Building a K16 CW Keyer for the QCX Mini

The marvel that is the QCX Mini is already equipped with a rudimentary electronic keyer for Iambic modes and including memories, beaconing and practice modes but I wanted to add a K16 keyer for increased features.

The K16 Keyer from Steve Elliot K1EL is perfect for both contesting and casual use and fits on a PCB measuring just 38mm x 35mm. I am using the Kanga UK version of the board available here. Detail of the full range of keyers from K1EL (US site) are here. The K16 chip can be purchased separately if you wish to design your own PCB here (US) or in the UK, again from Kanga UK, here.

Further details of K16 features and operation can be found here.

I have previously built a K14 keyer into an Altoids tin but on this occasion I am salvaging a defunct USB soundcard case to build the keyer into (matches the QCX Mini styling) and will be supplying the power from 2 x CR2032 cells (the keyer only draw 1mA when on and uA when in standby mode) rather than the larger PP3 specified by Kanga.

This is the original soundcard and box:

The K16 keyer in progress:

I intend to integrate my old K14 Keyer into my 20m QCX (vanilla).

Getting started with the QCX Mini

The QCX mini is a high-performance single band HF QRP CW transceiver kit available for just $55 with a 50W amp for an additional $29.50.

My QCX Mini kit from Hans Summers QRP Labs arrived just before Christmas and was sitting under the Christmas tree for me to open. I’ll be documenting the journey with some links to other useful sites along the way. Watch this space!

A bag of goodies! (actually 3 bags, the LPF bag is under the main component bag)
For scale against my watch
Checking the PCB, no obvious errors under the eye loupe
Earlier stages … transformer took about 30min to wind and install after checking continuity is correct and copper wire enamel removed with solder (10 seconds of heat … one thousand, two thousand ….)

Made sure to install the IC holder as far to the top of the PCB as possible to ensure sufficient space for the paddle socket and the TCXO board.

40m transformer
A few more caps fitted
1. BPF and LPF toroids wound and fitted (wondering if I should have wound them differently to allow for adjustment).
2. Multi-turn potentiometers added for alignment.
3. PCB connectors added for subsequent fitting of control board.
Getting there with the main board.
1. All 3.5mm sockets added (bottom right looked a bit skewed but lines up perfectly with side fascia)
2. BNC connector added (although wondering if I should have used an SMA?).
3. Main board almost finished – must remember to add a 10uF electrolytic across D33/voltage regulator IC.

Main Board connects to the display board …. phew it fits 🙂
She’s alive!

Now for a nice cup of coffee before alignment this evening

Alignment now done, no issues (once I had fixed a dodgy soldering joint on the TCXO!). I followed Hans’ video here: (117) Tuning up your QCX+ – YouTube


Initial findings are that it’s receiving very well and RF output at 12V is just a shade over 3W.

Having a Bud to celebrate progress so far!

Not a great quality video but enough to show progress, (Dodgy polarising filter over the LCD to prevent it washing out my iPhone camera!).

Transmit test to follow …

Testing the Mini QCX in WSPR TX mode:

My very first transmission tests on WSPR:

And the results – AMAZING – Decoded in Antractica on first transmission, how excellent is that for something that was a bag of components 2 days ago!

39 decodes in one transmission (first ever WSPR on my Mini QCX)

Received on both receivers at DP0GVN – Neumayer Station III
Ekstroem Ice Shelf, Atka Bay, Dronning Maud Land, Antarctica

Top 50 spots, all over 1000Km in less than 10min (note only ONE station is reporting drift). Ignore the power shown as 5W, it’s actually 3.6W!:

Top 50 in 10 mins

… and also DP0POL/MM the German Ice-breaker Maritime Mobile (at this very moment the Polarstern, a German research icebreaker is presently off the coast of Africa en route to the scientific station in Antarctica. )

Time to play with CW I think …

No reply to CQ call but picked up on the reverse beacon network in USA and Russia.

Now to bed … Looking forward to some CW QSO’s tomorrow 🙂 Anyone for a QCX to QCX sked?

I am going to put further WSPR posts here:

First CW QSO on QCX Mini – Willi DL2IAD

Very pleased to report working Willi DL2IAD (Herschweiler-Pettersheim, Germany) this morning on the QCX Mini. 599 both ways, a solid QSO. Exactly 600Km IO91SO <> JN39QL.

First QCX Mini QSO – 600Km with DL2IAD

Second QSO on QCX mini GM4ENF 489 (Al in in Cupar, Fife, Scotland)

Boxed up and finished! ( ….. for now!)

A few minutes in the New Year’s Day German AGCW contest on 40m using the Mini QCX


Reference Materials for the QCX Mini

QRP Labs: QRP Labs Kits (
The QCX Mini: QCX-mini 5W CW transceiver kit (
Order your QCX Mini here: QCX-mini 5W CW transceiver (

In the build I will be following some of the useful tips by Ryan Flowers (including his YouTube videos), link here:

I’ve just noticed that David Casler (Excellent YouTube channel by the way) has just received his QCX Mini and will be describing his build here: (117) The QCX-Mini 20m QRP Rig Kit Arrives (#342) – YouTube)

A link to Hans Summers QRP Labs videos including on the QCX Mini and a ‘lab’ tour is here:

GQRP Convention 2020

Thank you to Steve Hartley G0FUW and all the team at GQRP for the excellent virtual GQRP Convention run over the weekend 5-6th September.

A thoroughly enjoyable event. I have attended a number of the conventions in person over the years and was a little apprehensive about how well it would run as an online event. Whilst I admit I missed the face to face conversations and annual ‘meet-up’ given the circumstances this year I thought the event was a huge success, so much so that I hope the online element continues in future years – if nothing else it provides a much greater global reach and provided a valuable source of videos to watch over again for ideas and stimulation.

A link to the event webpage and links to all the presentation (now on YouTube) is here:

A direct link to the GQRP YouTube channel is here:

Playing with the uSDX

Intrigued by the potential I have converted a spare 40m QCX from QRP Labs into an SSB transceiver, it’s not without it’s issues but it’s remarkable piece of coding. Here’s mine boxed up (groovy orange 44870 LCD unit!).

An earlier manifestation of my build, do you think I need a bigger VFO knob?

Here’s a short video of it working on receive:

Everyone loves Brew Dog IPA!

Here’s me playing with FT8 and the uSDX using an ancient laptop rescued from the bin!

Guido’s GitHub page full of QCX-SSB info, manual, schematic and firmware (*.ino):

If you want a technical explanation of the coding, look at Guido’s page here noting this began with work on a RPi back in 2013:

The latest version of the QCX is this QCX Mini and Hans has kindly included a PCB module to enable the uSDX to be built into the Mini. Alternatively you can ‘go the full hog’ and build the uSDX ‘sandwich’, full details are at the DL2MAN website here: DL2MAN´s HAM Radio Page – home of the uSDX Sandwich, it’s also worth checking-out DL2MAN’s YouTube channel here: Manuel K – YouTube