Success! Amid the plethora of exams, psycho-motor tests, and other crazy shenanigans my dental school is putting me through, I managed to do something truly productive! Check it out. I built a simplest-case QRSS transmitter with an ATTiny44a micro-controller clocked by a 7.04mhz crystal which generates FSK signals and modulates its own frequency by applying potential to a reverse-biased diode at the base of the crystal, the output (CKOUT) of which is amplified by an octal buffer and sent out through an antenna. As it is, no lowpass filtering is implemented, so noisy harmonics are expected. However for ~2$ of parts this is a pretty sweet transmitter!

I was able to detect these signals VERY strongly at a station ~10 miles from my house. I haven’t yet dropped in a 10.140mhz crystal and tried to get this thing to transmit in the non-official QRSS band, but when I do I hope to get reports from all over the world! This is what it looks like:

The cool thing about this transmitter (aside from the fact that it’s so cheap to build) is that it will work with almost any crystal (I think below 20MHz-ish) – just drop it in the slot and go!