What are some measures that can be taken to prevent high VSWR in transmitters and receivers?

What are some measures that can be taken to prevent high VSWR in transmitters and receivers?

• A. Increase transmitter power.
• B. Shorten the cable length.
• C. Tighten connections between cables and connectors and use impedance-matched hardware throughout.
• D. Disable impedance matching.

Answer: (C)

Minimizing reflections in the RF path is what this item tests. When the load presented to a transmitter doesn’t match the transmitter’s output impedance, part of the power reflects back toward the source. Those reflections form standing waves, reduce the power actually delivered to the antenna, lower efficiency, and can even stress or damage transmitter stages. The best way to prevent high VSWR is to keep a clean, matched path from transmitter to antenna. Tightening connections between cables and connectors eliminates loose or corroded joints that introduce impedance irregularities at interfaces. Using impedance-matched hardware throughout—everything designed for the same system impedance (commonly 50 ohms in many RF setups)—preserves the characteristic impedance across cables, adapters, and the antenna. When the impedance is consistent, most of the power is radiated rather than reflected, keeping the VSWR close to 1:1. Increasing transmitter power won’t fix a mismatch; it simply increases the risk of damage if reflections rise. Shortening the cable length doesn’t reliably fix a mismatch either, since the magnitude of reflections depends on impedance, not just length, and length changes can shift where reflections appear but not necessarily reduce them. Disabling impedance matching would make mismatches worse and push the VSWR higher. Monitoring with an SWR meter can help verify that the system remains well-matched.

Minimizing reflections in the RF path is what this item tests. When the load presented to a transmitter doesn’t match the transmitter’s output impedance, part of the power reflects back toward the source. Those reflections form standing waves, reduce the power actually delivered to the antenna, lower efficiency, and can even stress or damage transmitter stages.

The best way to prevent high VSWR is to keep a clean, matched path from transmitter to antenna. Tightening connections between cables and connectors eliminates loose or corroded joints that introduce impedance irregularities at interfaces. Using impedance-matched hardware throughout—everything designed for the same system impedance (commonly 50 ohms in many RF setups)—preserves the characteristic impedance across cables, adapters, and the antenna. When the impedance is consistent, most of the power is radiated rather than reflected, keeping the VSWR close to 1:1.

Increasing transmitter power won’t fix a mismatch; it simply increases the risk of damage if reflections rise. Shortening the cable length doesn’t reliably fix a mismatch either, since the magnitude of reflections depends on impedance, not just length, and length changes can shift where reflections appear but not necessarily reduce them. Disabling impedance matching would make mismatches worse and push the VSWR higher. Monitoring with an SWR meter can help verify that the system remains well-matched.