The QMX Resurrected

Well, after a well deserved break in WA I'm back home, and the QMX 3.3 Volt buck converter module that I ordered has also arrived. After some quick resistance measurement it was installed. With the supply voltage set to 7 volts and current limited to 200mA, I gingerly switched the QMX on. Oh the Joy of resurrection! It's alive again.

One Dead QMX :(

Well after the high of loading the beta firmware and getting the SSB calibrated and working on my QMX, a downer was bound to follow.  The other night I was listening to some CW and the QMX was decoding this reasonably well too.  (Better than me, actually!)  But I decided to connect the PC up and use the IQ output to get a waterfall display up and running using the NaP3 software. I plugged the PC in, using the USB-C connector on the radio, and then went to power it up.  Nothing.... no initiated boot up sequence....  dead!  

On inspection I could see that the 3.3v regulator was getting hot.  I switched over to another power supply so I could check the supply voltage and current, and I could see that the there was lots of current, so much so, that the voltage protection on the power supply kicked in. There was a short.  I removed the 3.3volt buck module and repeated the exercise.  This time their was just a few milliamps draw on pressing the on button.  I measured the resistance between the 3.3volt line and ground  on the main board and this seems normal.  These factors are pointing to the 3.3v buck convertor as the culprit.  But I'm still not sure why this failure occurred.  Was there some voltage differential between the USB-C connector and the 12 volt supply? Not sure.

Be assured an update will follow.

QMX SSB beta release

I just noticed that Hans has released a SSB beta firmware update for the QMX and QMX+.  This is only for the brave.

https://qrp-labs.com/qmxp/ssbbeta.html

The question is, 'am I brave enough?'

The answer is yes!  

I firstly, modified a microphone that was in the junk box.  The original curly cord had perished in the tropical climate.  And then I gave it a quick test.

An update to the firmware was released (as I was on the site).  This fixed a number of bugs, so I loaded the firmware (1_01_002 SSB Beta) into the QMX.  After reading Hans's calibration notes I duly followed them, with a dummy load connected.  The calibration does take a while, (as mentioned in the notes).  After the calibration a quick test and the QMX just works, as it should.  

This is an amazing achievement by Hans and all credit goes to him.  It has been worth the wait!

Calibration screen showing 20m USB Sync

 

The QMX, now with a mic!

  

Note: there has already been another update to the firmware. (21 March)

 

FT8 with my QMX and an Android phone

A few months back I build a mid-band QMX. I've not had the opportunity to play with it much, but that changed a few days ago. By brother, who is also an Amateur Radio operator, and about as active on the bands as me, was operating FT8 portable. I was 880km from home and had some time on my hands. So, I put up a long wire tuned in 20m, connected my phone to the QMX and opened the FT8CN app. After some minor configuration changes we were up and running. There were a few contact into VK2, (so I knew we were getting out) and then I could see VK6BI/P (my brother) in the RX window. after several attempts we managed a two way contact. This was a first on the HF bands using FT8.  4 or 5 watts was all that was needed.  

This was a bit of fun, so I must do it again sometime soon.

Ham Clock

The other day I came across an article about a Pi based Ham Clock. Given that I had a surplus 7 inch display in the junk box and a few Raspberry Pi SBCs, I thought I would give this project a go. 

There are a lot of configuration options, which took a little working out, but it came together well, and I am very pleased with the result. It has its own webserver so you can log into it from anywhere on the network, which is handy.

You can find the project at:-  www.clearskyinstitute.com/ham/HamClock/