Amateur Radio Toolkit is the best app for ham radio hobbyists. It contains many calculators to help you design radios and antennas for all your projects. Tools: Q code - A list of common Q codes 92 Code - A list of common 92 codes RST code - A list of RST codes Coordinate calculator - Find your latitude and longitude by entering your maidenhead square. Grid square calculator - Find your maidenhead square by entering your latitude and longitude Distance calculator - Find the distance between two Maidenhead squares Unit converter - Convert between units Location - Find your location Dipole antenna - Calculate the optimal lengths of a dipole antenna for a given frequency Vertical antenna - Calculate the optimal lengths of a vertical antenna for a given frequency Cubical quad antenna - Calculate the optimal lengths of a cubical quad antenna for a given frequency Inverted Vee antenna - Calculate the optimal lengths of an inverted vee antenna for a given frequency Ground plane antenna - Calculate the optimal lengths of a ground plane antenna for a given frequency J pole antenna - Calculate the optimal lengths of a J pole antenna for a given frequency VSWR - Convert between VSWR, Refection coefficient, return loss and mismatch loss Three element Yagi antenna - Calculate the optimal lengths of a three-element Yagi antenna for a given frequency Seven-element Yagi antenna - Calculate the optimal lengths of a seven element Yagi antenna for a given frequency Wavelength frequency converter - Convert between wavelength and frequency Air core inductor - Calculate the inductance or lengths of an air core inductor Low pass filter - Calculate the units of an RC or RL LPF circuit High pass filter - Calculate the units of an RC or RL HPF circuit Ohm's law - Convert between voltage, current, resistance and power by entering two Reactance - Calculate the reactance of a capacitor or inductor Decibel calculator - Convert between decibel values or calculate dB by entering the power or voltage Voltage divider - Calculate the output voltage or resistance of one resistor Resistor Color codes - Find the resistance of a resistor by entering the colors of the bands Resistors in parallel - Calculate the resistance of resistors in parallel Resistors in series - Calculate the resistance of resistors in series Capacitors in parallel - Calculate the capacitance of capacitors in parallel Capacitors in series - Calculate the capacitance of capacitors in series Coaxial cable - Calculate the properties of a coaxial cable Morse code CW abbreviations NATO phonetic alphabet You can upgrade to the Pro version to remove all ads and get the following features: Half wave coax balun - Calculate the optimal length of a half wave coax balun for a given frequency Narrowband balun - Calculate the inductance and capacitance of a narrowband balun Small magnetic loop - Calculate the optimal lengths of a small magnetic loop for a given frequency Full wave loop antenna - Calculate the optimal lengths of a full wave loop antenna for a given frequency ERP and EIRP - Calculate and convert ERP and EIRP RMS voltage - Calculate the RMS voltage Pi attenuator - Calculate the values of the resistors by entering the attenuation and impedance T attenuator - Calculate the values of the resistors by entering the attenuation and impedance Inductors in series - Calculate the inductance of inductors in series Inductors in parallel - Calculate the inductance of inductors in parallel Doppler shift - Calculate the Doppler shift