Just orderd a couple (2 versions) of WSPR mode add-on boards for the Raspberry Pi SBC from TAPR. A lot of acronyms in that sentence, but most radio amateurs will know what they are. WSPR is "Weak Signal Propagation Reporter". It is a very low power radio beacn listening system hoasted on the Internet. Here is a link to the WSPRnet website where more information can be discovered. http://wsprnet.org/drupal/
An accessory board usually called a shield for some obsure (to me) reason by SBC (Single Board Computers) enthusists, is plugged into a Raspberry Pi (RPi) computer to filter the harmonics from the RF signal generated within the computer. Yep, a synthetic sofware derived transmitter. Transmission timing and all the other necessory details like callsign, transmitted data, are handled by the Rpi.
Only a few miliwatts of power reach the antenna, but that is the entire point. It is a test system for very low powered transmission as well as a test of propagation conditions. Reception reports are logged to the WSPRnet website.
I am no expert at this point. In fact I admit to being very ignorant of this type of operation.
But that is the very essence of amateur radio. Trying and learning about new methods of radio communication.
I will create a new section (Category) on this website about my activities and results.