Now a word to my fellow blind tube techies. This diagram includes the part that was in the first lesson. Each lesson will add a little to the existing diagram. By the time we get to the end of this series it could get pretty repetitive. Below each schematic there will be two links. One will be just the parts added in the current lesson. The second link will be the complete diagram. You can take your choice.

The converter. On the left is a tuned loop antenna. It is an inductor which has been wound big so it can pick up the magnetic field of the radio waves. The top of the antenna goes to grid 3 of the converter tube. The top of the antenna also goes through one section of the tuning cap to ground. The bottom end of the antenna goes to a point labeled AGC. This point goes through a .1 mike cap to ground. The cathode of the converter tube goes to the tap on the oscillator coil. The bottom of the coil is grounded and the top goes through a 220 pf cap to grid 1 of the converter. Grid 1 also goes through a 22 k ohm res to ground. The coil is tuned by the other section of the tuning cap. Grids 2 and 4 of the converter tube are connected together inside the tube and are brought out to a single pin. This pin connects through a .01 mike cap to ground. This pin also goes through a 1 k ohm res to low current B plus. This same pin also connects to the low end of the primary of the first i f can. The high side connects to the plate. In the octal tube grid 5 is brought out to a separate pin and this pin is grounded. In 7 pin mini tubes grid 5 connects to the cathode inside the tube. The high end of the i f secondary connects to the control grid of the i f amplifier tube. That's all for this lesson. End verbal description.
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