I was originally interested in RTLSDR after seeing Melissa Elliott’s Defcon 21 discussion on “Exploring the Noise Floor.” where she shows how you can view information emitted from computer monitors for very low cost. If you haven’t seen it, I definitely recommend it. In any event, I decided to pick up the RTLSDR device she talked about here.

After I got the fc0013b, I talked with some friends in RF communications to see what may be the best “wide-net” antenna. They directed me to this blog which has a handy program to calculate the physical size of a discone based on the lowest input frequency (A note to the would be builder: grows QUICK based on the lower start frequency. I found 80 MHz OK based on my needs, YMMD).

Anyway, here is my Imgur album of interesting signals (including POCSAG) and parts of my discone build. I got signals in the 80 - 950 MZh range.

Here is a video at about 419 MHz that I believe to be packet radio.

Here is a video of me hitting my car key fob in close proximity.