What antenna calculators are included?

The suite includes calculators for half-wave dipole, quarter-wave vertical, full-wave loop, end-fed half-wave, Yagi beam antennas, and wavelength conversions.

How does the coax cable loss calculator work?

The coax loss calculator uses manufacturer specifications for over 35 cable types. Enter cable type, length, and frequency to see total loss in dB.

Can I look up callsigns?

Yes! The callsign lookup uses free public APIs (HamDB and Callook) for US and international callsigns.

What propagation data is available?

The propagation panel shows information about Solar Flux Index, A-Index, K-Index, and band conditions with links to live data sources.

Which countries band plans are supported?

Band plans for USA, EU, UK, Japan, Australia, Canada, Germany, France, and IARU Regions 1, 2, and 3 are included.

📡 Ham Radio Calculator Suite

Comprehensive tools for amateur radio operators — antenna design, propagation, callsign lookup, and more

📻 Welcome, Radio Amateur!

This free tool suite includes antenna calculators (dipole, vertical, Yagi, loop, end-fed), coax cable loss analysis, SWR/return loss conversion, power conversions, Ohm's Law, LC resonant circuits, resistor color codes, great circle distance/bearing, decibel calculations, worldwide band plans, callsign lookup, and propagation data. Select a tab below to get started.

📐 Antenna Calculators

Metric Imperial

Antenna Calculator Help: Enter the desired frequency to calculate antenna dimensions. Uses standard formulas with 95% velocity factor. Half-wave dipole: 468/f(MHz) feet. Quarter-wave vertical: 234/f(MHz) feet. Full-wave loop: 1005/f(MHz) feet circumference.

Operating Frequency (MHz)

Antenna Type

📏 Coax Cable Loss Calculator

Meters Feet

Coax Loss Calculator Help: Uses manufacturer-specified loss values. Database includes 35+ cable types from RG-58 to Heliax. Loss is interpolated for your specific frequency.

Cable Type

Cable Length (meters)

Frequency (MHz)

Transmit Power (Watts)

Cable Specifications

Select a cable type to see specifications

📊 SWR & Return Loss Calculator

SWR/Return Loss Help: Convert between SWR, Return Loss, and Reflection Coefficient. Perfect match = SWR 1:1 or infinite return loss.

Input Type

SWR (:1)

Reference Impedance (Ω)

Transmit Power (Watts)

⚡ Power Conversions

Power Help: Convert between Watts, dBm, dBW. Calculate ERP (Effective Radiated Power) and EIRP based on antenna gain. ERP uses dipole reference; EIRP uses isotropic (2.15 dB higher).

Power (Watts)

Antenna Gain (dBi)

Feedline Loss (dB)

Ω Ohm's Law Calculator

Ohm's Law: Enter any two values to calculate the others. V = I × R, P = V × I = I²R = V²/R

Voltage (V)

Current (A)

Resistance (Ω)

Power (W)

〰️ LC Resonant Circuit Calculator

LC Circuit: Calculate resonant frequency, or find required L or C for a target frequency. f = 1/(2π√LC). Q factor indicates selectivity; higher Q = narrower bandwidth.

Calculate

Frequency (MHz)

Inductance (μH)

Capacitance (pF)

Q Factor

🎨 Resistor Color Code Calculator

Resistor Colors: Decode 4/5/6-band resistor codes or encode a value to colors. 4-band: 1st, 2nd digit, multiplier, tolerance. 5-band adds 3rd digit. 6-band adds temperature coefficient.

Mode

Number of Bands

🌍 Great Circle Distance & Bearing

km miles

Distance Calculator: Calculate great circle distance and beam heading using Haversine formula. Enter coordinates or grid squares (Maidenhead locator).

Your Location

Input Type

Grid Square

Target Location

Input Type

Grid Square

📈 Decibel Calculator

Decibel Calculator: Convert between linear ratios and dB. Power: dB = 10 × log₁₀(ratio). Voltage: dB = 20 × log₁₀(ratio). Add/subtract dB values properly.

Calculation Type

Type

Ratio

Decibels (dB)

Quick Reference

dB	Power Ratio	Voltage Ratio	Meaning

📋 Amateur Radio Band Plans

Band Plan Help: Browse frequency allocations by region and band. Verify with your local regulatory authority for current regulations.

Region	Band	Frequency Range	Modes	License	Notes
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🔍 Callsign Lookup

Callsign Lookup: Enter any callsign to look up operator information. Uses free public APIs (HamDB and Callook). US and many international callsigns supported.

🔍

☀️ Solar & Propagation Data

Propagation Help: Solar data affects HF propagation. Higher SFI = better high-band conditions. Lower K/A-index = quieter geomagnetic conditions = better propagation.

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