Question T5B12
From subelement T5 - T5B
Which is equal to 28400 kHz?
Why is this correct?
28400 kHz equals 28.400 MHz because kHz (kilohertz) and MHz (megahertz) differ by a factor of 1000. Since mega means million and kilo means thousand, 1 MHz = 1000 kHz. To convert from kHz to MHz, divide by 1000: 28400 ÷ 1000 = 28.400 MHz. Choice A repeats the original value, while choices B and C show incorrect decimal placement from miscalculating the conversion factor.
Memory tip
When converting between frequency units, move the decimal point based on the prefix difference. From kHz to MHz, move three places left (÷1000). From MHz to GHz, move three places left again. This systematic approach prevents conversion errors across all frequency ranges.
Learn more
Frequency conversions are critical in amateur radio because different bands are specified in different units. The 10-meter band spans 28.000-29.700 MHz, while shortwave listeners might reference the same frequencies as 28000-29700 kHz. Transceivers typically display frequencies in the most appropriate unit for the band, but understanding conversions helps when referencing band plans, calculating antenna dimensions, or interpreting technical specifications that may use different units.
Think about it
Why do you think amateur radio references use different frequency units (kHz, MHz, GHz) for different bands rather than standardizing on one unit?