Several have asked how I powered the little imported frequency counter board on my Navy RAS receiver mod. One suggestion was just use a Wall Wart. Last night I cobbled together a voltage doubler circuit and used the 6.3 volts AC present above chassis on the RAS receiver pilot light socket.
The doubler circuit utilizes a full wave rectifier as suggested by Al N3FRQ to reduce ripple.  Not many parts just two Caps and a little IC rectifier and a resistor.  I did fabricate a standard "snap" connector  mounted on the board. The frequency counter board  will then use a standard 9 volt connector. Plenty of room on the receiver chassis for the 1.5 X 2 inch board.
Anybody got any National knobs or tube shields?
Z