Trust Doc Searls to know more than most of the rest of us will ever dream that there is to know about FM radio. In a long, intricate explanation of FM signal strength, Doc unveils the clue to getting those low-power FM transmitters-for-your-portable-music device to work: “Make the antenna longer by adding a headphone extention cord: female at one end and male at the other. Put it between your audio player (iPod, Archos or whatever) and your transmitter. Stretch it out. The signal increase is remarkable.” Dave Winer attests, “It works.” Si has one of those gadgets; we’ll test it and see, but this sounds intensely helpful.