Ham Radio Tools by IU2FRL
A collection of tools for amateur radio enthusiasts.
Dipole Length Optimizer
Compare current resonance vs target resonance and get CUT/ADD guidance, including quarter-wave and three-quarter-wave scenarios.
Antenna Sizing Tool
Enter one target frequency and calculate recommended element lengths in metric and feet.
Maidenhead Locator Tool
Convert between latitude/longitude and grid squares. Calculate distance and bearing between locations.
Coax Loss Calculator
Calculate feedline loss by cable type, frequency, and length. Find power at antenna and dissipation in cable.
Coax Filter Designer
Design notch and bandpass filters using coaxial transmission lines. Calculate stub lengths by frequency.
Matching Network Helper
Calculate impedance transformation ratios for common network types (1:1, 4:1, 9:1).
Loading Coil Calculator
Calculate inductance and turns needed to shorten antenna elements for a given frequency.
Balun and Choke Reference
Quick reference for ferrite core selection and winding recommendations by frequency and power.
Portable Ops Toolkit
End-fed wire lengths and counterpoise recommendations per band. Perfect for field operations.
APRS Passcode Generator
Generate your passcode for connecting to the APRS-IS network. Required for IGate operations.