Digisonde
From Signal Identification Wiki
Digisondes are ionosondes that use pulsed signal that can gather more radar information than a traditional ionosonde sweep. It is sometimes called "The Grinder" by amateur operators.
The specifications of the Digisonde transmitters can be found here on the manufacture's website. A map of all the Digisonde locations can be found on their main page.
Video Examples[edit]
Digisonde "Grinder", October 05, 2012, 1501 UTC, 4700 kHz