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Are you sure you don't have the supply voltage reversed! (If so thank Hans for the reverse protection) Sounds like an issue with Q103 or Q105. I would check that there is nothing shorting between pins

Hello Ryuji I'm not sure there's any politicizing. I just felt as the designer of what is, I believe, a high performance transceiver, I should explain why L401 was used and why I think it is important

Hans and Don, I totally understand what you are saying, but what I said is actually on the same point. The discrepancy between the RMS power and "power" converted from the peak voltage is of the same

Clarification: While holding down the power button, the DMM on the current setting reads -.23mA. When I let go of the button, the DMM reads 0.0mA.

Enameled wires have different characteristic impedance depending on the wire thickness and the thickness of the enamel coating (thickness more important than material in this case). Mixing slightly

That's a great story.

“Awesome” only gets close! Wow! Amazing! Love it! Dave

I would check the main board for shorts or near shorts on 3.3v and 5v to GND. ?If that looks good, replace the SMPS boards. ?They can be repaired but it’s not worth it since Hans will sell you a

All, Let's not politicize an engineering decision. It's free to keep L401 or delete it in your own QMX build for self-satisfaction, but I feel that this thread has become campaigns trying to persuade

Try using it with FlRig. 73 Dave. -- David Thomas M0OOR

Spectacular! I enjoy Hans stories at least as much as his products! 73, Willie N1JBJ

Hello all, My newly-built QMX does not draw any current and, of course, does not turn on. When I press the power button, the DMM on the current setting reads -.23mA. Here is what I've checked so far:

My fix for trifilar windings is to use different colors of enameled wire. Within reason, you can use different sizes of wire, too. Oscillator coils from old television sets are an excellent source of

General statements about components: 1. Identify the environment they must work in. (temperature range, shock/vibration, altitude, space or automobile qualified, etc as necessary 2. Identify the

I totally agree with Hans here on the L401. Deleting the band pass filter in QMX would, IMO, ?probably turn it into a uSDX! With all the respect to their unique design disclosing the Atmega

Hello group. This is my first post--wow, reading this list is akin to "drinking from a fire hose". Two weeks ago I purchased a QMX kit to use as a WSPR beacon during the eclipse challenge event. The

look at https://www.farcircuits.net/rf_amplifiers.htm Drop down to the Mousefet amplifier board.? This is a Class C amp from way back? which has a 2n3866 preamp built in .? I think Fred's version

Hi Jim It doesn't seem that the connection problem is related to the QMX itself. Something on the mac or in that particular software. Another thing to bear in mind, which could be a misunderstanding

cw mode received transmission current is still 0.1A, no change, but there is transmission code under cw, 555 kilometers away websdr can clearly hear, but the current is still 0.1A, I need to check

Hello Damion Thank you ;-) Current draw will be higher at lower supply voltage, as is characteristic of SMPS buck converter systems. However if you are saying 140mA is at 12V supply, which I assume