Fundamental Basics
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Below are a few of the most fundamental concepts that all amateur radio operators should have seared into their brains. Familiarity with these concepts is required to earn the Technician Class license, and they will be used throughout your ham career.

Ohm's Law

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Power Calculation

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Ohm's & Power Calculation Combined

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Sine Wave
Relationship between Frequency and Wavelength

Frequency - Number of cycles completed in one second. Measured in Hertz.
(Above example = 2 Hz.)
Wavelength - Distance traveled in one cycle. Measured in meters.

Period - Amount of time required for one cycle. Measured in seconds.

Amplitude - Strength of the signal; height of the sine wave.
Usually measured in volts or amperes.

RMS = Root Mean Square =
the value of the constant direct current that would produce
the same power dissipation in a resistive load.

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Frequency - Wavelength Conversion

Where:
λ = Greek letter Lambda = Wavelength in meters
f = Frequency in megaHertz
300 = Approximate speed of light, in million meters per second

Note: This conversion is approximate. See the Frequency and Wavelength Conversions section of our Constants and Formulas page for more exact information.

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 Symbol Frequency Range Wavelength Range Description VLF 3 to 30 kHz 100 - 10 km Very Low Frequency LF 30 to 300 kHz 10 - 1 km Low Frequency MF 300 to 3,000 kHz 1,000 - 100 m Medium Frequency HF 3 to 30 MHz 100 - 10 m High Frequency VHF 30 to 300 MHz 10 - 1 m Very High Frequency UHF 300 to 3,000 MHz 1,000 - 100 mm Ultra High Frequency SHF 3 to 30 GHz 100 - 10 mm Super High Frequency EHF 30 to 300 GHz 10 - 1 mm Extremely High Frequency - - 300 to 3,000 GHz 1,000 - 100 µm Infrared

See our Electromagnetic Spectrum page for more details.

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Decibels

dB = 10 log10(P1/P2)

 Decibels Watts (+/-) 3 dB x 2 6 4 9 8 10 10 12 16 15 32 18 64 21 128

Example: Increasing the power by 9 dB is equal to multiplying the watts by 8.

See the Power Conversions section of our Constants and Formulas page, and our Decibels page for more information.

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Resistor Color Code