开云体育

Dan, take a look at this thread. You may be having the same problem. /g/QRPLabs/message/107812

Check for contact between pin 3 on the LCD module, and the inductor housing, on the power supply board above it. This will cause the backlight to wash out the display, like you are describing.

And, of course, the third question is if adding the commutating diode and/or the zemers will affect the output characteristics (spectral purity, spurs, harmonics), in such a way as to render

Hans & John, Thanks for the excellent explanation! I'll add the 1N4148 to L14. I can't see that it'll do any harm anyway, and it probably will help. -- 73, Dan? NM3A

Hi all. After slooowly assembling my QMX main board, I finally completed mounting all the electrical components. I don't any issue with the potential buck regulator short issue. I measured all tthe

Yep, that would certainly make sense, and has been mentioned before. However, it would require a fairly major revision to wsjtx, and since it works as is (even if it’s not technically the most

QCX 40 has been sold. -- 73/72, Dean K5DH

Suppose that WSJT-X could be modified to side-step the whole 'translate the desired rf frequency to an audio tone, send the tone out on an audio cable to the radio, where the tone is mixed in on the

Dan, The QMX has a PMOSFET modulator that can gracefully ramp down the supply voltage to the power amplifier stage, under digital/MCU control. That circuitry is essential for the QMX wave shaping

I think I use 120 ohms in my builds. -mike/w1mt

I am finding the brightness of the QMX display to be too high. I want to increase R306 (33 ohms) to lower that.??I'm thinking about 100 ohms. Any other suggestions as to what would be a good

Hi Dan RF envelope shaping requires amplitude modulation capability for the PA. QDX does not have this, QMX does. 73 Hans

John, Your explanation of QDX L14 makes sense. It doesn't seem to be a serious problem for semiconductor failures tho. More of an issue for spectrum 'dirtiness'. The diode would take care of both

Not too late, Bev - I added a note to your order. 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl

As a final test I fed the QMX with two external regulated supplies, 3.3v and 5.0v and provided for ADC_3V3 and ADC5V with two potential dividers. Unfortunately, the QMX reacts in exactly the same way

ND6T has pointed out that this can be done with an external adapter that will leave no permanent modification to your rig and could be used with any homebuilt

I don't think anyone is arguing that the diodes are the best solution to the problem long term, but they can be done now with minimal cost and effort, and will help protect your hearing.? They will

Link appears to be dead or broken Bob KG5GTE

Hi Hans Is it too late to ask for 9V option for QMX serial 72387? Regards Bev COAA Portugal

Whoppie!!!! 73, Cliff, AE5ZA