Paolo, you can also generate a WSPR signal as "direct FSK". All you need is four tones with 12000/8192 = 1.4648Hz separation, a table holding the 162 message symbols and some proper timing. Each symbol (tone duration) is 8192/12000 = 682.66667ms. According to the WSPR documentation, the tone shifts should be phase continous, this is easily accomplished with a DDS or a simple VXCO.
Description of a PIC based WSPR beacon controller can be found here: http://web.telia.com/~u33233109/ It can be used with either an AD9850 DDS or a varicap tunes VCXO. 73 Johan SM6LKM Paolo Cravero wrote: > I've recently been intrigued by WSPR weak signal HF mode, and > immediately started thinking of a simple transmitter that would allow > me computerless beaconing.
