Question 3-81L1

Marine SSB (Single Sideband) transceivers are designed for power efficiency by suppressing the carrier signal and transmitting only one sideband. In normal SSB operation, RF power is only generated when voice or other modulation is applied to the microphone input. Therefore, if you key an SSB transmitter without speaking into the microphone, there should ideally be no RF output power whatsoever. A steady output of 75 watts indicates that the carrier suppression circuit has failed, and the transceiver is transmitting a significant portion of its carrier power even without modulation. This is a defect in the system. * **A) There is probably a defect in the system causing the carrier to be transmitted.** This is correct. The unwanted presence of a steady carrier signal is a fault. * **B) One of the sidebands is missing.** This statement describes normal SSB operation, where one sideband is intentionally suppressed along with the carrier. It does not explain a steady power output. * **C) Both sidebands are being transmitted.** If both sidebands *and* the carrier were transmitted, it would be Amplitude Modulation (AM), not SSB. While some specialized modes transmit both sidebands without a carrier, a steady output implies a carrier. * **D) The operation is normal.** This is incorrect. Normal SSB operation produces no RF output power without modulation.