🔍 Key Concepts

• Parts per million (ppm) as a way to express frequency tolerance • How to convert MHz to kHz and apply a 5 ppm tolerance range • Comparing each option’s frequencies to the nominal channel frequencies (156.875 MHz and 157.200 MHz)

💭 Think About

• What is 5 ppm of 156.875 MHz and of 157.200 MHz when expressed in kHz? • Once you know the allowed +/- range in kHz for each frequency, which of the proposed values fall inside that range? • Are the differences between the nominal frequency and each choice’s frequency smaller than, equal to, or larger than the allowed 5 ppm window?

✅ Before You Answer

• Convert both nominal frequencies from MHz to kHz correctly before doing ppm math • Compute 5 ppm × nominal frequency using consistent units (all in Hz or all in kHz) • For each choice, find the difference from the nominal and check whether it is less than or equal to the allowed tolerance in kHz