What is the approximate SWR value above which the protection circuits in most solid-state transmitters begin to reduce transmitter power?

The correct answer reflects the typical threshold for standing wave ratio (SWR) at which solid-state transmitters activate their protection circuits to prevent damage. SWR is a measure of how effectively radio wave energy is transmitted through a system, and high SWR values indicate poor matching between the transmitter and the antenna.

When the SWR exceeds approximately 2 to 1, many solid-state transmitters begin to detect the imbalance and will reduce their output power. This condition helps protect the transmitter from excessive heat and potential damage caused by reflected power that can occur when the load is not well matched. Maintaining a lower SWR ensures efficient power transfer and minimizes stress on the equipment.

The other values listed, such as 1 to 2, 6 to 1, and 10 to 1, either indicate conditions that fall well within safe operational limits or represent scenarios where the transmitter may be exposed to harmful levels of reflected power for an extended period.