaps we of the forum can make it available as a kit.?
Or perhaps Hans would like to add it to his shop for purchase.
?
Jerry, KE7ER
?
?
I started this thread in response to this post ?/g/QRPLabs/message/139515
?
Re: QMX+ shutdown problem
On Sat, Feb 22, 2025 at 04:10 AM, Kevin (KQ4DTX) wrote:

Jerry, if your question was at me:? My QMX+ is Board V2 with firmware 1-00-027 when my occurrence happened less than a month ago.
?
Re: My new QMX+ #QMXplus

 

Here is my post for reference?
?
Mel.M0KMD
Re: Handheld QMX?

 

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And here I always thought those dual gate FETs were 40673’s. ?Ahh, the good old days when parts were visible and the part numbers could be read by the unaided eye.

Dave

On Feb 22, 2025, at 10:38, bill K7WXW via groups.io <K7WXW@...> wrote:

?
I don’t know, Jerry, maybe not the norm, but a significant proportion of hams built their own gear back then. “Solid state design for the radio amateur” sold more than 50,000 copies, the ARRL handbook was filled with practical projects and a reasonable amount of electronic and RF theory, and there were still lots of local places to buy parts. I was a digital design engineer in those days, and did RF stuff when I got tired of zeros and ones.
?
Or maybe my nostalgia for the golden years of DIY PCBs, ECL and 40763s, leaded components, and deadbugging continue to get the better of me. :)
?
bill K7WXW
Re: My new QMX+ #QMXplus

 

Ok thanks.? I figured as much.? Not a big deal but it is curious.
?
Mark
Re: My new QMX+ #QMXplus

 

Hey Mark,
?
Congratulations on your successful build!
My QMX+ also produced very silimlar output. Yours being slightly better results.
I built mine for 9v and posted my results a few days back. The general consensus seems to be that those are typical expected values.
?
Cheers?
?
Mel. M0KMD.
Re: Testing for a dead QMX board

 

2nd Jeff Moore can fix this!
Re: Handheld QMX?

 

I don’t know, Jerry, maybe not the norm, but a significant proportion of hams built their own gear back then. “Solid state design for the radio amateur” sold more than 50,000 copies, the ARRL handbook was filled with practical projects and a reasonable amount of electronic and RF theory, and there were still lots of local places to buy parts. I was a digital design engineer in those days, and did RF stuff when I got tired of zeros and ones.
?
Or maybe my nostalgia for the golden years of DIY PCBs, ECL and 40763s, leaded components, and deadbugging continue to get the better of me. :)
?
bill K7WXW
Re: My best practice for part inventory

 

Great idea using the foam board.

I do something similar when winding toroids in that I lightly tape them down with some painters tape on a stiff piece of a manila file folder. I write the particulars of the part identifier and turns next to each one. I wind all the toroids and transformers in one or two sessions checking turns and evenly spacing by eye.?

Then I test fit before removing the enamel, clip the leads about 1.5cm long from the bottom before removing them from the PCB to? remove the enamel using the 'drag through a solder blob technique' and then complete the installs.?

Zero toroid problems on 5 Qs and 3 50W amp builds so far.?

GREG


On Sat, Feb 22, 2025 at 9:23 AM, Spencer Barrett via groups.io
<Spencerbarrett@...> wrote:

YEA - just finished QMX and all diag look good - nice to have itt work 1st time - all that triple checking paid off.
BUT:
  • ?had current limit too low - so it would not stay booted
  • My 1st USB cable did not enumerate as flash drive.. 2nd cable worked

Was very valuable to visual inventory and pre-sort all caps w/ a printout on foam for parts/Part#

AND - I am 60 years old.. so all work was done under a MAG LIGHT




--
---------------------------------------
KINETIC LABS
14850 NW Northumbria Lane
Beaverton Oregon 97006
FAX: (413) 294-7223
PHONE: (503) 382-7117
spencerbarrett@...
My best practice for part inventory

 


YEA - just finished QMX and all diag look good - nice to have itt work 1st time - all that triple checking paid off.
BUT:
  • ?had current limit too low - so it would not stay booted
  • My 1st USB cable did not enumerate as flash drive.. 2nd cable worked

Was very valuable to visual inventory and pre-sort all caps w/ a printout on foam for parts/Part#

