We found this circuit in a documentation from the 90's. The coil has its characteristics given next to the diagram. Power is provided by a 9 V battery and a range of a few tens of meters.
Suggested for use in cars and motorcycles, this circuit was found in a 90s Popular Electronics. The...
This is a typical 3 ½ digit TTL counter. We found it in the September 1973 issue of Radio...
This receiver, whose tuning range depends on L1 and L2, was found in the 1992 special edition of...