Upper frequency limit for existing coax systems?

• A. 450 MHz
• B. 750 MHz
• C. 500 MHz
• D. 1000 MHz

Answer: (B)

The key idea is how far an existing coax can reliably carry signals before losses and signal distortion undermine performance. In typical outside-plant coax installations, attenuation and impedance tolerance worsen with frequency, so there’s a practical ceiling where you can still meet required link specs using standard connectors and terminations. That ceiling is about 750 MHz, which is why this value is used as the practical upper limit for existing coax systems. Pushing toward 1 GHz would usually require upgrading to higher-quality coax or replacing the infrastructure, while lower values would undervalue what many installed cables can support.