Ham Radio Extra flashcards
Ham Radio Extra · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- License term length
- An amateur operator/primary station license is granted for a term of 10 years and may be renewed for additional 10-year terms.
- Grace period for renewal
- After license expiration, the FCC allows a 2-year grace period during which the license may be renewed without retaking the examination.
- Control operator responsibility
- The control operator is responsible for the proper operation of the station, regardless of whether control is local, remote, or automatic.
- Third-party communication rule
- On phone, third-party messages may be transmitted when the amateur receives no payment and the control operator is present for non-amateur-originated messages.
- Prohibited international message content
- International amateur communications are limited to technical information or personal remarks; messages encoded to obscure meaning are prohibited except for control and telemetry.
- Automatic control authorization
- Automatic control is permitted for beacons, repeaters, auxiliary stations, and space stations on specified bands; it is not allowed for routine HF phone contacts.
- RST signal report
- RST reports Readability (1-5), Strength (1-9), and Tone (1-9 for CW). SSB reports omit the tone figure and use only R and S.
- Message precedence levels
- Formal traffic uses four precedence levels: Emergency for life or property, Priority for urgent, Routine for ordinary, and Welfare for disaster inquiries.
- Split frequency operation
- Split operation transmits on one frequency and listens on another; the listening frequency is announced so callers know where to reply.
- Station identification interval
- The station must identify with its call sign at least every 10 minutes during a communication and at the end of each communication.
- Repeater offset standards
- VHF and UHF repeaters commonly use a 600 kHz offset on 2 meters and a 5 MHz offset on 70 centimeters, with CTCSS tones for access.
- Break-break meaning
- The term break or break-break is reserved for emergency or priority traffic; routine interruptions should wait for a natural pause in the conversation.
- Net control station role
- A net control station manages check-ins, directs the order of transmissions, and maintains orderly handling of messages on the net frequency.
- Ohm's law and power
- Ohm's law states V = I × R; power equals V × I, or I²R, or V²/R, linking voltage, current, resistance, and power.
- Capacitive reactance formula
- Capacitive reactance is Xc = 1/(2πfC); it decreases as frequency or capacitance increases, opposing current flow with a −90° phase shift.
- Inductive reactance formula
- Inductive reactance is Xl = 2πfL; it increases with frequency and inductance and shifts current −90° relative to voltage.
- Resonant frequency formula
- A resonant LC circuit has f = 1/(2π√(LC)); at resonance inductive and capacitive reactance cancel and the circuit presents only resistance.
- Decibel definitions
- For power, dB = 10 log(P2/P1); for voltage, dB = 20 log(V2/V1). A 3 dB change represents a factor of two in power.
- Class C amplifier conduction
- A Class C amplifier conducts for less than 180° of the input cycle, giving high efficiency but nonlinear operation suited to constant-envelope modes like FM.
- Class A amplifier conduction
- A Class A amplifier conducts for the full 360° of the input cycle, providing linear amplification at the cost of relatively low efficiency.
- Carson's rule
- Carson's rule estimates FM bandwidth as 2(β + 1) times the modulating frequency, where β is the modulation index (deviation divided by modulating frequency).
- Mixer output products
- A mixer combines two signals to produce sum and difference frequencies; the difference product is used in superheterodyne receivers and the sum in up-conversion.
- Skin effect
- At RF, current concentrates near the conductor surface, raising effective resistance as frequency increases and reducing the benefit of thick conductors.
- Cascaded noise figure
- In cascaded stages, overall noise figure is dominated by the first stage; high first-stage gain reduces the contribution of later stages.
- Half-wave dipole impedance
- A half-wave dipole in free space presents a feedpoint impedance near 73 ohms and a gain of about 2.15 dBi over an isotropic radiator.
- dBi versus dBd
- dBi references an isotropic radiator; dBd references a half-wave dipole. The conversion is dBd = dBi − 2.15.
- Coax impedance formula
- Coaxial cable characteristic impedance is approximately Z0 = (138/√εr) log(D/d), where D is shield inner diameter and d is center conductor diameter.
- VSWR to reflection coefficient
- VSWR = (1 + |Γ|)/(1 − |Γ|). A 2:1 VSWR corresponds to a reflection coefficient of 0.333 and about 11 percent reflected power.
- Quarter-wave line transformation
- A quarter-wave transmission line transforms impedance as Zin = Z0²/Zload, allowing a quarter-wave section to match dissimilar impedances.
- Half-wave line impedance repeat
- A half-wave transmission line repeats the load impedance at its input, regardless of the line's characteristic impedance.
- MPE averaging time
- Maximum permissible exposure limits are averaged over 6 minutes for controlled environments and 30 minutes for uncontrolled, general-population environments.
- RF exposure environment types
- Controlled (occupational) environments permit higher maximum permissible exposure than uncontrolled environments where the general public may be exposed.