I'm glad it was reposted, missed it the first time. I know Morse code (old school ham operator), and it seemed really obvious to me especially after reading the article, but I can also see how it wouldn't be obvious if you didn't know Morse.

It says 2015 in the article URL.

This isn't a dupe by HN's standards because it's been well over a year since the article was discussed.

https://news.ycombinator.com/newsfaq.html

...Read the comments in that link. Informative and well worth it.