FM Dipole Antenna Calculator
Cut a wire dipole for your favourite FM station — ~1.45 m total at 98 MHz, the classic 75 Ω T-dipole, and why height and orientation beat length tweaks.
Preset: half-wave dipole at 98 MHz (band centre) → 1.45 m total, 72.7 cm per leg, fed in the middle with 75 Ω coax. For one favourite station, enter its exact frequency and re-cut.
FM Dipole Antenna Calculator computes half-wave dipole lengths for FM broadcast (88–108 MHz) — the classic T-shaped twin-lead antenna — free, instant and private in your browser. Radio listeners, tuner restorers and SDR hobbyists cutting wire dipoles use it to skip the datasheet algebra: type your numbers, read the answer with the substituted formula shown step by step, and share an exact permalink of the calculation.
About FM Dipole Antenna Calculator
FM Dipole Antenna Calculator computes half-wave dipole lengths for FM broadcast (88–108 MHz) — the classic T-shaped twin-lead antenna using the standard engineering relation: L = 0.5·(c/f)·k → 1.45 m total at 98 MHz, 72.7 cm per leg. Worked live: for one weak favourite at 101.3 MHz, a dedicated 1.41 m dipole beats the generic band-centre cut audibly. The result recalculates on every keystroke, the worked-example panel shows your numbers substituted into the formula, and the Copy permalink button encodes the inputs in the URL so a colleague opens exactly your calculation. Everything runs client-side — nothing you type leaves your device.
How to use FM Dipole Antenna Calculator
- 1Enter your values — the tool starts with realistic defaults for this exact use case, so the worked example is meaningful immediately.
- 2Read the live result and the worked-example panel, which substitutes your numbers into the formula step by step.
- 3Adjust any input to compare scenarios, then use Copy result or Copy permalink to share the calculation.
Why use FM Dipole Antenna Calculator?
- ✓Implements the real formula — L = 0.5·(c/f)·k → 1.45 m total at 98 MHz, 72.7 cm per leg — with the substitution shown, not a black box
- ✓Built for radio listeners, tuner restorers and SDR hobbyists cutting wire dipoles
- ✓Copy result and permalink buttons — share the exact calculation in a README, forum answer or design review
- ✓100% free, no sign-up, runs entirely in your browser (works offline once loaded)
Frequently asked questions
How do you calculate fm dipole antenna?+
Half-wave dipole lengths for FM broadcast (88–108 MHz) — the classic T-shaped twin-lead antenna follows L = 0.5·(c/f)·k → 1.45 m total at 98 MHz, 72.7 cm per leg. For example, for one weak favourite at 101.3 MHz, a dedicated 1.41 m dipole beats the generic band-centre cut audibly. The calculator applies the same relation and shows the substituted arithmetic so you can verify every step.
Why are FM antenna inputs 75 Ω?+
Because the antenna chose it: a half-wave dipole's natural feedpoint impedance is ~73 Ω, so receivers and the classic flat twin-lead standardised on 75 Ω for a no-tuner match. Cheap RG-6 satellite coax is therefore the perfect FM feedline — better shielded than vintage twin-lead and immune to rain and gutter contact.
Where should I hang an indoor FM dipole?+
High, stretched fully open, and away from mains wiring and metal. The dipole receives best broadside (the flat side faces the transmitter) and is deaf off its tips — rotating a weak station into the broadside lobe is often worth more than any amplifier. If the station is vertically polarised (many translators are), try the dipole vertical.
Is the FM Dipole Antenna Calculator free and private?+
Yes — completely free with no sign-up or usage limits, and it runs entirely in your browser: the values you enter are never uploaded or stored on a server.
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