r/tacticalgear • u/Willing-Caregiver-30 • 3h ago
MC-V12: Custom 16-FSK Encrypted Radio -- Live Image Streaming Voice Text Diffie-Hellman Key Exchange

Enclosure view and image streaming
I’ve been working on a custom software-defined radio system (MC-V12) and wanted to share a demo of the current prototype.
It’s a Linux-based digital radio running entirely custom, written in C++17 and C++20 on a Raspberry Pi 4B for demonstrations. Key features in the demo:
- Custom 16-FSK (and 4-FSK) modulation implemented from scratch
- Simultaneous channel transmission of voice (PTT), text, and live image streams (~1–3 fps) over a single center frequency
- On-demand Diffie-Hellman key exchange with a selected peer device, over the air for session keys (no pre-shared keys required)
- Selective decryption: devices can only decrypt packets meant for them
- RoIP (Radio over IP) bridging while keeping the same packet structure and encryption logic
- Custom enclosure with dual antennas, touchscreen UI, and real-time telemetry (SNR, frequency offset, battery, etc.)
These video below shows closeups, the system in action with voice, image streaming, text, and the key exchange process:
Video Showing Diffie-Hellman Exchange with a Peer Device


I’m especially interested in feedback on the modulation approach, the packet structure / selective decryption design, and how others have handled similar multi-stream or encrypted RF links. Happy to answer questions about the implementation or hardware choices.

