This is a push-pull, crystal-controlled, two-tube, 5 meter transmitter, designed by RCA in about 1935. It uses two 807s in this circuit, but could easily be adapted to use nearly any beam-tetrode, i.e. 6146, 6L6, 813, etc. It is supposed to be VERY easy on crystals, although the screen voltage must be watched carefully. This transmitter is also an RCA re-design of the Jones rig. Interesting.