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Radiocert

Radio & Electronics Foundations

The physics, math, and circuit vocabulary every radio credential assumes. Built so that a lesson in any exam track can point here instead of re-teaching Ohm's law for the fourth time.

Modules
5
Study time
130 min

Modules

  1. 01 Electrical Basics

    DraftT5A · T5B · T5C · T5D

    Charge, current, voltage, resistance, and power — the five quantities every later lesson assumes, plus the two circuit arrangements everything is built from.

    1. 01Charge, Current, and VoltageName the three quantities every circuit is described with, say which units they use, and explain why voltage is always measured between two points.
      7:27
      8 min
    2. 02Metric Prefixes and Unit ConversionConvert fluently between milli, micro, kilo, mega, and pico so that the dozen pool questions built entirely on prefix arithmetic become free marks.
      9:34
      9 min
    3. 03Ohm's LawSolve for voltage, current, or resistance given the other two, and recognise which of the three a word problem is actually asking for.
      5:14
      10 min
    4. 04Power, and Why Things Get HotCompute power from any two of voltage, current, and resistance, and use the I-squared form to predict where a station will overheat.
      5:20
      9 min
    5. 05Series and ParallelTell series from parallel by what is shared, combine resistances either way, and know why capacitors break the pattern.
      5:26
      10 min

  2. 02 AC, Frequency, and Wavelength

    DraftT3B · T5A

    What changes when current alternates: cycles, frequency, wavelength, and the three different voltages a single waveform can be said to have.

    1. 01Alternating CurrentSay what makes a current alternating, why radio requires it, and what a cycle and a hertz actually count.
      4:45
      7 min
    2. 02Frequency and WavelengthConvert between frequency and wavelength in your head, and explain why every amateur band has two names.
      6:34
      9 min
    3. 03Reading a Waveform: Peak, Peak-to-Peak, and RMSConvert between the three voltages a single AC waveform has, and know why a scope and a multimeter disagree about the same signal.
      5:34
      9 min

  3. 03 Reactance and Resonance

    DraftT5C

    Capacitors and inductors oppose AC in opposite, frequency-dependent ways. Where those oppositions cancel is where radio happens.

    1. 01Capacitance, Inductance, and ImpedanceName the two ways a circuit stores energy, give their units, and say what impedance is that resistance is not.
      6:03
      9 min
    2. 02Resonance, and Why Everything in Radio Is 50 OhmsExplain resonance as two reactances cancelling, tell series from parallel resonance, and say what impedance matching buys you.
      7:00
      11 min

  4. 04 Decibels and Measurement

    DraftT5B · T7C

    The logarithmic shorthand the whole hobby speaks in, and the instruments that report in it.

    1. 01Decibels Without the LogarithmsAnswer every decibel question in the amateur pools using three memorised anchors and addition, without touching a calculator.
      6:20
      10 min

  5. 05 Electrical and RF Safety

    DraftT0A · T0B · T0C

    What can actually hurt you in a radio station, in rough order of how likely it is to happen.

    1. 01Electrical Safety in the StationWire, fuse, and ground a station without creating the three hazards that actually injure amateurs: shock, fire, and stored charge.
      6:32
      10 min
    2. 02Antennas, Towers, and Power LinesPut up an antenna without contacting a power line, and know the tower rules that exist because someone died learning them.
      4:40
      8 min
    3. 03RF ExposureExplain why exposure limits vary with frequency, compute how duty cycle changes them, and say who is responsible and when a station must be re-evaluated.
      5:45
      11 min