Tune it by the numbers, then tune it by ear.
Antenna lengths, SWR and return loss, coax loss, stub lengths, dBm and S-units, and free-space path loss, worked out the way an amateur radio operator does. Every calculation runs in your browser.
Dipole Antenna Calculator
Find the cutting length of a half-wave dipole, a quarter-wave vertical or a full-wave loop for any frequency, with leg and radial lengths.
Open → 1.5 : 1SWR Calculator
Convert between forward and reflected power, SWR, reflection coefficient, return loss and mismatch loss, or find the SWR of a load impedance.
Open → −1.54 dBCoax Loss Calculator
Estimate how much power a coaxial feed-line loses at a given frequency and length, including the extra loss from SWR at the antenna.
Open → ¼λ × VFCoax Stub & Electrical Length Calculator
Work out the physical length of a quarter-wave, half-wave or longer coax section from the frequency and velocity factor, or the electrical length of a cable you have.
Open → 100 W = 50 dBmdBm & Power Converter
Convert between watts, dBm and dBW, find the voltage across 50 Ω, turn an S-meter reading into dBm and apply gains or losses in decibels.
Open → FSPL 105.3 dBFree Space Path Loss Calculator
Calculate free-space path loss for a distance and frequency, and build a simple link budget from power, antenna gains, losses and receiver sensitivity.
Open →Lengths and losses are starting points from handbook formulas and typical cable data; measure your own installation. Transmitting requires a licence, and you are responsible for your band privileges, RF exposure and safety around power lines and towers.