I am playing around with an arduino and a cheap SDR dongle and I just noticed something strange!
When I play a tune on pin 13 with just a random piece of wire connected to the pin (Using the Melody example from the arduino page: http://www.arduino.cc/en/Tutorial/Melody) I can pick it up as AM sound on my SDR on exactly 64Mhz even as far as 15meters away through walls with a little gain!!!
What magic is going on here and secondly and maybe most importantly would there be a relatively easy way to pick up the signal using just an arduino and cheapo components?
(Just for educational purposes of course, I know that there is better options depending on what I need to send)
I would like any qualified guess as to what is going on, I am genuinely puzzled...