This power supply circuit for high power audio amplifiers was found in Radio Electronics from the 90's. Power MOSFETs admit modern equivalents. The output current is 5 A.
This antenna for the frequencies 146 or 440 MHz was found in a magazine 73 for Amateur Radio of...
We found this circuit in an 80's EDN. The circuit makes use of a MAX680, being given a table with...
This circuit was found in a 1986 publication. However, it can still be easily assembled, as the...