So [Todd] has set out to build an Arduino frequency counter for a Kenwood TS-520S HF ham radio. This post (and the video found after the break) doesn’t cover the entire project.

He didn't have a license on it so I hope he doesn't mind me making it public domain: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license). This ...

At the moment, this just outputs an average time between bubbles to the serial port, but [Waldy45] is looking to add an ESP8266 to wirelessly connect the Arduino and contact him when the bubble ...