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I used 7812 and there was slight noise. I returned to one diod instead and everything is ok now. 09:32, 11 April 2025, "Alan G4ZFQ via groups.io" <alan4alan@...>:

Do you mean the 7809 is producing RF noise? If so, then suspect the decoupling capacitors. A 7809 should be noise-free. 73 Alan G4ZFQ

Hello i have received my assembled QMX+ a few days ago and go the power cabled assembled feeding this unit with 11.80v of dc. (12v model) I can putty into it and see the hardware tests pass, the data

Just got my QMX+ last week in the US; DHL at least at the time didn't charge any brokerage. It's under $800 and so the de minimus applies. As others have noted, when I lived in Canada dealing with

Please share the details. Thanks and 73, Don N2VGU

I think you will be OK. Nothing has changed for US. Relax.

I'm using this amazing and cheap PC using a Raspberry Pi4-B with 8GBit RAM and Rasbian OS (a Debian Linux OS) sold at the low price of US$219 and working well. It has a choice of 2 OS to boot and I

Ok,,,, just for fun I thought I would try my QMX+ with my KXPA100 amp and *it works great*... puts out about 50 watts with QMX+ driving it. I made my first SSB contact in QRP mode on 20m the other

The wiki page QMX QMX_plus debugging environment ( /g/QRPLabs/wiki/39252/220346 ) has been updated by @Ludwig_DH8WN <DH8WN@...>. Compare Revisions (

Marek, did you check when displayboard is connected to the mainboard and also the displayboard alone? 2 - 3 7k is ok, my fault. 73 Ludwig

Hi Ludwig, Thanks for suggestion and info. I have measured resistance between all pins (2-3,3-4, 4-5....) and except pin 2&3 resistance it in Mohms, usually 5-12MOhm. However between pin 2-3 I have

Hello i have received my assembled QMX+ a few days ago and go the power cabled assembled feeding this unit with 11.80v of dc. (12v model) I can putty into it and see the hardware tests pass, the data

Hope you’ve got your fault protection sorted. Prospective short circuit will be 10kA and an auto fuse ain’t going to stop that arcing ..

"I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power

I built my QMX+ for 9v, then installed an LM7809 inside so it will accept 10-30vdc input. That solves the over-voltage problem (that killed my first QMX) but doesn't allow for adjusting the power

This is set by the SSB drive level parameter (900 drive level is equivalent to 90%), as described on the SSB beta page. So if I understand the description correctly, no, the modulator voltage will not

Thank you everyone for such prompt responses.? A buck converter is on its way! -- Jim, W7EZN? ? 73!

The 12.01V is safe. But are you saying that the voltage is dropping to 8.64V when you transmit? This is safe, and will work, but will give you lower power-out. How and where are you measuring this

YES! Mandatory. Roger 8P6RX ?Get BlueMail for Android ?

Yes you should limit the voltage to 12V. A buck converter or just simply put some diodes in series will do the job. -- 73, de BD8BTE op: Lun Yang