From Steven, G7VFY comes news of a very simple 10m DSB transmitter from the blog of KA7OEI. This is an experimental very low power transmitter. It is unlikely to be of use in serious applications, but the range might surprise some. On 10m, the antenna is efficient and on a clear frequency it has the potential to get a long way. Over 1000km would not surprise me on a totally clear frequency. After all, 1mW (or so) is about 53 if a 100W signal was 59+12dB. On 10m such signals with 100W are very possible.
See http://ka7oei.blogspot.co.uk/2014/10/the-pointless-10-meter-dsb-qrp.html .