I’m excited to introduce another member of the CTR2 family, CTR2-MIDI.

CTR2-MIDI (I’ll call it MIDI here) is a custom MIDI controller designed for ham operators using the iPad and Mac radio control apps developed by Marcus Roskosch, DL8MRE (SmartSDR and SDR-Control). It currently supports MIDI over Bluetooth LE (BLE). MIDI over USB may be available in the future. Marcus plans to add support for it to all of his radio control apps.

PLEASE NOTE: Marcus has been kind enough to add support for the MIDI to his apps, but he is not involved in the MIDI’s design or firmware. Please don’t waste his valuable time asking for technical support or feature upgrades to the MIDI. If you have questions please contact me.

The MIDI is a great accessory for Marcus’s apps. It provides a physical tuning knob, eight encoder options, six dual-mode pushbuttons, and a 3.5mm (1/8″) jack so you can use your paddles, a straight key, or a PTT switch with the app.

CTR2-MIDI’s are in stock and I can ship the next day after payment.

SmartSDR for iOS supports SmartLink so there is no need to forward ports or use VPNs to connect to a remote radio. Just connect your MIDI to your iOS device and you have the perfect remote operation setup.

The MIDI is powered through it’s USB-C connection. It can be powered by the iOS device, from a computer’s USB port, a cell phone charger, or a USB battery pack. A small 5000 mAH battery powers it for over 12 hours. It connects to the iOS or Mac device using BLE. No physical connection is required.

Unlike CTR2-Micro, the MIDI has no internal radio control logic. The entire radio user interface (UI) is handled by the iOS app. The MIDI only sends MIDI commands, it doesn’t monitor any of the settings in the app. Mapping the MIDI’s controls to the app is the only setup required.

NOTE: The MIDI doesn’t include any of the features of the Micro, such as radio CAT control, keyer, WiFi, web browser, etc. Therefore, it can’t interface to CTR2-Voice or CTR2-Display. The only feature it has in common with Micro is that it supports a terminal interface so you can calibrate the buttons if you build your MIDI from a kit.


I’ve added a video on CTR2-MIDI to my YouTube channel. You can view it here.


But I already have a CTR2-Micro

If the only reason you bought the Micro is for remote Flex control you may be a little frustrated with needing to forward your radio’s control port through your router or manage a VPN so you can access your radio remotely. Many Flex users operate remote radios provided by clubs or friends what won’t allow port forwarding or VPNs on their network (and for good reason).

I have created a version of CTR2-MIDI that runs on the ESP32-C3 processor in the Micro. You can download this firmware to convert your Micro into a MIDI, a “Micro-MIDI” if you will. The difference between the two hardware platforms is that while the MIDI has six buttons and four status LEDs the Micro only has three buttons and one status LED. The differences between the two are spelled out in the CTR2-MIDI Operation Manual. One of the nice things about this solution is that you can always reflash the Micro with Micro firmware to return it to normal operations.


Mike, WB6DJI, has also posted a YouTube video on his remote operation of W6HA. He’s using his CTR2-Micro running CTR2-MIDI firmware.


I hope you find this new addition the the CTR2 product line useful. As always, if you have any questions or suggestions, please contact me. My email address is good on QRZ.com.

73, Lynn, KU7Q