UPDATE: ?I replaced the transmit / receive switch Q6 and the ?rig is operating normally again.?

Jerry
N6JH

Billy,

Have you downloaded, printed, punched three holes and put in binder yet? No? Well, don't! I did when I first ordered the radio and built it WRONG!

Do print the most recent build instructions when you actually get the kit. Then print the operating instructions when you finish and know it works.

This? is the most challenging an satisfying kit I ever built. It has the best instructions I have ever seen. These are pretty tall observations after experiencing Heathkits in the 50's and 70's and the Elecraft K2.

I have no idea how Hans keeps up? with his creations and remains accessible to all of? us but he does, somehow. This appears to be the most active forum anywhere on the internet. Welcome to the zoo!
--
73
Karl
KI4ZUQ

Hi All,

I hope you can help me to track down problem which I have with my BPF on newly build QMX. QMX is working ok and it is transmitting 3.5-4W at 9V, I also made QSO on 40m band.

Issue I have is that I can hear only strong stations where signal on my other rig is S8 or more.

Looking at my BPF plots at terminal I can see that I have big suppression on the bands from -30db to -50dB. I think this explains why my QMX has low sensivity.

I cheked capacitors C401-404 values and location, as well as resoldered coil L401

Here are key graphs and some photos of the board.

Any pointers would be greatly appreciared.



---------------------------------
73 de Marek SP9TKW

Thank you very much for your advice. I was able to find the error. It was a short circuit on the encoder. I had finished the kit last night and wanted to get started quickly. But as Hans said in his last Youtube video - take your time, take it easy, don't be in a hurry. Then it will work :-)

73 Marcel DM3FAM

Hi Evan, no prob’s we are all human :-)

?

Looking at C27 on transmit I noticed that my oscilloscope was reporting 5v whereas my multimeter was showing 50v! All the readings below are with the multimeter including a re-done D1-6 cat.

Q3, Q4 and Q5 all look identical with SA printed on them

X6, I did notice that it’s labelled LPF _0 1 2, which I assume correspond to LPF 1 2 3, that tickled my OCD :-) I’ve used the PCB labelling below.

?

?

X6 (multimeter)	80		40		20
?	RX	TX	RX	TX	RX	TX
_0	3.2v	3.2v	0	0	0	0
1	0	0	3.2v	3.2v	0	0
2	0	0	0	0	3.2v	3.2v
?	?	?	?	?	?	?
?	?	?	?	?	?	?
C27 (multimeter)	80		40		20
?	RX	TX	RX	TX	RX	TX
?	Vs	46v	Vs	50v	Vs	50v
?	?	?	?	?	?	?
?	?	?	?	?	?	?
?	80		40		20
Diode cat (multimeter)	RX	TX	RX	TX	RX	TX
D1	0	0	5.7v	32.7v	5.8v	34.6v
D2	5.7v	32v	0	2.7v	5.8v	34.7v
D3	5.7v	32v	5.7v	32.7v	0	0.3v
D4	0	1.3v	5.7v	32.8v	5.8v	34.6v
D5	5.7v	32v	0	92.8	5.8v	34.6v
D6	5.7v	32v	5.7v	32.8v	0	75.4v

?

?

Chris

73 de M0IDE

开云体育

ps/ps
that is (hamSCI.org)
n3aaz

?Hi Glenn

I have not built the mini but have several QCX here

Hans has a marvoules design try not to over think T1 on your first kit
Build you kit per latest assembly manual and enjoy QRP CW at its best
The onboard CW filter is a delight

Then later I enjoy ham radio at its best 'Experiments'
I read where others modify for special purpose
Bypass or mod the CW filter (how to search this list) for SSB? (upper or lower just goto MENU and REVERSE CW) and? WSPR for example
Yes QCX transmitts WSPR (FSK) but does not receive WSPR (FSK or SSB) you will need an app (k1jt) to decode WSPR after CW filter mod

Again In fact try not to over think T1
Hans kits are so well thought out they can and will function without T1 (ang how to here on this list) and become multi band (goto MENU then PRESETS)

Yes you loose some sensitivity on all bands but just add more antenna such as 132 ft InvL for example :>)

In some cases local high power broadcast can be an issue check out Hans wonderful low-pass es band-pass filter kits

see my? (qrz.com)? page?? 'QCX and fldigi captures WWV Twilight Zones' (no T1, no CW filter, no LCD (for power savings wnen batt ops)) while tooling up for 2023, 2024 eclips (hanSCI.org)

ps to share an ahHA-Plateau moment for me I discovered there are four DX Twlight Zones and four local Twlight Zones, Astronomical, Nautical,? Civil (first light), then SunRise for a total of eight that fldigi will save to a? ".cvs" file at one second intervals for EXCEL to plot :>))

yet just another facet on this marvoules ham radio hobby

72 73
John
N3AAZ
FM19 on DELMARVA Peninsula?

?Try this















Sent from my iPhone 6

开云体育

It seems the schematic got dropped off here as well.?

Are you talking about GPT4 or Chatgpt?, the latter is as you say sometimes full of BS. GPT4 is mostly a different story, and by the way, they both have no connection to the internet, so it does not compile Info from the internet, it uses tokens distributed through its neural networks just like humans.

Paul DJ0CU G4ADF?

With all due respect - Homes have circuit breakers, smoke detectors, and fire extinguishers for a reason......

It's not that we are purposely risky with electrical and/or fire hazards, but we recognize that components and systems can and do fail, despite operating within safe standards.

I would like more information on the diode solution to protect the BS150s, including the correct polarity for insertion of the diode into the circuit.? I already have ancillary low-profile copper heat sinks installed on my four QCX-Minis, all of which are running a 24/7 WSPR Duty cycle, I am hoping the diodes will help further extend the lifecycle of the heavily used components.? ?I have two dozen spare BS150s in bench stock, however, I've already ruined the thin copper PCB traces on both a QSX-Mini and U3S board by replacing BS150 components; I'm hoping to avoid or minimize replacements in the future.??

I do recognize the good advice to be cognizant of SWR and not push source voltage to the extreme, a common self-inflicted failure factor with these micro devices, but if adding a 10-cent diode will extend the MTBF I'm on board to give it a try.

Thanks?

Brian, AA5H / 3W90K?

On Fri, Sep 1, 2023 at 09:44 AM, Paul Harrison wrote:

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 am a bit surprised by this...

I've tested it against subjects I know about and it seems to be good at formulating plausible answers and compiling info available on the internet. IMHO this is already a big achievement and useful but not quite comparable to a "human IQ" even if the AI might be able to pass "IQ tests" designed for humans.

73 de Yannig - F4IUJ

The tip about not tightening the PA retaining screw too tightly due to a 5v trace running underneath it, triggered my inner doubt monster so I went back in and fitted a small mica shim under that screw head.?

Mine is built for 12v and, after a bit of toroid bothering, it puts out between 4.5 and 5 Watts on all bands.?

Another excellent kit and incredible value for money. Mine has already made CW contacts into Brazil from here in Scotland.?

Cheers,
Ronan
MM0IVR?

??

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