Frequency is the number of cycles a periodic wave completes each second, measured
in hertz (Hz).1 For a radio wave it is the quantity you
tune to, and it is inversely related to wavelength.
Frequency is how many cycles pass each second; higher frequency packs more cycles into the same time (and means a shorter wavelength).
How it works
One hertz is one cycle per second. Radio frequencies are large, so they are scaled in
kilohertz (kHz), megahertz (MHz), and gigahertz (GHz). Because all radio waves travel
at the speed of light c, frequency and wavelength satisfy wavelength = c /
frequency.
Relevance to SDR
Tuning an SDR sets the centre frequency its local oscillator
mixes down to baseband. The chosen frequency, within a band,
determines what signal you receive.
Sources
Frequency — Wikipedia, definition, the hertz unit, and the relationship to period and wavelength. ↩
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