ChatGPT would not know about the QMX as its cut off date was the end of 2021.

For those interested, GPT4 (update from ChatGPT 3.5) now has an IQ of 150, or just below that of Einstein and Hawkin, or cleverer than
99,999% of the populalation. GPT5 is projected to have an IQ many multiples of GPT4.

I'm quite surprised so few of you seem to be using it, as it can of tremendous help in many fields. To have an AI at your fingertips on a PC or mobile device
that is many times cleverer than yourself that never tires of questions, is amazing.

Paul DJ0CU G4ADF?

Hi all,

I am just about to commence my very first QCX mini build and I just want to get the community's thoughts on what I am considering in doing for winding T1 for the 40 metre band.

I am a little concerned that if I wind 38 turns for the third secondary that it may be necessary to add more turns in the alignment steps to get it tunned. My thinking is that it will be easier to remove turns than to add, that I should consider winding 43 turns instead and have the possibility that I will have to remove turns.

So my question to the community is how common is it that constructors need to add turns to the standard 38 turn winding for S3? How common is it that turns need to be removed from the standard 38 turns?

Many thanks,
Glenn VK2AXV.? ??

Any video on QMX is a good video!
Thank you Hans, that you do this work.

( But you still have to work on your acting skills).

I had already written elsewhere. EVERYONE who proceeds normally carefully and adheres to the building instructions will have success.
I had bought a new side cutter to separate the wires just above the solder.
With the 0.6mm wires I have then applied to the fresh separation point again solder, so is in any case 100% contact.

Meanwhile, you can already see many pictures of finished soldered QMX boards, it strikes me that very often much too much solder is applied.
It is completely sufficient if the soldering eye is closed by the solder.
A solder hill over each soldering eye is not necessary.

The path is the goal! I also soldered this kit with pleasure.
The degree of prefabrication is high, you can take your time and it still goes fast.
Thanks again to Hans for putting so much work into the build documentation.

Greetings from Germany,
Axel, DL5GT

This was a challenging kit due to the density on the PCB, but the instructions were very thorough and I was able to complete it successfully. I've made a dozen or so QSOs with it and the performance is outstanding. I've been able to work stations up to 2,500 miles away. Amazing! Thank you for making this kit available.?
--
Marty Mueller, N7AAE

Dear Karl,
I went to the QDX v5 manual and the size of most of the parts in the QDX are 603.?? There is no size given for the 47uh inductors.? All it gives is the inductance value and SMD.

so, I really don't know what the size is.?? maybe you can get an idea from the picture.?? I wish I still had the two hanger queens of broken ones that some of the guys here brought

for me to fix.?? Then the job would have been easy.?? I would have taken one of the 5 47uh SMD inductors out and put it in place of my broken one.

Take care and have fun.
73 Dave WA5DJJ

"anything worth doing isn't always EASY!"

4. Replacing the 5V board, what is the resistance to ground on the?left side of D108 (towards the audio board)

Towards the audio connectors, I meant.

Please make sure you've disconnected the radio from power when checking the resistances.

Jonathan KN6LFB

Stephan Ahonen KE0WVA <stephan.ahonen@...> wrote:

you will need a hot, powerful iron with plenty of thermal mass to make
good joints in them.

This is a good advice. My 40 W soldering station was too weak (even with
the slightly larger tip than I usually use) and I had to use my stronger
(100 W) transformer gun for some joints.

Hans recommends 60 W iron and I think it should be fine.

enamel on the thinner magnet wire used for filter toroids burns off just
fine but the thicker magnet wire used for power magnetics will need to
be sanded off.

I just used a knife.

I suspect a partial/resistive short from one of the power rails to ground.

1. Can you provide photos of the bottom of the main board and the bottom of the power supply boards?
2. If you remove power, what resistance to ground do you have in the following locations on the 3v3 board:
? ?a. The rightmost pin of the board connector?
? ?b. The side of D103 closest to IC101 (away from the connector)
3. Do any of these resistances change if you remove the 5V board?
4. Replacing the 5V board, what is the resistance to ground on the?left side of D108 (towards the audio board)

Jonathan KN6LFB

Dear Karl,
I think all the SMD parts in the QDX are 605 size or something like that.? It is real tiny.? My cheapie caliper said the length of it was 1/16th of an inch.?

Here is a picture of a group of the parts including the L11:

The picture is from another circuit board that has a good L11 on it.

hope this helps.??
73 Dave WA5DJJ.

Hans Summers <hans.summers@...> wrote:

2) You also need to remember that all mailing lists have an inherent
negative bias, in so far as people are far more likely to post about a
problem they are looking for help solving, than they are when everything is
fine.

