[Hallicrafters] SR-400A on CW

[Jim Liles]

Good morning Don: 
The SR-400A generates CW using the upper sideband crystal.  It transmits and receives on the same frequency but generates an artificial transmit tone at about 800 to 900 Hz.  The best way to make it very close to exact is to tune a cw signal so that you are comfortable with the pitch and then alter the transmit sidetone generator circuit for the same note.  Kindest regards Jim K9AXN