Frequencies

• Measured in Hz, number of cycles per second
• Audio: 20Hz-20kHz
• AM Radio: 640-1800 kHz
• FM Radio: 99-110MHz
• Common to work within MHz for calculations
• Speed of light: 300 million m/s
• Doubling a frequency = harmonics (like a musical note, high C, low C, going up/down an octave)
• Higher frequencies take more power
• Amplitude = power within frequency
• $c=f\lambda$
• 50 MHz = 6m wavelength
• For calculations with frequencies below 30MHz, use 286 million m/s for speed of light

Bandwidth Requirements

• CW/Morse: 100-500Hz
• RTTY: 600Hz
• SSB: 2.7 kHz for voice
• AM: 6 kHz for voice
• FM narrow band: only requires 3kHz, but generally requires you to leave 5kHz on each side, so roughly 15kHz of space is needed
• Bandwidth usually limited to 6kHz for under 30MHz
  • Exception: 20kHz for 28-29.7 MHz
  • Exception: 1 kHz for 10.1-10.15 MHz
  • Radio controlled models (i.e. drones, IC devices, etc) not allowed below 30kHz