WSPR Beacon

Features:
* Sends WSPR transmissions
* Can run in the background
* Let's the device sleep between transmissions (to save battery)
* Time is synced with NTP.
* Can send compound callsigns and 6-digit locators (requires 2 transmission cycles)
* Can be used to check WSPRNET for spots.

Caution:
You need an amateur radio license or be doing some experiments for this app to be useful to you.
Always monitor your transmissions. The author of the app is not responsible for your transmissions.