Advanced Amateur Radio (Canada) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Radiocommunication Act authority

The Canadian statute under which amateur radio is regulated; ISED administers it and issues Amateur Radio Operator Certificates that serve as the station licence.

Advanced certificate privileges

Allows building and modifying transmitting equipment, up to 1000 W PEP output, and access to all amateur bands and modes not otherwise restricted.

Basic certificate power limit

Holders of the Basic certificate may operate commercially manufactured equipment at a maximum transmitter output of 250 W PEP.

Identification interval

A station must identify with its call sign at the start and end of each contact and at least every 30 minutes during the communication.

VE and VA prefixes

VE and VA call signs are assigned to stations in eastern Canada; VO denotes Newfoundland and Labrador, and VY denotes the northern territories.

Third-party traffic rule

Messages on behalf of another person are permitted only for personal matters and where the third party is Canadian or covered by an agreement.

National simplex calling frequency

146.520 MHz is the recognized national VHF simplex calling frequency; it should be kept clear for calling and emergency use.

Harmful interference response

Reduce power, change frequency, or cease transmitting; deliberate interference is prohibited and may be reported to ISED for investigation.

Ohm's law and power

E = I × R, and power P = E × I = I²R = E²/R; these relationships apply to DC circuits and to resistive AC loads.

Capacitive reactance formula

X_C = 1/(2πfC); reactance falls as frequency or capacitance increases, and a capacitor blocks DC while passing AC.

Inductive reactance formula

X_L = 2πfL; reactance rises with frequency and inductance, and an inductor opposes changes in current.

LC resonance formula

f = 1/(2π√(LC)); at resonance the reactances cancel, giving minimum impedance in series and maximum impedance in parallel circuits.

Decibel conversions

+3 dB doubles power, +6 dB doubles voltage, +10 dB is ten times power; dB = 10 log(P₂/P₁) or 20 log(V₂/V₁).

Wavelength formula

λ in metres equals 300 divided by frequency in MHz; a half-wave dipole is about 143/f(MHz) metres long.

Single sideband advantage

SSB transmits one sideband without a carrier, halving bandwidth and concentrating transmitter power in the information-bearing signal.

Receiver selectivity

The ability to reject signals on adjacent frequencies; it is determined mainly by the IF filter and is distinct from sensitivity.

F2 layer propagation

The highest ionospheric layer supports long-distance HF skywave; the maximum usable frequency depends on ionization and path geometry.

Coaxial cable impedance

Common coaxial feedlines have a characteristic impedance of 50 Ω (or 75 Ω), while parallel open-wire line is typically 300–600 Ω.

SWR formula

SWR = (1+|Γ|)/(1−|Γ|); 1:1 is a perfect match, 2:1 reflects about 11% of power, and 3:1 reflects about 25%.

Half-wave dipole impedance

A half-wave dipole has a feedpoint impedance near 73 Ω in free space, with a figure-eight pattern perpendicular to the wire.

Quarter-wave vertical

A quarter-wave vertical over a ground plane has about 36 Ω feedpoint impedance and radiates at low angles, favoring long-distance contacts.

Yagi director effect

Adding directors increases forward gain and narrows beamwidth; a typical three-element Yagi provides roughly 7–8 dBi gain.

Balun purpose

A balun converts between balanced and unbalanced feedlines and may also transform impedance, such as 4:1 for a folded dipole.

Velocity factor

The ratio of signal speed in a cable to the speed of light; coaxial cable typically has a velocity factor of 0.66 to 0.85.

Zener diode function

Operated in reverse breakdown, a Zener diode holds a nearly constant voltage and is used for voltage regulation and reference.

Transistor current gain

In a bipolar transistor, collector current equals beta times base current; beta is the forward current gain in the active region.

Full-wave bridge rectifier

Four diodes convert both AC half-cycles to pulsating DC; a filter capacitor then smooths the ripple before regulation.

Class AB amplifier

Conducts for more than half but less than the full cycle, giving better efficiency than Class A with acceptable linearity for SSB.

Class C amplifier

Conducts for less than half a cycle and is highly efficient but nonlinear, so it suits FM and CW rather than amplitude-modulated modes.

Crystal oscillator stability

A quartz crystal has very high Q, giving stable frequency; Colpitts, Hartley, and Pierce circuits are common oscillator configurations.

RFI suppression techniques

Ferrite chokes, bypass capacitors, shielded cable, and proper station grounding reduce interference from computers, power supplies, and lighting.

High-voltage safety

Amplifiers and power supplies store lethal voltages; discharge filter capacitors and disconnect power before servicing any equipment.