The SPST switches are antennas. The oscillator on the left is a simple oscillator with very low gain to disturb the frequency of the oscillations as little as possible. The SPDT switch is for the user to switch to transmit morse (or other) code. On the left is an extremely high-Q band-pass filter. It accepts the transmitted signal but not the noise because it accepts a very narrow band of frequencies (noise becomes more and more the wider the band. In fact noise received is directly proportional to bandwidth) because of the high-Q. As a consequence of this it will change state between receiving a one or a zero very slowly compared to the radio wave period. This, however, shouldn’t be a problem if radio waves in the hundreds of thousands (or higher) of Hz are used and the transmissions are done by hand (few Hz max). This theoretically let’s morse code be transmitted across oceans and through thunderstorms by small battery powered tabletop transmitters if the right receiver is used. Also, the filters should be controlled not by inaccurate (by this thing’s standards) LC circuits, but by piezoelectric circuits, optimally in a temperature controlled environment for maximum precision.
