Signals & radio calculator
Wavelength & frequency
A wave travels c metres a second; each of its f cycles is c / f long.
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The example, worked out
Given
- I know
- The frequency
- Frequency
- 2.4 GHz
- Velocity factor
- 1
Working
- at the speed of light
- one cycle
Results
The formulas
- λ = v / f = c × vf / fslower in a cable, so shorter
- quarter-wave whip ≈ 0.95 × λ / 4a little shorter for the end effect
The usual traps
- Using c in a coaxial cable: the wave goes at 66 % of it.
- A trace longer than λ/10 behaves as a transmission line.
Questions
How do I calculate the wavelength of a frequency?
λ = v / f = c × vf / f: slower in a cable, so shorter. quarter-wave whip ≈ 0.95 × λ / 4: a little shorter for the end effect.
What does it give for typical values?
2.4 GHz ↔ λ = 125 mm. Wavelength λ: 125 mm.
What are the usual mistakes?
Using c in a coaxial cable: the wave goes at 66 % of it. A trace longer than λ/10 behaves as a transmission line.
In the app
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The part you can buy
Results rounded to standard values (E12, E24, E96) and power ratings.
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Open the calculatorOpens in the app on 1 December, with Circuit Notebook 1.0
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