This circuit was found in a 70s documentation. The transistor is from that time. L1 has 4 turns of wire 20 in the form of 3/32 inches and L1 has 10 turns of the same wire,
The transistors are 2N918, 2N3464 and other RF equivalents of the time for Q1. For Q2, 2N3399, 2N2894...
This circuit, which can be used as a shield, was found in a 90s Electronic Design. The circuit...
This interesting intercom circuit was obtained from an Argentine publication from the 1970s....