TinySA

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TinySA - Spectrum Analyzer

  • Maximum input level
    • 0 dBm = 1 mW
    • dBm = 10*LOG(milliwatts)
    • -10 dBm = 0.1 mW
    • +10dBm = 10 mW
    • +20dBm = 1000 mW
  • 3.3V at 50 Ohm = 0.2178W
    • 217.8 mW = 23.4 dBm
  • tinySA wiki

Attenuators

30 dB Attenuator

30dB Attenuator.PNG

  • Built
    • Standard 5% resistor values
    • R2 = 2 paralleled 120 Ohm 1/4W resistors paralleled with 470 ohms = 53.2 ohms
    • R1 = 820 in parallel with 22K = 790.6 ohms
    • Flat from 0-30 MHz
    • Measured attenuation is flat
      • -30.01dB at 1 MHz
      • -30.24dB at 30 MHz
    • 53.1 ohms, 21.3nF
    • SWR 1.06
    • 1/2W max (5VDC max, 0 ohm source)
  • LTSPICE Simulation

LTSPice 30dB.PNG

20 dB Attenuator

20dB Attenuator.PNG

  • Build
    • Standard 5% resistor values
    • R2 = 2 paralleled 150 Ohm 1/4W resistors paralleled with 330 ohms = 61.11 ohms
    • R1 = 510 in parallel with 8.2K = 247.3 ohms
    • Flat from 0-30 MHz
    • Measured attenuation is flat
      • -tbd dB at 1 MHz
      • -tbd4dB at 30 MHz
    • tbd ohms, tbd nF
    • SWR tbd
    • 1/2W max (5V max, 0 ohm source)
  • LTSPICE Simulation

Videos