Solve radio frequencies using multiple inputs and units easily. Convert to wavelength, period, omega, and LC resonance. Share results with downloadable reports for teams.
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| Known input | Medium | Computed frequency | Medium wavelength | Quarter-wave |
|---|---|---|---|---|
| λ = 3 m | VF = 1.00 | ~ 99.931 MHz | 3.000 m | 0.750 m |
| T = 10 ns | VF = 0.66 | 100.000 MHz | ~ 1.979 m | ~ 0.495 m |
| L=100 nH, C=10 pF | VF = 1.00 | ~ 159.155 MHz | ~ 1.884 m | ~ 0.471 m |
Examples are indicative and depend on medium selection.
Wave velocity in medium
v = c / √(εr μr)
Or v = VF × c when using velocity factor.
Frequency relationships
f = v / λ
f = 1 / T
f = ω / (2π)
LC resonance
f = 1 / (2π √(LC))
Derived quantities
λ = v / f
β = 2π / λ
Quarter-wave = λ/4, Half-wave = λ/2
Radio-frequency work ties together frequency, wavelength, and timing. A 100 MHz signal has a 10 ns period and a free‑space wavelength near 3.0 m. These linked quantities help you size antennas, estimate line lengths, and sanity‑check oscilloscope timebases.
RF spans many orders of magnitude. Common reference points include 13.56 MHz (industrial/scientific/medical), 88–108 MHz (FM broadcast), 433 MHz and 915 MHz (short‑range devices), 2.4 GHz and 5 GHz (Wi‑Fi), and 28 GHz (mmWave). Converting everything to Hz internally avoids mistakes when mixing MHz and ns. Quick check: doubling frequency halves wavelength.
Inside cable or dielectric, wave velocity is lower than in vacuum. Using a velocity factor (VF) of 0.66 gives v≈0.66c, so wavelength shrinks by the same factor. At 100 MHz, λ in the cable is about 1.98 m instead of 3.00 m, which directly changes quarter‑wave and half‑wave cut lengths.
When VF is unknown, a simple model uses v=c/√(εrμr). Most non‑magnetic materials have μr≈1, so εr dominates. If εr=2.25, then VF≈1/√2.25≈0.667, close to many polyethylene‑based coax types. Use measured data when accuracy matters because effective εr depends on geometry.
Transmission‑line and antenna work often starts with fractions of wavelength. At 915 MHz in free space, λ≈0.328 m, so a quarter‑wave is about 82 mm. In a VF 0.80 cable, quarter‑wave becomes roughly 66 mm. These values guide first‑pass stubs, matching sections, and monopole estimates.
Some RF equations use ω and β instead of f and λ. The relationships ω=2πf and β=2π/λ keep the math consistent for sinusoidal steady state. For example, a 2.4 GHz signal has ω≈15.08×109 rad/s, and β depends on the medium wavelength you choose.
Resonant tanks, filters, and oscillators are often set by L and C using f=1/(2π√LC). With L=100 nH and C=10 pF, the resonance is near 159.15 MHz. Changing C to 22 pF moves resonance down to about 107.3 MHz, showing why small component shifts matter at RF. Parasitics can shift resonance further above VHF.
RF work benefits from traceable calculations. Exporting CSV supports quick comparison across variants, while the PDF summary is useful for build notes and test plans. Always confirm final designs using measured cable VF, real component tolerances, and application‑specific standards.
Signals travel slower in dielectric materials than in vacuum. The velocity factor reduces wave speed, so wavelength shortens by the same factor at the same frequency.
Use velocity factor if you have cable datasheet values or measurements. Use εr and μr when modeling a material; most dielectrics have μr close to one.
It is good for first‑pass estimates. Final cut lengths depend on end effects, nearby conductors, and insulation. Always trim and verify with measurements or simulation.
In many engineering contexts, RF covers roughly 3 kHz to 300 GHz. The same relationships still apply above and below, but component behavior changes.
Circuit and field equations often use ω because derivatives of sinusoids bring out ω. Converting between f and ω avoids mistakes when applying impedance and propagation formulas.
Because f depends on √(LC), small percentage changes in L or C shift resonance noticeably. At high frequencies, parasitics and layout inductance can dominate component nominal values.
No. β here is computed from wavelength in the selected medium model. Lossy lines require complex propagation constants and additional parameters such as attenuation.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.