Question E1D12:
[97.207(e), 97.203(g)] Which of the following amateur stations may transmit one-way communications?  

Choices:  
A: A space station, beacon station, or telecommand station  
B: A local repeater or linked repeater station  
C: A message forwarding station or automatically controlled digital station  
D: All these choices are correct    

Correct Answer is  A: A space station, beacon station, or telecommand station  

To the point: Part 97 generally prohibits one-way transmissions except where specifically allowed. The three station types explicitly permitted to transmit one-way are space, beacon, and telecommand.

Why A is correct
- Space station (97.207[e]): May transmit one-way communications (e.g., downlinks, telemetry).
- Beacon station (97.203[g]): By definition, a beacon transmits one-way signals to indicate propagation.
- Telecommand station (97.3 and 97.111[b], 97.215): Telecommand is one-way control of a device or station (e.g., model craft control, remote station control).

Why the others are incorrect
- Local or linked repeater (97.205): Repeaters are intended for two-way relaying; they are not a class generally authorized for one-way transmissions (beyond required ID/telemetry, which is not the broad “one-way communications” the question targets).
- Message forwarding or automatically controlled digital station (97.219, 97.221): These support two-way data exchange/forwarding; they are not generally authorized for one-way transmissions.

Useful rules of thumb
- Memory tip: S-B-T = Space, Beacon, Telecommand → allowed one-way.
- Also allowed one-way by rule (not asked here): code practice and information bulletins (97.111[b]); these are types of transmissions, not station classes.