Hi Lee,

Great idea to use Audacity to create the visualisation!

I have been playing with the frequencies in the Nyquist prompt, and like the appearance of the data displayed when using :
(mult (sound (hzosc 10000)) (sound (hzosc 200)))
This shows the envelope effect very clearly. I guess with the frequency differences seen in radio transmitters/receivers, this is even more pronounced, but I haven't tried to load those values in!

My other comment: beware (enjoy) the functional programming rabbit hole. I stared with Clojure, then moved to Common Lisp, and more recently Scheme (Guile), as well as using emacs-lisp throughout. My use of the latter has improved significantly since I learned from the other functional languages. 

Thanks for the show!
--
Paul