The Contraption - 3D Files Available for the Preview Version

The Contraption is a 3D printed case for creating a handheld HF radio out of a QRP radio + battery + antenna. It is ridiculous, but fun.

With the Contraption, you can turn your QMX or QCX-mini (and someday CFT1) into a handheld portable HF 20m radio. For morse code, you can use a magnetic key mounted to either side or plug an N6ARA TinyPaddle into the bottom. Soon, we will also release a magnetic mount on the side for a tripod mount phone holder.

The files are available now (of this early version) for anyone who wants to try it on their own 3D printer. We will continue to provide the files for free for those who wish to print their own, and we will soon be selling it as a kit with the 3D printed parts and hardware so that you don't have to source your own. Regardless, you will need to supply your own QRP radio, battery, antenna, morse code key, and cables.

Don't have a Just OK Mini antenna yet? go grab one as kit! You'll need one with The Contraption.

Disclaimer: Please enjoy this project at your own risk. Mike broke his favorite paddle already. Due to the nature of it, it is possible if not even likely that you drop something and break it. Also, as always use caution when playing radio outside – don't walk in front of cars 🚙 or into trees🌲 when pedestrian mobile, always be cautious of power lines, etc.

Free files for 3D printing

Below are the .stl files to use for 3D printing. Please note that we aren't able to provide 3D printing help. While we do a TON of 3D printing, we aren't experts and only have experience with our printer. We do hope that if you don't mind potentially wasting the filament, that you will print them and give it a try!

License: Free to print & remix, but noncommercial: 📘 CC BY-NC-SA

Here is an image showing the orientation we printed ours in. We printed on standard mode with 3 wall thickness and auto supports turned on. The filament is bamboo brand PETG - HF.

Optional

Optionally, this tripod magnet mount can be used to hold your phone on the side. You need 3 very strong magnets super glued in, and a tripod phone mount.

Magnets: https://amzn.to/4sFjcUx

K8MRD Mike Redux

Mike K8MRD made a modification to The Contraption with some great ideas. He made it a little bigger to fit the newer smaller INUI battery and added a window to be able to see the current power level. He also moved the hole in the bottom for the power cable and made a change for cleaner tear-offs of the supports.

We will incorporate his changes into the design of the official version, but if you have this smaller battery and want to try his modified version, here is the file. It is a .3mf file which includes the design and Bambu Lab slicer settings.

The Contraption for CFT1

Jonathan, the creator of the awesome CFT1 radio, designed a variant of The Contraption for the CFT1. He also improved the design to print without supports! Check out his version on Printables:

https://www.printables.com/model/1633398-the-contraption-cft1-edition

Roadmap for Official Version

• Add more space for metal plates (some people had to sand them down)
• Incorporate Mike's changes (battery level window, different versions for a few different kinds of batteries)
• Incorporate Jonathan's improvements to print without supports

Other things you will need

• QMX or QCX-mini (version for the CFT1 coming soon)
• USB PD battery
• Short 12V PD Cable: Amazon or directly from Digirig
• Just OK Mini: ridiculously small 20m portable antenna
• Morse code key with magnetic base or Ara's N6ARA tiny paddle
• 2x of 2.5" x 1.42" x 0.07" steel plate
• 1/4"-20 Heat Set Threaded Insert for the top antenna mount
• tripod thread adapter to attach the top to the antenna
• short 6" BNC cable to connect to the antenna to the radio
• short right angle audio cable to connect the key to the radio (if using magnetic one on the side)

Looking for the magnet mount for your phone that goes on the side?

We don't have that available just yet, but stay tuned!

If you want more info, here is another video: