Question
Why is it important to know the duty cycle of the mode you are using when transmitting?
Answer Options
- A) To aid in tuning your transmitter
- B) Some modes have high duty cycles that could exceed the transmitter’s average power rating
- C) To allow time for the other station to break in during a transmission
- D) To prevent overmodulation
Correct Answer: B
Explanation
The duty cycle of a mode is the percentage of time during a transmission that the RF energy is actually at its peak power level. Voice (SSB) has a low duty cycle (around 20\%), while constant carrier modes like CW and FM have a high duty cycle (50\% to 100\%).
It is critical to know the duty cycle because some modes have high duty cycles that could exceed the transmitter’s average power rating. Transmitting a constant carrier at the maximum peak power for an extended period can quickly cause the final amplifier to overheat and fail, so the transmitter’s power must be reduced for high duty cycle modes like FM and RTTY to protect the equipment.
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