I am trying to build a mobile RF amp, and so far the schematics I have found are for base stations using 120v or 220v mains. I need to be able to produce a bi-polar power supply that gives me +- 50-70v dc from 12-13vdc. Any ideas will be helpful. Commonly available parts at reasonable cost would be appreciated. Schematics for a Solid State 100W CB linear amp would make me very happy also! Thanks DougTee