This circuit was found in Radio Electronics magazine from June 1958. The maximum distance depends on cable losses. More stations can be added.
We find this circuit in a radio amateur publication of 1977. Its purpose is to measure the...
This inverter amplifier is from a 1992 publication. NPN transistors can be BC548 and PNP BC558....
I found this circuit in a 1986 English magazine. It can still be easily assembled, exchanging Q1...