The relays are used to select one of the crystal filters. The easiest to use would be SPDT relays, but two SPST relays might provide better isolation between the filters. A second filter could be switched into a one filter strip, which would simplify the circuit a lot. This layout was just the way it happened when I built the receiver, but it could be simplied. |
Send E-Mail || Amateur Radio Receivers || Super Receiver || Super Receiver Circuit Details