On the topic of CW training, my daughter used an earlier version of this http://www.g4fon.net/CW%20Trainer2.php many years ago and she really liked it. 72 SM6LKM Johan

Hi, check the 10k resistor R46 on the main board. It's a pull-down resistor for the BUTTONS net. It becomes the lower part of a voltage divider when the buttons with resistors (R44, R45) are pressed.

Hi, another way to avoid that hazard is to cut the +5V PCB close to the PTT jack on the QCX mini PCB (unless you need that +5V for other purposes of course). As far as I can see in the schematic, the

#qcxmini #qcx #ptt

Hi Wolfgang, have a look at Spectran or Argo by I2PHD http://www.weaksignals.com My old (2006) SAQrx also contains a simple audio spectrum analyzer, 0-22 kHz https://sites.google.com/site/sm6lkm/saqrx

#qcxmini #qcx #ptt

It's still on G0KAY's Youtube channel, here: https://www.youtube.com/watch?v=-Tm8vA5Fqzw 73 de SM6LKM Ted 2E0THH wrote:

Perhaps you can find a similar jack at Reichelt Elektronik https://www.reichelt.com/se/en/phone-audio-jacks-c7445.html?&nbc=1 73 SM6LKM Johan Den 2021-03-11 kl. 18:37, skrev dl9hda@...:

Yes, R48 the current limiting resistor for the LED backlighter of the LCD. This resistor should become quite warm as it dissipates 300mW or so. 73 SM6LKM Den 2021-03-15 kl. 13:48, skrev Mehmet Dinch v

#qcx

Hi, I just finished building my 40 meter QCX mini and I'm happy to report that it works very well! Assembly went smooth thanks to the *excellent* manual. The only problems I faced was an LCD bezel tab

Hi, according to the version 1.07 manual, double clicking the encoder knob should toggle the LCD backlighter on/off on QCX mini. I tried it with backlighter both on and off in menu 7.11 but it doesn't

Thanks! I increased the double click time to 500ms according to https://groups.io/g/QRPLabs/message/58387 and now it works! (unless I triple click too fast ;-) ) 73 de SM6LKM Johan mike wrote:

Edward, C14 is a part of the first lowpass filter stage around IC8B. It is not extremely critical so just about any 1nF / 1000pF / 0.001uF capacitor with a few percent tolerance or so will do the job.

Yes, but keep in mind that JP17 pin1 is connected to the internal +12V rail so you are measuring the supply voltage after the foolproofing/lifesaving diode D33 which is 0.4V, or so, lower than the act

Hi, is there any knowledge/experience about how much abuse the QCX PA can withstand without damage? If a low loss SWR meter is used, the impedance seen by the PA will deviate wildly from the 50+j0 ohm

The board has no pull-ups on the paddle lines as far as I can see so it's a mystery if pin 19 gets pulled up when the MCU pin is disconnected from the socket. Look for solder bridges etc. The MCU has

#qcx #min

Hi Jerry, the 40m and 20m models differ only in a handful of capacitors and the number of turns on the toroids. Both versions use the same toroid cores. Look at the tables for "Band-specific capacitor

😂 73 SM6LKM jakob@... wrote:

If you have a QCX Mini, just swap the wires/lines ROT_A and ROT_B from the "CONTROLS" connector on the main (big) schematic diagram or swap the wires from the rotary encoder to the corresponding pins

That was fun to read. I did something similar with a PIC MCU many years ago. I put a lever on a pot with spring return to center position. Much like a 1-axis joystick. I remember that the software had

Hans Summers wrote: Back in the days I visited all of your H&P links. I implemented the shift register delay "fast version" on a PIC with good results and I had a lot of fun! :) Thanks Hans! 73 Johan

Tony, there are bistable relays such as this: https://www.electrokit.com/uploads/productfile/41017/HFD2_en-2.pdf It needs just a short pulse to switch to "the other" position and it stays there withou