QRP Labs 5W CW transciever kit #4

So I’m into week three of Aussie Flu and I’m resembling a Wookie more than a human due to my facial hair. With the cough I’ve got there’s a definite intergalactic walking rug roar going on!

I must admit to starting to climb the walls slightly more than a little as I don’t do ill, but have tried to keep my brain occupied if nothing else by cracking on with my QCX kit. To be honest when I get back to work I won’t have the time so lets make hay while the sun shines.

We left the saga last time with me unable to find my capacitive touch key so I was unable to fully test the little rig. In the end I gave up and rather grudgingly lashed out on a Palm Radio Pico Paddle. I only say grudgingly because somewhere is a perfectly good home made paddle which I really like but I’m buggered if I can find it. The Pico Paddle is lovely and does the job nicely, so I eventually managed to hook the QCX up and give it a go.

The rig requires alignment and the manual walks you through the various calibration steps to set the radio up. It’s worth spending the time to do it properly and I wasted an afternoon playing.

One thing that a lot of people have commented on is that the radio needs to be housed inside a screened enclosure to prevent stray RF causing issues. That aside this thing needs to be portable as I’m sure there will be an FPARC show and tell when everyone is done and I wouldn’t want my hard work getting ruined in transit. For speed I “borrowed” an idea from Mick M0GWD from the club who is very talented when it comes to enclosures and graphics. He very kindly sent me a copy of his drilling pattern which gave me a starter for 10 but I’ve got a few changes of my own to implement along the way.

I’m using a Hammond 1590XX aluminium enclosure for this and the board and associated wiring fits nicely, or at least it should!

So with my template glued to the case with Pritt Stick it was time to start chain drilling out the LCD cut out. I took my time as the screen is the focal point of the unit and I wanted it perfect.

I revisited that cut out over and over with needle files in all sorts of light and with  a variety of T squares and set squares before I was happy.

Circular holes are slightly easier and for once, rather than using a smaller drill and expanding the holes with needle files I lashed out on some intermediate size drill bits for some of the connector and rotary control entries just to get it right first time. Trust me it’s worth it.

After a thorough clean in hot soapy water the raw metal enclosure was washed down with IPA to degrease and to remove any water residue. We could have gone naked but I decided that this QCX was going to be both loud and proud in the colour department so it needed priming and painting.

Typically, I ran out of primer in the last few applications and just as the daylight was going but I think it’s sufficient for government work! That can cure for 24 hours before I hit it with a colour layer or five!

Meanwhile I decided I was going to mod my QCX on the PCB as I was suffering the unreliable microcontroller start up issue that other builders had been experiencing and thought while I was wielding a  soldering iron I’d apply them all for completeness. This involved relocating one of the inductors (L5) supplied with the kit and adding a few resistors in key places on the underside of the PCB, not unlike in the K2 build.

With all of that done, the next stop was to add a GPS receiver to the kit. Apart from making the WSPR functionality of the kit so much easier, it also provides a reference source for calibrating the radio further.

This is QRP Labs QLG1 and I bought it at the same time as the QCX kit. If you use this rather than anything else its a simple 4 wire hook up to the rig and saves a lot of hassle. Now when I’ve tried to hook GPS antennas to kits before I’ve got into all sorts of trouble with broken wires in cables, at entry points and on plugs.

Not this time, I had a flash of inspiration and paid a whole £1-90 for someone to do all the hard work for me in the form of 3m S-Video cable from eBay. Nicely built and screened with moulded plugs it was a no brainer. I just lopped one plug off, worked out what went where inside and soldered it to my GPS puck.

Job done. I also invested in some decent quality chassis mount 4 pin mini DIN sockets and made myself a little jumpered connector to fit to my QCX board.

One screened durable GPS lead of the required length. All that’s needed is a nice little enclosure to mount the GPS unit in. I’m very tempted to 3D print one, just to justify buying a Prusa i3 Mk3 but may just wimp out with a plastic box from eBay – you never know.

Anyway, this is where we are so far –

All I need to do now is come up with a suitable decal pattern to finish off the enclosure once painted and we’re done.

Here’s a quick video of the rig in action now I’ve got it all working nicely.


To be continued . . .