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Somehow the Q103/Q104 short issue must become common knowledge for QMX builders. I found out only after the smoke came out on power-up. (D101) I certainly hope that the rest of the radio survived this

For the PWM signal on a test-board, I was just thinking of a free-running 555 timer.? Low parts count, inexpensive, just to prove functionality. Google "555 duty cycle"; there are several YouTube

That was a joy to read, thanks Joerg 73 Rod G0VKX once was G8FJN

To answer my own question, PJ324 seems to be the common part number. I didn't see them on Mouser but found ten pieces for under $5 with shipping on Ali Express.

Thanks Peter All agreed, I will make it so... 73 Hans G0UPL http://qrp-labs.com https://buymeacoffee.com/g0upl

Do you have a picture of your L401 you could share? 73 Karl KI4ZUQ

I forgot to mention, it was QDX in my case. 73 Pawe? SO8FM

Like I said in my first post those were bought used from I private seller, not new. My Paypal transaction has nothing to do with you, but with the seller who sold me two non working transceivers. If

Charles, just installing Ubuntu 22.04 on a test machine. 22.04 uses *PipeWire* (https://pipewire.org/) rather than PulseAudio. Checking the audio levels just now, the default audio level is *not*

Hello Daimon I had exactly the same with my Oppo Reno 4, I already posted it in other FT8CN topic. I think it might be something with hearing protection functions of the phone. Anyway the solution

Chris, You can use the cap values and design for the QDX HB 17/15m LPF just get the most recent assembly instructions and look at the cap values and L values there. 73 Ross Sent from my iPhone

Indeed, that's why I didn't. I try to have the attitude to hardware and software that it's broken, in the worst possible way, and remains so until it has been tested and demonstrated that it isn't

QMX is still young, but I believe so far the only two instances of BS170 failure I have seen reported here can be connected with a failed clock generator leaving the gates of the BS170s stuck high.

The QMX has two options for backlight: On and Off. In addition there is a triple click with left button that temporarily overrides the setting - well, sort off. If the back-light is set to ON, the

Chris, Yes, that too can be done, but why? Once you have safely demonstrated controllable continuity from input through to load, you are done. All the transistors are working. You don't need to put

Can the firmware protect against a power failure during transmit? I need to press the button on a Digikey order for a number of things, including the Zeners (#1N4756AFS-ND).? Ordering 10, could send

Hi Chris QMX doesn't do a sudden switch on or switch off so there's no spike on QMX. I'm keen to know any detrimental effects of zeners on transmit harmonics, and receiver noise floor and dynamic

It wouldn't be impossible to have a test fixture with a small microcontroller to read the ADC output and use that to generate the PWM pulses. I've made a speed controller for an electric motor that

Hi Hans, I hear what you are saying but I am seeing a significant number of reports of blown BS170s and sometimes their driver IC, I don't think they are all down to people thinking 12V means

Invoking PayPal is extremely unfriendly and unnecessary. You can email me. There are certainly no scams here. If they are kits it probably just means you built it wrong. If assembled units, they're