Question
On what HF frequencies are automatically controlled beacons permitted?
Answer Options
- A) On any frequency if power is less than 1 watt
- B) On any frequency if transmissions are in Morse code
- C) 21.08 MHz to 21.09 MHz
- D) 28.20 MHz to 28.30 MHz
Correct Answer: D
Explanation
Automatically controlled beacon stations on the HF bands are restricted to specific, narrow frequency segments to minimize interference. On the 10\text{-meter} band, FCC Rule \S 97.203(\text{d}) specifies the range 28.20 \text{MHz} to 28.30 \text{MHz} for automatically controlled beacons. This is the only segment on the HF bands where such operation is permitted.
This specific frequency allocation helps to centralize the propagation observation activity, making it easy for operators to know where to listen for beacons. While beacon operations may exist elsewhere, they are not allowed on any frequency below 28.20 \text{MHz} on HF for automatically controlled stations.
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