Amateur Extra: What is a Parametric Amplifier?

Variable Capacitor

Today’s exam question comes from the Amateur Extra exam, Sub-element 7 (Practical Circuits) and Section B, (Amplifiers)…  [E7B20] What is a parametric amplifier? A. A type of bipolar operational amplifier with excellent linearity derived from use of very high voltage on the collector B. A low-noise VHF or UHF amplifier relying on varying reactance for …

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General: Units of Impedance

Complex Impedance

This week’s General Class question comes from sub-element 5 (Electrical Principles) group A (impedance) [G5A10] What unit is used to measure impedance? A. Volt B. Ohm C. Ampere D. Watt Impedance is the measure of opposition to current flow in a circuit when an AC voltage is applied.  With that in mind, we can automatically …

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Technician: Electromotive Force

Millivolt Meter

This week’s Tech question is from sub-element 5 (Electrical Principles) group A (units) [T5A11] What is the basic unit of electromotive force? A. The volt B. The watt C. The ampere D. The ohm This is one of the fundamental concepts when dealing with electricity, and therefore radio.  The standard units that we use to …

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Amateur Extra: Identifying in a Pileup

From the realm of “Good Operating Practice” we get our question of the week from the Amateur Extra exam. [E2C11] How should you generally identify your station when attempting to contact a DX station working a pileup or in a contest? A. Send your full call sign once or twice B. Send only the last …

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General: Increasing Inductance

This week’s General question comes from the section on circuit components. [G5C14] Which of the following components should be added to an inductor to increase the inductance? A. A capacitor in series B. A resistor in parallel C. An inductor in parallel D. An inductor in series The answer, is D. An inductor in series.  …

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General: Using Wind Power

Which of the following is a disadvantage of using wind as the primary source of power for an emergency station? [G4E11] A. The conversion efficiency from mechanical energy to electrical energy is less than 2 percent B. The voltage and current ratings of such systems are not compatible with amateur equipment C. A large energy …

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Amateur Extra: Non-linear Phase Response

Which of these modes is most affected by non-linear phase response in a receiver IF filter? [E7C14] A. Meteor Scatter B. Single-Sideband voice C. Digital D. Video The answer is C. Digital.  Why? Well, for one, the question is pretty vague.  If you’re using a Frequency Shift Keying (FSK) digital signal you probably won’t have …

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General: 2m RTTY/Data Symbol Rate

What is the maximum symbol rate permitted for RTTY or data emission transmissions on the 2 meter band? [G1C11] A. 56 kilobaud B. 19.6 kilobaud C. 1200 baud D. 300 baud The answer is B. 19.6 kilobaud.  But why?  It has to do with the amount of bandwidth used by a signal.  1200 and 300 …

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