One of my motivations for building and Arduino controlled DDS-60 was to use it as the VFO for a QRP transmitter. I have had success with this by using the RF stages of the Universal QRP Transmitter Mk-II by Wes Hayward W7ZOI as described in QST April 2006. Click here to download the article for free from the ARRL.
I've been having fun with QRSS over the last few weeks. My Arduino controlled DDS-60 has been transmitting "barefoot". i.e, connected directly to an antenna tuner which goes to a balun which feeds the ladder line out to my antenna. It's been running for long periods sending very slow CW using frequency shift keying with about 6 Hz shift.
A recent project has been the building of a digital VFO based around the DDS-60 kit and Arduino controller. It's a useful thing to have either as part of a homebrew transmitter or transceiver or as a piece of test equipment. It can generate RF from 1 to 60 MHz in 1 Hz steps with the stability of a crystal oscillator and can run as a QRSS beacon. It's nothing particularly original and it's not rocket science but it might be helpful for someone wanting to get started with DDS and microcontrollers. It's still a work in progress and I'll be happy if anyone wants to contribute ideas or discussion.