AND - I am 60 years old.. so all work was done under a MAG LIGHT




--
---------------------------------------
KINETIC LABS
14850 NW Northumbria Lane
Beaverton Oregon 97006
FAX: (413) 294-7223
PHONE: (503) 382-7117
spencerbarrett@...
My new QMX+ #QMXplus

 

Just wanted to say that the QMX+ was a pleasure to build and, now that I've actually read the operations manual, it seems to be working as advertised!? With the GPS finally syncing up.
?
My power is pretty typical I guess but I am a bit surprised that the the 20 and 17 are so much less than the 15 meter output.? Built for 12V
?
160? -? ?5.6
80? ? -? ?5.6
60? ? -? ?4.8
40? ? -? ?4.8
30? ? -? ?5.0
20? ? -? ?3.8
17? ? ?-? 3.0
15? ? ?-? 5.2
12? ? ?-? 3.1
10? ? ?-? 3.8
6? ? ? ?-? 2.5
?
Everything seems to be as advertised with no issues when following instructions.? HI
?
If any one has found a way to get 20 and 17 up a bit i would be interested.? seems they should be as good as 30 and 15!
?
Anyway very nice project.? Hats off to Hans for another fun radio.
?
?
Mark N5MF
Re: Toroid Winding Quality #building #QMXp #QMXplus #toroid

 

I wound the torid in tight groups of 6x - Note the 27 turn fills up the inside of the torid.
- When I verify the groups fo 6x.. it is not easy to count - but I find the middle of the 6x winding - and there are three windings to left and right.

?- Spencer

On Sat, Feb 22, 2025 at 3:54?AM David Wilcox K8WPE via <Djwilcox01=[email protected]> wrote:
Just take a photo with your smart phone, enlarge it, count the turns easily then. ?

Dave K8WPE

PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!





On Feb 21, 2025, at 10:28?AM, Larry- WA2VKG via <lbakely=[email protected]> wrote:

?
Dave- LOL.? Yeah, it is actually kind of relaxing to wind these things. But the counting does stress my poor little brain....
Thanks for the encouragement.



--
---------------------------------------
KINETIC LABS
14850 NW Northumbria Lane
Beaverton Oregon 97006
FAX: (413) 294-7223
PHONE: (503) 382-7117
spencerbarrett@...
Re: QMX+ shutdown problem #qmx #QMXplus #shutdown

 

I GIVE UP!
?
Pressing the encoder the +12V pad showed 11,5V, Vdd 0,01V and Vcc 1,15 V.
But then, possibly the DMM probe shorted the Vcc and Vdd pads of JP105...
Every voltage is now zero, the encoder pressed or not.
?
I really would like to see a robust QMX++ with linear regulators. So much trouble (me and many many others) with the SMPS'es.
Remember the KISS principle!
Saving some hundred mA may be relevant if running with alkaline batteries, but most of us are using AC powered chargers or massive lithium batteries.
?
--
73 Matti OH6BEX
Re: QMX+ shutdown problem #qmx #QMXplus #shutdown

 

@ Jerry Gaffke,
?
? Jerry, if your question was at me:? My QMX+ is Board V2 with firmware 1-00-027 when my occurrence happened less than a month ago.
?
@ Mattie
?I see you checked your unit with 12.15 voltage applied.? ?Your results were no voltage at VDD and VCC when referenced with ground.? ?Please understand that these points are after transistor(s) that would kick in (switch on) after the Processer or Voltage Regulator circuit is satisfied with certain conditions.? ?Your unit is not meting those conditions.
?
I suggested earlier that you check the Resistance with your ohm meter across VDD and Ground to see what the readings are.? This will let you/ us know if you have some damage part(s) on the 3.3v rail.? As I said earlier that mine had a reading around 260ish ohm (No Good) on that rail.? That told me that I needed to go down that rabbit hole looking for an issue there.? ?Mine ended up being that D109 was damaged and pulling the voltage to ground.? This didn't let the 3.3v power get to the proper voltage to power the circuits needing that power rail i.e., the brains of the unit, the processor.? ? If you choose to, please look at my earlier post and share your findings with what you get on checking the resistance across VDD and Ground. THIS IS WITH NO VOLTAGE APPLIED TO THE QMX+.? ?I just opened up my unit and confirmed that my resistance reading taking from JP105 VDD to ground is 2.54 K Ohms on the working unit.? Let us know the results.
?
?If your results with the ohm reading is not above 1k ohms, I would then try testing the unit like I said in the earlier post.? ?Apply power (If you can put your unit on a regulated power supply with 7V, 250m amp limit setting).? Place a finger on the Q109 or Q111 (my version 2 QMX+ these were found on the bottom of the main board).? While holding down the Power Button, did the transistor get hot to the touch?? If the answer is yes than something is pulling too much current and not allowing the supply rail to get to 3.3 volts.? for me, the diode had shorted and cause the issue of pulling too much current to ground (D109).
?
?I just trying to help so if you could post the results of your findings this could help the group understand what your next steps is/ are.
?
73 KQ4DTX
Re: Toroid Winding Quality #building #QMXp #QMXplus #toroid

