📡 Stuff Every General Class Ham Should Know: Training Guide

Shared HF bands

General licensees may use every HF band, but on 80, 40, 20, and 15 meters some portions are reserved for higher license classes. Where Generals share only part of a voice segment, they get the upper frequency portion.

The 30 meter band is different. Voice and image operation is prohibited there for every license class. Only CW, RTTY, and data modes are allowed.

On 30 meters, US amateurs are a secondary service. They must not interfere with primary fixed stations from other nations, and they must accept interference from those primary stations.

10 meter repeaters

Repeaters on 10 meters are kept above 29.5 MHz. The rules bar repeaters from 28.0 to 29.5 MHz, so the 29.5 to 29.7 MHz slice is where they operate.

ITU regions and beacons

The International Telecommunication Union divides the world into three regions. North and South America are in Region 2, so US hams may use 40 meters up to 7.300 MHz, while Regions 1 and 3 stop at 7.200 MHz.

Amateurs should avoid transmitting on 14.100, 18.110, 21.150, 24.930, and 28.200 MHz because a worldwide network of propagation beacons operates there. FCC rules also let beacons run automatically in the 28.20 to 28.30 MHz segment.

Emergency drills

RACES stations may hold routine drills and tests up to one hour per week. Longer drills of up to 72 hours may occur no more than twice per calendar year with state emergency planning approval.

How power is measured

The FCC limits peak envelope power, or PEP, at the transmitter output. PEP is the average power over one RF cycle at the crest of the modulation envelope, not at the antenna.

A 30 meter station is capped at 200 watts PEP for every license class, much lower than the usual 1,500 watt amateur limit on most HF bands.

A beacon station may run no more than 100 watts PEP output, and it may transmit on only one channel per band from the same station location.

Special 60 meter rules

On 60 meters, every emission must fit within 2.8 kHz. Current rules allow operation in the 5351.5 to 5366.5 kHz segment plus four single channels.

Antenna structures and local rules

Away from airports, an antenna structure over 200 feet, or 60.96 meters, above ground must be reported to the FAA and FCC before construction. Near or at a public-use airport, additional rules apply.

State and local governments may regulate antenna structures, but under the PRB-1 rule they must reasonably accommodate amateur communications and keep rules to the minimum practical.

Licensing and exam credit

A Certificate of Successful Completion of Examination, or CSCE, proves an exam element was passed. It is valid for 365 days for credit toward the next exam.

A Technician waiting for a General upgrade to appear in the FCC database must add AG after the call sign whenever operating on General class frequency privileges. On Technician frequencies no extra tag is needed.

Volunteer Examiners, or VEs, must be at least 18 years old, accredited by a Volunteer Examiner Coordinator, and hold the right license class. Every exam session needs a team of at least 3 VEs.

Phone operating and sidebands

By convention, hams use upper sideband for voice on 14 MHz and higher, and also on VHF and UHF. Lower sideband is usual on 160, 75, and 40 meters.

No amateur station has priority access to a frequency outside emergencies. No frequency is assigned for the exclusive use of any station.

To break into a phone contact, say your call sign once between transmissions. If a station in distress breaks in, acknowledge it first and find out what help is needed.

Before you call CQ

A clear frequency may still have a weak station you cannot hear. Ask if the frequency is in use, then give your call sign. On CW, send QRL? which means "Are you busy?" or "Is this frequency in use?"

CW stations should keep 150 to 500 Hz between signals to avoid interfering. SSB needs 2 to 3 kHz spacing.

CW operating and prosigns

When answering a CQ in Morse code, use the fastest speed you can copy, but no faster than the CQ. If a CW station sends "QRS?", the polite reply is to send slower.

Zero beat means matching your transmit frequency to the received signal. Full break-in CW, called QSK, lets the sending station hear between the dots and dashes it sends.

AR is the prosign for end of a formal message in CW. SK ends a contact, BK is a break, and KN at the end of a transmission means you are listening only for a specific station or stations.

Low power and long path

QRP means low-power transmit operation. FCC rules also say every station must use the minimum transmitter power needed to carry out the contact.

For a long-path contact, aim your beam 180 degrees from the short-path heading. Skywave signals arriving by both short and long path can cause a slightly delayed echo.

The Sun drives propagation

Solar flare radiation arrives in about 8 minutes and can quickly disrupt daytime HF. A coronal mass ejection is much slower, taking 15 hours to several days to affect propagation.

A higher sunspot number means more active ionization, so higher HF bands such as 15, 12, and 10 meters are more reliable. The 20 meter band can usually support worldwide daytime propagation at any point in the solar cycle.

HF conditions can repeat on a 26 to 28 day cycle because the Sun's surface layers rotate around its axis.

