Ham Radio General flashcards

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

General class 80m phone sub-band

General class operators may use phone on 80 meters from 3.800 MHz to 4.000 MHz.

Station identification requirement

FCC rules require transmitting your call sign at the beginning and end of each communication and at least every 10 minutes during a contact.

Maximum power for General

The maximum transmitter power output for General class is 1,500 watts PEP, except on 30 meters where it is 200 watts.

Third-party traffic

Messages relayed on behalf of a non-licensed person; allowed only with countries having a third-party agreement with the U.S.

RST system

Readability (1-5), Strength (1-9), Tone (1-9); Tone is used only for CW, not for phone.

Calling CQ

To initiate a general call, transmit "CQ" followed by your call sign; respond to a CQ by giving your call sign only.

Distress call

Use "MAYDAY" spoken three times, followed by your call sign and location, to indicate immediate danger to life.

Split operation

Transmitting on one frequency and receiving on another; listen on the DX station's transmit frequency and call on the announced frequency.

Sporadic E propagation

Dense patches of ionization in the E layer reflect VHF signals, enabling contacts over 1,000 miles.

Maximum Usable Frequency

The highest frequency that will be reflected by the ionosphere between two points at a given time.

Tropospheric ducting

Temperature inversions cause VHF/UHF signals to bend and travel beyond the horizon, sometimes hundreds of miles.

Skip zone

The area between the end of ground wave coverage and the first returning skywave signal; can be filled by NVIS on lower bands.

Dummy load

A 50-ohm non-radiating load used for testing transmitters to avoid interference.

SWR meter

Measures the ratio of forward to reflected power; an SWR of 1:1 is ideal, and above 2:1 may indicate a problem.

AGC settings

Automatic Gain Control: set to fast for CW and SSB, slow for AM, to prevent receiver overload on strong signals.

RIT

Receiver Incremental Tuning allows fine-tuning of a received signal without changing your transmit frequency.

Ohm's Law

E = I × R; I = E / R; R = E / I, where E is voltage, I is current, and R is resistance.

Power formulas

P = E × I; P = I² × R; P = E² / R, where P is power in watts.

Capacitive reactance

Xc = 1 / (2πfC), where f is frequency in Hz and C is capacitance in farads.

Resonant frequency

f = 1 / (2π√(LC)), the frequency at which inductive and capacitive reactances are equal.

Resistor color code

Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Gray=8, White=9; Gold=±5%, Silver=±10%.

Diode forward voltage

A silicon diode has a forward voltage drop of about 0.7 volts when conducting.

Transformer turns ratio

The voltage ratio equals the turns ratio; the impedance ratio equals the square of the turns ratio.

Capacitor types

Ceramic capacitors are stable and low capacitance; electrolytic capacitors are polarized and high capacitance; tantalum are stable and compact.

Full-wave bridge rectifier

Uses four diodes to produce pulsating DC at twice the input frequency and requires no center-tapped transformer.

Class C amplifier

Highly efficient but distorts the signal; used for FM and CW, not for SSB.

Voltage regulator

An IC such as 7805 or 7812 maintains a constant output voltage; input must be at least 2V above output.

Mixer

Combines two signals to produce sum and difference frequencies; used in receivers for frequency conversion.

Carson's rule

FM bandwidth ≈ 2 × (peak deviation + modulating frequency).

SSB bandwidth

Single sideband (J3E) transmits one sideband and suppresses the carrier, reducing bandwidth to about 3 kHz.

Dipole length formula

Half-wave dipole length in feet = 468 / frequency in MHz; quarter-wave vertical = 234 / frequency in MHz.

RF exposure evaluation

FCC requires stations to be evaluated for RF exposure compliance based on frequency and power density.