Secure wireless networks

We all know how easy it is for anyone to drive into our neighborhood and hack into our wireless networks within minutes using freely available programs on the internet. I suggest that we have our networks hop passphrases. The transmitters and receivers are given a passphrase database and hop schedule via USB so that they all hop to the same passphrases at the same times several times per second. Eavesdroppers will have no idea when the passphrases change, when they will be used again, or that they are changing, except that as they attempt to assemble the passphrase, the pieces change. They will be unable to listen long enough to determine any complete passphrase, or even if they did, to use it for more than a split-second, literally.