This circuit is from an American documentation from 1975. The circuit uses components of the time which can be replaced by modern equivalents. The coupler is homemade with a lamp and a photocell.
This powerful amplifier with 2N3055 transistors at the output provides a few tens of watts rms on a...
With this circuit it is possible to receive and send audio signals simultaneously over the same...
This circuit generates 100 MHz signals from a 20 kHz crystal. The circuit is from an 80's...