HB3YAQLucerne
TOOLS · CALCULATE & EXPERIMENT
Your radio tools.
Calculate antenna dimensions and radio values, or try settings in the learning labs.
YOUR REFERENCE LIBRARY
22 / 22All tools
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Antennas & feed lines
Wavelength
Convert frequency to wavelength, half wave and quarter wave.
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Signals & measurement
SWR & reflection
Reflection coefficient, return loss and power fractions.
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Propagation & navigation
Free-space path loss
Ideal path loss from frequency and distance.
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Station practice
Battery runtime
Runtime from usable capacity and receive/transmit current.
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SDR & reception
Frequency error in ppm
Translate oscillator tolerance into actual frequency error.
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Antennas & feed lines
Half-wave dipole
Overall length and both arms of a centre-fed dipole.
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Antennas & feed lines
Quarter-wave radiator
Find starting dimensions for a radiator and radials.
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Antennas & feed lines
Electrical cable length
Quarter- and half-wave lines using the cable’s velocity factor.
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Signals & measurement
Power ratio in dB
Compare two powers and interpret their ratio.
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Signals & measurement
dBm, watts & volts
Convert absolute level to power and RMS voltage.
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Antennas & feed lines
Cable loss
Apply a data-sheet attenuation to your length and power.
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Propagation & navigation
Link budget
Follow transmit power, gains and losses to the receiver.
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Propagation & navigation
Radio horizon
Estimate the geometric horizon of two antennas with a k-factor.
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Propagation & navigation
First Fresnel zone
First Fresnel-zone radius at a point along a path.
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Station practice
DC voltage drop
Include both copper conductors and temperature.
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Station practice
Ohm’s law & power
Current and power dissipation in a resistor.
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Signals & measurement
LC resonance
Resonant frequency and characteristic impedance of an ideal LC circuit.
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Signals & measurement
Inductive & capacitive reactance
How an inductor and capacitor respond at a frequency.
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Antennas & feed lines
Quarter-wave impedance transformer
Line impedance and length between two resistive impedances.
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SDR & reception
Thermal noise
Noise power from temperature, bandwidth and noise figure.
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Signals & measurement
EIRP & ERP
Combine transmit power, feed-line loss and antenna gain.
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Propagation & navigation
Locator, distance & bearing
Compare Maidenhead grid centres on a map.
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Interactive learning
01 · SDR
The signal in your hands.
Experiment with tuning, filters and modes. Five exercises in an explicitly simulated waterfall.
Open SDR learning lab →02 · SIGNAL PATHFrom antenna to audio.
Change the antenna, cable, gain and filter in a simulation. Follow how the wanted signal and noise develop.
Explore the signal path →03 · FREQUENCIESUnderstand the band.
Explore Swiss amateur bands. Distinguish frequencies, band plan recommendations and licence categories.
Open frequency navigator →