1950 grid dip meter. The diagram is divided into two parts in case the builder wants to place the power supply in one chassis and the RF portion in another. It is the builder's option as to whether to put the entire meter in one chassis or two. Although the connections between the two sections are not numbered in the print diagram they will be referred to by numbers here to avoid confusion. One prong of a two prong power plug goes to the bottom end of the primary of a power transformer, see text. The other prong goes through a switch then a fuse to the top of the primary. One side of the 6.3 volt heater winding connects to chassis and also to connection point 3. The chassis ground from the power supply connects to connection point 2. One side of the 120 volt secondary goes to chassis ground. The other side goes to the anode of a rectifier, updated to a 1N4007 silicon diode. The cathode of the diode goes to the positive side of a 22 u f 250 volt capacitor. The negative side goes to chassis ground. The diode cathode also goes to the clockwise end of a 100 k ohm pot. The other side goes to chassis ground. The wiper of the pot goes to connection point 1. Connection point 4 goes to the negative side of a 1 m A meter. The positive side goes to chassis ground. This completes the power supply and metering chassis.

On the RF side connection point 1 goes to one side of a 0.01 u f capacitor. The other side connects to chassis ground. The chassis ground goes to connection point 2. Connection point 1 also goes to one end of a 1 k ohm resistor. The other end goes to the plate of the tube, 955. The plate also goes to one side of a 100 p f capacitor. The other end goes to the top stator of a split stator variable capacitor. See note at end of description. The capacitor is labeled 42 p f each section. The junction of the fixed and variable capacitor goes to pin 1 of a connector socket. Pin 1 of the mating plug goes to the top end of a coil. This represents the coils that are plugged in to select the frequency range. The other end of the coil goes to pin 2 of the connector plug. Pin 2 of the socket goes to the bottom stator of the split stator variable capacitor. The rotor is grounded to the chassis. The bottom stator also goes through a 100 p f capacitor to the grid of the tube. The grid of the tube connects to one end of a 22 k ohm resistor. The other end of this resistor goes to connection point 4. Connection point 4 is also bypassed to chassis ground through a 0.01 u f capacitor. The cathode and one side of the tube's heater go to chassis ground. The other side of the heater is bypassed to chassis through a 0.01 u f capacitor. This side of the heater goes to connection point 3. This completes the description of the schematic diagram.

Note. A split stator capacitor is really nothing more than two variables, usually of the same capacitance, on a single shaft so they turn together. The two rotors are electrically connected together by the metal shaft. The two stators are electrically insulated from each other and from the frame of the capacitor. Such a variable capacitor can be used either to tune two separate resonant circuits or as a center tapped capacitor as in the circuit described above. End of note and end of verbal description.
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