Solar and geomagnetic indices

The solar flux index measures solar radiation at 10.7 centimeters. Hams use it as a quick gauge of how well higher HF bands work. During low solar activity, 15, 12, and 10 meters are the least reliable.

The K-index measures short-term stability of Earth's geomagnetic field. A low K-index means calm conditions, good for HF. The A-index measures long-term stability.

MUF is the Maximum Usable Frequency for a path between two points. LUF is the Lowest Usable Frequency for that path.

Ionospheric layers and skip

The D region is the lowest ionospheric layer and is the most absorbent for signals below 10 MHz in daylight. It makes 160, 80, 60, and 40 meters harder for long-distance work during the day, and at night the D region fades away.

One hop via the E region normally travels about 1,200 miles. Scatter propagation can let signals be heard inside the transmitting station's skip zone.

One hop via the F2 region normally travels about 2,500 miles, the longest because the F2 region is the highest.

Special propagation modes

NVIS, or near vertical incidence skywave, sends signals nearly straight up so they come back down close by. It is useful for short distance regional contacts. The highest frequency refracted back at a given angle is called the critical frequency.

Understanding meters and decibels

Voltmeters have high input impedance to decrease loading on the circuit being measured. An oscilloscope contains horizontal and vertical channel amplifiers.

An S meter reads received signal strength. Every 10 dB is a factor of 10 in power, so 20 dB over S9 is 100 times the power of S9.

One S unit is 6 dB. That means moving a receiver from S8 to S9 needs about four times the transmitter power.

A 3 dB increase doubles power, and a 3 dB loss cuts it in half. A 1 dB loss leaves about 79.4 percent of the power, so 20.6 percent is lost.

Impedance is the ratio of voltage to current. Its inverse is admittance. Reactance is the opposition to AC from a capacitor or inductor, measured in ohms and written as X.

AC, RMS, and power math

RMS voltage heats a resistor the same as a DC voltage of equal value. An incandescent bulb glows equally bright on 120 volts DC or 120 volts RMS AC.

For a sine wave, peak is RMS times 1.414. A 120 volt RMS sine wave has a peak-to-peak value of 339.4 volts. Going the other way, a sine wave of 17 volts peak has an RMS value of about 12 volts.

Power equals voltage squared divided by resistance. An 800 ohm load supplied with 400 volts DC consumes 200 watts. At 40 volts the same load uses only 2 watts.

For a 200 volt peak-to-peak signal across a 50 ohm dummy load, the peak is 100 volts, so PEP is 100 watts. For an unmodulated carrier, PEP equals average power.

Resistors, capacitors, transformers, and semiconductors

Three resistors in parallel: 10, 20, and 50 ohms total 5.9 ohms, always lower than the smallest branch. In series they total 80 ohms.

Capacitors in series combine like resistors in parallel. Three 100 microfarad capacitors in series give 33.3 microfarads. In parallel, capacitance adds, so those three would make 300 microfarads.

A transformer's voltage follows its turns ratio. A 500 turn primary and 1500 turn secondary turns 120 VAC into 360 volts. In a step-up transformer the primary winding wire is usually larger.

A silicon diode starts conducting at about 0.7 volts forward bias. A germanium diode starts lower, near 0.3 volts. An LED emits light when forward biased.

A wire-wound resistor is a coil of wire, so it adds unwanted inductance at RF. An inductor operated above its self-resonant frequency becomes capacitive.

A bipolar transistor used as a switch operates in saturation and cutoff. Saturation is fully on, and cutoff is fully off.

Practical circuits, filters, and power supplies

In a series LC circuit, equal inductive and capacitive reactance causes resonance and very low impedance. Inductor reactance increases with frequency; capacitor reactance decreases with frequency.

A notch filter cuts a narrow slice of the receive passband to reduce interference from carriers, and using the opposite sideband when receiving CW can also help. ALC prevents excessive drive to an RF power amplifier, but for AFSK data signals the ALC system should be inactive because ALC action distorts the signal.

To reduce RF interference to audio circuits, a bypass capacitor gives unwanted RF a path to ground. A ferrite choke on an audio cable adds impedance to common-mode RF current, and bonding equipment enclosures together helps minimize ground loops.

A power supply bleeder resistor drains filter capacitors after power is removed, making the supply safer to work on. A full-wave rectifier uses two diodes and a center-tapped transformer; unfiltered full-wave rectified DC pulses at twice the AC input frequency.

A switchmode power supply operates at high frequency, which allows smaller components. Among Class A, B, AB, and C, Class C has the highest efficiency, while Class A conducts 100 percent of the time.

A 3-bit binary counter has 8 states because 2 times 2 times 2 equals 8. A low-pass filter's cutoff frequency is where output power falls below half the input power, and a band-pass filter's bandwidth is measured between its upper and lower half-power frequencies.

