The relationship between voltage (V), current (I) and resistance (R) in a simple DC circuit is given by Ohm's law. Which expression correctly states it?
Basic Electrical Radio Theory
Question · Easy
A 12 V supply is connected across a 6 ohm resistor. How much current flows through the resistor?
A transmitter delivers 0.5 A at 20 V to its final stage. What is the DC input power?
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What is the SI unit of electrical resistance?
A frequency of 7 100 kHz is the same as which value expressed in megahertz?
The wavelength of a radio signal is related to its frequency by the speed of light (about 300 000 000 m/s). Approximately what wavelength corresponds to a frequency of 150 MHz?
Question · Medium
Using the shortcut wavelength (m) = 300 / frequency (MHz), what is the approximate wavelength of a 7.1 MHz signal?
Two resistors of 100 ohm each are connected in series. What is the total resistance?
Which component stores energy in an electric field and blocks DC while passing AC?
What does a diode do in an electronic circuit?
An alternating current (AC) waveform differs from a direct current (DC) waveform because AC:
The frequency of an AC waveform is measured in:
If the frequency of a radio signal increases, its wavelength:
A transmitter draws 13.8 V at 3 A. What DC input power does this represent?
What is the main purpose of a fuse in a transceiver's DC power lead?
In the abbreviation 'SSB', the letters stand for:
Transmitters Receivers
Single sideband (SSB) is best described as a form of:
In frequency modulation (FM), the information is carried by varying the carrier's:
On a simple transmitter block diagram, what is the role of the oscillator stage?
What is the function of the power amplifier stage in a transmitter?
In a superheterodyne receiver, what is the purpose of the mixer stage?
Question · Hard
When setting up a station for SSB voice operation on HF, which microphone gain setting is generally best?
What does a transceiver's S-meter indicate?
A Foundation licensee in Australia operating under the amateur class licence must:
A half-wave dipole cut for 7.1 MHz has an overall length of approximately:
Antennas Feeders
A standing wave ratio (SWR) of 1:1 on a feedline indicates that:
A high SWR on a coaxial feedline is undesirable mainly because it can:
What is the main purpose of an antenna matching unit (also called an ATU or AMU)?
Coaxial cable is widely used as an amateur feedline because it:
A quarter-wave vertical antenna typically requires which of the following to work effectively?
A half-wave dipole radiates most strongly:
Why should the braid (shield) of coaxial cable be correctly connected at the connector?
The HF amateur bands are most useful for long-distance (DX) contacts mainly because signals can be:
Propagation
Compared with HF, signals on the 2 m (VHF) band usually:
Ionospheric propagation on HF tends to change between day and night because:
During daytime, which of these amateur bands is generally most useful for long-distance contacts?
What is meant by 'ground wave' propagation?
Your transmission causes interference to a neighbour's audio system. The neighbour's equipment is most likely affected because it:
Interference Emc
A practical first step to reduce RF breakthrough into a neighbour's hi-fi system is often to:
Which transmitted mode is generally most likely to cause noticeable interference problems if over-driven?
Harmonics produced by a transmitter are:
If your transmission interferes with a neighbour and you cannot quickly resolve it, the best initial approach is to:
In the standard phonetic alphabet used in amateur radio, the letter 'Q' is spoken as:
Operating Procedures
Using the standard phonetic alphabet, how would you correctly send the letters 'V K'?
Australian amateur radio callsigns begin with which prefix?
In an Australian callsign such as VK5XYZ, what does the number after 'VK' generally indicate?
The Q-code 'QRM' is generally used to mean:
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