This is true. Let me tell you that I already managed to make some contacts
with the new QMX. I just don't post, because it works :)

Firmware still has some bugs (both in UX and in CAT control), but basic
functionality works, so I'm happy and (although after only a copule of
days) I don't regret buying QMX.

My only concern is if I wound the SWR transformer correctly, but if I
didn't, then I guess I'll find out after you add support for SWR in the
firmware.

5) If you take care and observe all the precautions mentioned, there is a
VERY high probability of success. Remember, component and manufacturing
failures are rare. It's largely in your hands!

True. QMX is very tightly packed, maybe even too tightly, but I didn't
observe any manufacturing failures. I must've been lucky.

Steve MW0KST <stevedavies77@...> wrote:

Sorry folks - found the short - yes, it was at the BNC socket.

Great to know you fixed it :)

In my case the short was exactly at the BNC socket. There's a footprint
for the SMA socket there as well, and I had a short between one of BNC
grounding pins and the unpopulated SMA center pin.

Here, in blue:

Thanks Ron,??
Will give that a try.? I'm gonna be back in SFO in 2 weeks and will give a try again then.?

On 31 Aug 2023 at 18:29, Mike KK7ER wrote:

QMX transceivers are commonly used in amateur radio, public safety
communications, and commercial applications. They are also used in
some military applications.

No wonder Hans cannot keep up with the production
demand ... with every soldier and sailor having a QMX
in their pocket, they will be like HF pocket phones. LOL

It is doubtful the board is getting hot.? Easy to put a probe onto a convenient location.? Many DVMs come with temperature probes.? (I would consider less than 40C as warm)

I have not tried ChatGPT but here is what Google Bard has to say about the QMX:

Me:
Bard:??

Thank you so much for your interest in my problem (s).

I think I have more than one problem. The unit won't shut down by pressing left encoder. I have checked and rejected the encoder connections to the board and have made sure they are not electrically touching the encoder body. With probes connected to pins 2&4 of the six pin header and pressing the left encoder, I get a buzz on my multimeter (continuity). ?I reflowed the 6 pin header on control board and now they is a mess of burnt roisin. I can measure continuity from the pins on control board to the main PCB connections on the bottom. I most definitely have an issue. I am not sure which pins are which on the female header on the main PCB so I could short them temporarily in hopes of getting the unit to shut down. If I can, then I my shut down problem is on the control board.


On to voltages on the PS boards.

If I set my bench supply to 8v, 225ma, I get the following. (When on, voltage drops to 5.25 and 223ma)

? ? ? ? ? ? ? ? ? ? ? ? ?ENCODER OFF ? ? ? ? ? ? ?ENCODER ON
5v board
Q103 Gate ? ? ? ? ? ? ? ? 7.92 ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0.0?
Q103 Source ? ? ? ? ? ? ?7.69 ? ? ? ? ? ? ? ? ? ? ? ? ? ?5.1
Q105 Gate ? ? ? ? ? ? ? ? ?7.92 ? ? ? ? ? ? ? ? ? ? ? ? ? ?0.0
Q105 Source ? ? ? ? ? ? ?7.69 ? ? ? ? ? ? ? ? ? ? ? ? ? ? 5.14

3 v board
IC 101 G ? ? ? ? ? ? ? ? ? ? 0.0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0.0
IC 101 S ? ? ? ? ? ? ? ? ? ? ?4.7 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 3.2

Measuring the headers of the 5v board:
OFF
1=7.93 (leftmost) ? ? 2=0.0 ? ?3=8.0 ? ? ?4=0
ON
1=5.25 ? ? ? ? ? ? ? ? ? ?2=1.26 ? ?3=5.28 ? ?4=2.375

3v board:
OFF
1=0 ?(leftmost) ? 2=0 ? ? ? 3=0
ON
1=0 ? ? ? ? ? ? ? ? ? ? 2=5.08 ?3=5.1

D103 ? 2.426 when unit on instead of -3.3V ?as you suggested.
Grounding the 78M33 (middle pin) turns the unit off

I am confused and do not know what should be my next step. I keep doing the same thing over and over and getting the same results which is the definition of insanity. I hate to give up, but I am stumped.

Thanks for your thoughts
Phil

What size is this SMD 47μh choke?
--
73
Karl
KI4ZUQ

开云体育

All my co-workers were issued 1740 or 1741A scopes. I was working on higher frequency stuff, so I lucked out with a 275Mhz 1726A scope..with the LED display riding on top. Loved that scope, and was able to keep it after I left HP/Agilent...but time marches on, and scopes got smaller. Sold it for a much smaller Tektronix scope a few years ago!

....Dave