This simple, unregulated power supply with an approximate 6 V output voltage can supply currents up to about 500 mA depending on the transformer. The diodes can be 1N4002.
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...