VA Cyber Range CTF for arduino RF transmitting competition flags.

In the VA Cyber Range, we like to do IoT and RF challenges. In this one, we use an arduino to transmit a 2MHz CW square wave which appears across the whole spectrum. Students have to use the SDR kits we provide (recommend the RTL-SDR Dongle ) to sniff around looking for a "low power, intermittent signal around the 150MHz range".

The schematic is as simple as a single wire hanging off the Arduino's ping D9, or if you want a bit more range, put a small 50 ohm coil from pin9 to GND to get more signal out there. If you want it to run all day, I recommend keeping hte LED off (prevent it from blinking) and even desoldering the power LED if you want the 9v battery to last a long time. Here's what the box I put it in looked like.

Here's a photo of the UVA & GMU students at the VMI CyberFusion 2020 conference. Good Times...

This is the SDR Kit kit I got from Amazon. It's one of the better RTL SDR kids as it includes the temp compensated radio, a nice set of rabbit ear antennas (to cover several bands) as well as a little tripod and glass/laptop suction cup.