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.

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Last Update: 12-20-2002
Web Author: David White, WN5Y