## Amateur Extra: Reactive Power in an Ideal Circuit

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors? [E5D09] A. It is dissipated as heat in the circuit B. It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated C. It is dissipated as kinetic energy in the circuit D. It … Read more

## General: Voltmeter Impedance

Why is high input impedance desirable for a voltmeter? [G4B05] A. It improves the frequency response B. It decreases battery consumption in the meter C. It improves the resolution of the readings D. It decreases the loading on circuits being measured Remember that impedance is the property of a circuit that prevents current from moving … Read more

## Technician: Correct Copy of Voice Traffic

What should be done to insure that voice message traffic containing proper names and unusual words are copied correctly by the receiving station? [T2C03] A. The entire message should be repeated at least four times B. Such messages must be limited to no more than 10 words C. Such words and terms should be spelled … Read more

## Amateur Extra: Op Amp Output Impedance

What is the typical output impedance of an integrated circuit op-amp? [E7G15] A. Very low B. Very high C. 100 ohms D. 1000 ohms A A. Very low output impedance is a property of an IC op-amp.   In an ideal case, it would be zero.  But of course that’s never possible. In reality, the behavior … Read more

## General: Frequency Deviation

What is the frequency deviation for a 12.21 MHz reactance modulated oscillator in a 5 kHz deviation, 146.52MHz FM phone transmitter? [G8B07] A. 101.75 Hz B. 416.7 Hz C. 5 kHz D. 60 kHz Whoa, what?  Guess what, dust off that calculator, because here’s where it starts to get mathy.  This question is also terribly … Read more

## Technician: Parallel Dipole

Which of the following describes a simple dipole mounted so the conductor is parallel to the Earth’s surface? [T9A03] A. A ground wave antenna B. A horizontally polarized antenna C. A rhombic antenna D. A vertically polarized antenna Lets recall what we mean when we talk about an electromagnetic field being “polarized.”  The direction of … Read more

## Amateur Extra: Sine Wave Odd Harmonics

What type of wave is made up of a sine wave plus all of its odd harmonics? [E8A01] A. A square wave B. A sine wave C. A cosine wave D. A tangent wave Well, the answer to this question is mathematically somewhat complex.  The answer is A. A square wave. Rather than try and … Read more

## General: Code in a PSK31 Signal

Which type of code is used for sending characters in a PSK31 signal? [G8C12] A. Varicode B. Viterbi C. Volumetric D. Binary Alright, here we are again at a real head scratcher.  This is yet another example of something you just “need to know” for the test.  In real life you really wouldn’t use this … Read more

## Technician: Mega vs. Giga

If a frequency readout shows a reading of 2425 MHz, what frequency is that in GHz? [T5B13] A. 0.002425 GHZ B. 24.25 GHz C. 2.425 GHz D. 2425 GHz The best way to figure this out is to review our metric prefixes.  If you’re into computers at all, you already use “Mega” and “Giga” and … Read more

## Amateur Extra: Satellite Mode Designators

What do the letters in a satellite’s mode designator specify? [E2A05] A. Power limits for uplink and downlink transmissions B. The location of the ground control station C. The polarization of uplink and downlink signals D. The uplink and downlink frequency ranges Lets look at “mode designators” to understand what the question is about.  A … Read more