A bunch of alternating tones..
From Signal Identification Wiki
|Location||Southeast Allentown, PA|
|Short Description||I found this while scanning around the military air band with my SDR, and about midway through the audio file, you can hear something that sounds like a modem, very odd. There are also more than one of them on the band, on several different frequencies. Never heard anything like it.|
|I/Q Raw Recording||Download file|
No Audio File