An interesting post from the Project Loon folks on their floater. It includes some time lapse of a burst. Ah to have a budget like that... https://medium.com/loon-for-all/312-days-in-the-stratosphere-

If you want to DF without RF - 130 dB ought to be easy with one of these... Before Radar, How Were Air Attacks Detected? With old time hearing aids! STRANGE ACOUSTIC "EARS" BEFORE RADAR - ON A SWIVEL

Listening to the scanner, the responders were told to be cautious of the envelope and anything silver as it may have a 10,000 volt charge on it. Apparently some part of the science experiment that the