Feed lines and connectors

Window line has a nominal characteristic impedance of 450 ohms, while most amateur coax is 50 ohms. The characteristic impedance of parallel conductor feed line depends on conductor spacing and radius.

Coax attenuation increases as frequency increases. Feed line loss is usually expressed in decibels per 100 feet, and higher loss reduces the SWR measured at the input to the line.

A 50-ohm feed line connected to a 200-ohm resistive load gives an SWR of 4:1. A 50-ohm feed line connected to a 10-ohm resistive load gives an SWR of 5:1.

A 50-ohm BNC connector keeps low SWR up to about 4 GHz. A type N connector is moisture resistant and useful to 10 GHz. An SMA is a small threaded connector suitable for signals up to several GHz.

A ferrite bead on a coax shield creates impedance in the path of common-mode RF current, reducing that current. How a ferrite core performs depends on the mix of materials used.

Antennas

A quarter-wave ground-plane vertical radiates equally in all compass directions, called omnidirectional in azimuth. The radial wires go on the surface or are buried a few inches below the ground.

A half-wave dipole for 14.250 MHz is about 33 feet long. The length in feet is roughly 468 divided by the frequency in MHz, so at 3.550 MHz it is about 132 feet.

In a three-element Yagi, the reflector is longer than the driven element and the director is shorter. The driven element is about a half wavelength. Increasing boom length and adding directors increases a Yagi's gain.

Gain in dBi is 2.15 dB higher than gain in dBd because a dipole already has 2.15 dBi of gain. Two three-element Yagis stacked half a wavelength apart give about 3 dB more gain than one.

A Beverage antenna is a long-wire antenna used for directional receiving on MF and low HF bands. It is a listening antenna, not a transmitting one. An electrically small loop has nulls broadside to the loop.

A corona ball on an HF mobile antenna reduces RF voltage discharge from the tip of the antenna. A capacitance hat electrically lengthens a physically short mobile antenna.

Digital modes and signals

RTTY sends two tones called mark and space. On amateur HF the usual shift is 170 Hz. If an RTTY signal will not decode, the mark and space tones may be reversed, the baud rate wrong, or the sideband wrong. In FSK the two frequencies are also called mark and space, and Baudot code is a 5-bit code with start and stop bits.

FT8 requires computer time accurate within about 1 second because stations use fixed time slots. When answering an FT8 CQ, choose a clear frequency in the alternate time slot. FT8 uses 8-tone frequency shift keying, and an FT8 report of +3 means a signal-to-noise ratio of +3 dB in a 2.5 kHz bandwidth. Common FT8 activity on 20 meters is near 14.074 to 14.077 MHz.

WSPR is a digital mode used as a low-power beacon to assess HF propagation. On a waterfall display, frequency runs horizontally, signal strength is the intensity, and time runs vertically.

PSK31 sends characters with Varicode. Upper case letters use longer Varicode sequences, so they slow the transmission. QPSK31 encoding provides error correction, and its bandwidth is about the same as BPSK31.

In software-defined radio, I and Q signals are offset by 90 degrees. Filtering, detection, and modulation can all be done in software. A mixer output contains the sum and difference of its local oscillator and RF input frequencies.

Single sideband has the narrowest bandwidth of common phone emissions. Overmodulation causes excessive bandwidth, and flat-topping is signal distortion from excessive drive or speech levels. FM phone bandwidth is about twice the sum of deviation and modulating frequency, so 5 kHz deviation plus 3 kHz modulation gives 16 kHz.

RF exposure and electrical safety

RF energy can heat body tissue. FCC exposure rules apply to all amateur stations with time-averaged transmission above one milliwatt, and those rules took effect May 3, 2021.

If station RF energy exceeds permissible human exposure limits, you must take action to prevent human exposure to the excessive RF fields. A station that fails the FCC exposure exemption criteria must be evaluated following FCC OET Bulletin 65.

AWG 14 wire is protected by a circuit breaker of at most 15 amperes. A 20-ampere breaker needs wire no smaller than AWG 12, according to the National Electrical Code.

A GFCI disconnects AC power when it detects current from a hot wire directly to ground. Only the hot wires in a four-conductor 240 VAC circuit should be attached to fuses or circuit breakers.

Before climbing a tower that supports electrically powered devices, lock out and tag every circuit that powers the tower. Proper lockout and tagout practices safeguard workers from hazardous energy releases. Also confirm that the climbing harness is rated for the climber's weight and is within its allowable service life.

A power supply interlock ensures dangerous voltages are removed if the cabinet opens. Lightning arrestors should be located where the feed lines enter the building.

Soldered joints should not be used in lightning protection ground connections because lightning heat can destroy solder. Use proper clamped or bolted connections. All metal station equipment enclosures must be grounded.