What is the primary purpose of using a portable SWR bridge during field checks?

• A. To indicate standing wave ratio and assess antenna matching.
• B. To monitor battery temperature
• C. To measure radio's overall efficiency
• D. To tune modulation depth

Answer: (A)

The main idea is to verify how well the antenna is matched to the transmitter. A portable SWR bridge serves as a diagnostic that reveals the standing-wave ratio by comparing the forward power sent toward the antenna with the reflected power coming back from it. A low SWR means most of the transmitter’s energy is being radiated with little reflection, which protects the transmitter, reduces wasted power, and ensures the antenna is effectively tuned for the operating frequency. If the SWR is too high, you adjust the antenna length, loading, or matching components until the ratio drops to an acceptable level before transmitting.

This tool isn’t about battery temperature, overall transmitter efficiency, or modulation depth, which is why those other options don’t fit. The SWR bridge specifically targets the RF path between the radio and the antenna to confirm a proper match.