This question broaches, albeit only lightly, the topic of what are called "special operations". There are, in subpart C of the amateur radio regulations, a number of special ways to use, or operate, a radio station that are subject to special rules. These special rules typically impose certain restrictions while relaxing others. For example, an auxiliary station (the topic of this question) is an amateur station (other than a packet station) that is transmitting communications point-to-point within a system of cooperating amateur stations. Auxiliary stations are not permitted to operate on bands below 222 MHz, but are allowed to be automatically controlled (that is, no control operator at the control point). Auxiliary stations which have been coordinated also gain some extra protection against interference, and the general rule against one-way communications is relaxed for auxiliary stations.
T1A11: Which of the following stations transmits signals over the air from a remote receive site to a repeater for retransmission?
- Beacon station
- Relay station
- Auxiliary station
- Message forwarding station
The correct answer is C–Auxiliary station.
The most common use for auxiliary stations is in conjunction with a repeater station. Two linked repeaters may use a pair of auxiliary stations to establish the link, or a remote receiver may use an auxiliary station to connect back to the main transmitter. The W9DUP repeater, operated by the DuPage Amateur Radio Club (of which I am a member) uses an auxiliary station to connect its IRLP node to the repeater, since the IRLP computer cannot be placed at the repeater's location (no Internet access there).
There are several special operations listed in Subpart C, but this is the only one that the NCVEC Question Pool Committee saw fit to include on the Technician pool.