When using a VOR Test Station (VOT), what should the CDI and OBS be set to?

When using a VOR Test Station (VOT) for checking the accuracy of a VOR receiver, the Course Deviation Indicator (CDI) should be set to 360 degrees FROM. This means that the VOR receiver is set to indicate a bearing of 360 degrees relative to the VOT, which is the reference used during the test.

In this scenario, selecting 360 degrees FROM allows the pilot to confirm that the VOR is accurately indicating the correct radial and that the needle is centered when the heading matches the reference. When at the VOT, the aircraft is effectively on the "360-degree radial" of the VOT, which ensures that any deviations in the VOR system can be accurately assessed.

Utilizing this setting confirms that the VOR receiver is functioning correctly according to the standard requirement for testing VOR systems. The other options do not provide the correct reference for verifying the VOR's accuracy when using a VOT, as they either indicate a different radial or an incorrect method for testing the receiver.