开云体育

My audio sweep on a newly built (by me) QMX is showing levels of around -22dB as the max value. The wiki for the PCM1804 ( /g/QRPLabs/wiki/37111 )? says there is a problem if the

Bill Email address or callsign?? 73 Paul w2eck

Lots of good ideas here, thanks, everyone. The LF4100 looks like the cat's meow. The USB-C power bank with a module to get it to output 9 V on the line is a pretty good argument for building for 9 V

Alan, I have a low signal on the audio sweep, but the wiki says " very low level from audio sweep" . I will start a new topic to see if anyone has the definition of "very low". Thanks for your

1_00_026 working now. Turned off QMX+ and on again ....twice.. Not seen that before...sorry.

Hi Folks, Does semi-qsk work with straight key mode? It doesn't seem to. I understand the "dit"-space setting doesn't make sense but should the ms timing work? It seems to be about a second-plus and

Hello Ludwig Actually the PA modulator is set to High during RX, this was a JZ suggestion, as it would apply maximum reverse bias to the BS170 MOSFET body diode, minimizing it's capacitance, and

Since installing 1_90_26 neither of my Windows computers recognizing QMX USB. WSJTx not working, of course.

Bill, there was a bug in the f/w where the tip and ring settings were reversed. So if you had a mono plug- in the past Straight key setting needed to be Ring, now it needs to be set to Tip, which is

My Talentcell LF4100 has such an arrangement, the 9V output is regulated BUT the "12V" output is 4S LiFePO cells unregulated and can go over 14V. I use a buck-boost module to tame this to 12.0V and

Thanks! I'll have to purchase a new board. I removed D109. The function was better, but VDD? has been off a bit and sometimes higher as 4V. so I decided to try it with 12 V... ... with PWM 3_3 still

Peter, Before you invest in new power boards, I suggest verifying that Vdd is not shorted to ground on the main board.? That indicates MPU failure that can only be fixed with a new

Don't know of any book or website, but here is the first comments (including opinion) I would make: The modes with WSJT-X type applications pretty much send automated transmissions and (typically)

Dr Ramsey We have used this since 2022 for 12 volt QCXs and 9 volt QDXs. You may want to regulate the voltage for the QMX, as many have said, and Hans has suggested. Careful , Careful..... A week on

Hi Hans, but now I'm confused. In my understanding in QSK mode during the gaps between keying the QMX is in RX mode and so the PA voltage should be near 0V (0.4 V or so) like shown in Diagnostics

This was mentioned a few days ago. I think it was a bug, now rectified by new firmware. The difference in the cables was that a

There have been some upgrades to the power supply boards to make them more robust over time (higher wattage zener, higher voltage tantalum capacitor). So depending which Rev QMX pcb yours was built

I've found different impedance phones make a huge difference in the volume of the audio on all QCXs I've used. Make sure you're comparing like with like. 73 Steve G4EDG

Peter, use the assembly manual section "PCB diagrams". Ok it's a lttle bit hard to read D109. Afaik it's the diode at the edge of the PCB and close to D103. Zoom in in the PDF and you will find

The ARRL bookstore has a "Get on the air with HF Digital" book.? I have it and it's pretty complete. The published docs for each of the digital mode software are also pretty complete. Mark KD0QYN