 

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Just take a photo with your smart phone, enlarge it, count the turns easily then. ?

Dave K8WPE

PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!





On Feb 21, 2025, at 10:28?AM, Larry- WA2VKG via groups.io <lbakely@...> wrote:

?
Dave- LOL.? Yeah, it is actually kind of relaxing to wind these things. But the counting does stress my poor little brain....
Thanks for the encouragement.
Re: Handheld QMX?

 

N6ARA is working on a tiny-tunable-antenna (based on the "" design antenna that seems popular in...Asia) that can go directly on small QRP rigs. https://www.instagram.com/p/DD5xJzuPVHj/?img_index=1
?
This may be a winner for super fast and light field use with the QMX - frankly, any QRP radio.
?
Also note tiny paddle at bottom plugged right into key port - he’s built a poor-man’s KH1.
?
Re: Handheld QMX?

 

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Yoon, I have had some RF feedback using my KH1 at times in certain circumstances. ?It was usually on my deck in a stucco sided 3rd floor condo here in Florida. ?I was using my SuperAntenna MP-1 fastened to the deck railing. ?I then put a CMC out 10’ in the feedline and that solved the problem.?

Dave K8WPE

PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!





On Feb 21, 2025, at 4:08?PM, Yoon KM6KJI via groups.io <yoonh.choi@...> wrote:

?
On Fri, Feb 21, 2025 at 11:49 AM, Wei AG6AQ wrote:
I was inspired by your post and tried myself with MFJ1720, the major problem is RFI. Have you seen RFI problem in your handheld setting?
Wei, what was the symptom of the RFI problem? Maybe some erratic behaviors of QMX like turning off itself or the keyer suddenly not working, etc.?
?
I do remember having that kind of problems when trying handheld operation with different whip antennas and certain lengths of counterpoise wire. I think the problem can be generally minimized with the lowest SWR you can achieve, although there are many other factors affecting the antenna match with HT operation - your hand, head, body and your posture, also the dry or wet ground where you stand on, etc.
?
Then I found it very handy to use the reel wire as the counterpoise, with which you can easily find the best match in any circumstances, which will surely minimize the RFI problem. I haven't had the problem with my whip antenna and the reel counterpoise wire.
?
73,
Yoon KM6KJI
?
?
Re: Handheld QMX?

 

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Yoon,

Where did you get that neat key in this photo?


A friend of mine gave me one just like it yesterday at breakfast. He thought it was a prototype as it was included as a freebie when he ordered a cap/resistance measuring device from Denmark. He uses big manly keys so had no use for it. Ha! ?I am finding that it has a nice feel and will no doubt use it with some of my QRP rigs.?

Dave (Djwilcox01 at gmail)

Dave K8WPE

PS ?Now I understand…… He who dies with the most toys has probably forgotten much what he has and why……. So true!





On Feb 21, 2025, at 2:32?PM, Yoon KM6KJI via groups.io <yoonh.choi@...> wrote:

?
It seems any photos attached to a thread are gone after a couple of weeks? So instead of posting my handheld QMX photos here again, I recommend you to visit my QRZ page to see how I'm operating QMX as HT -
?
I have integrated it with the battery (3s1p 14500 li-ion cells with BMS), the internal speaker (though not much useful for noisy outdoor), and the plugin single lever cw paddle. For the whip antenna and the reel counterpoise wire combined with the QMX's built-in SWR bridge, I don't need an ATU.
?
73,
Yoon KM6KJI
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