Daniel Marks' RFBitBanger Is a QRP Radio Kit for the End of Civilization — or for Fun

Daniel Marks, PhD has created an off-grid QRP (low-power) radio kit, designed for ease of assembly and use of readily-accessible parts — including an Arduino Nano or compatible to tie all the components together, and boasting a novel microcontroller-compatible digital mode dubbed SCAMP.

"The RFBitBanger is an off-the-grid QRP radio. It is not just designed to be used off-the-grid, it is designed to be assembled and maintained off-the-grid," Marks explains. "Most radios require specialized parts that would be difficult to obtain in an extreme parts shortage or in remote places. This radio is designed to be assembled and maintained using the most common jellybean components that might be in a hobbyist junkpile. It will mainly support low bandwidth/digital modes to make the most of limited power."

The heart of the board is an Arduino Nano or other Microchip ATmega328-based microcontroller board, which ties into other common parts: a LM358 ap-amp, LM386 amplifier, 2N7000 MOSFETs, 2N3904 NPN transistors, SS8550 PNP transistors, and a HD44780 LCD display as part of its user interface with input provided using a PS/2-compatible keyboard. A 50 ohm output can be used with an antenna as simple as a length of wire, with a built-in RF ammeter allowing for quick length adjustment to maximize radiation at the radio's low power output.

"The radio has a novel digital mode called SCAMP, implemented on a ATmega328P (Arduino processor) which performs coherent FSK [Frequency-Shift Keying] demodulation and forward error correction to achieve excellent performance in weak signal conditions," Marks adds of one of the radio's more unusual features. "No PC is required for this digital mode; it is implemented all on the Arduino. The mode is designed to be simple to set up to make it easy to initiate a contact."

"This design was started after a discuss on the Collapse OS mailing list about hardware is maintainable even without access to parts suppliers," Marks continues. "Projects such as civboot seek to provide a means of resurrecting technology and infrastructure after a catastrophic event. This design is to provide a means of communication if other forms of communications become unavailable, especially in rural areas or urban environments with compromised infrastructure."

Design files, a 3D-printable case, and source code for the project have been released on GitHub, under the Creative Commons Attribution-ShareAlike 4.0 license and ZLIB license respectively; a kit of parts is being offered by the Open Research Institute in exchange for a $150 donation, with deliveries scheduled to begin at the end of the month.