Amateur Radio technician pool topics

This is a list of topics we want to cover in an introductory amateur radio lecture / crash course.

The intent is to

• Grab interest in amateur radio for those who don't know what it is and keep it fun
• Cover topics in questions on the technician exam
• Surround this material with supporting material that will make the critical parts more memorable
• Leave new hams with the foundation of knowledge (beyond the exam) needed to become good technician operators
• give a taste of material on the general and extra exams where it is closely enough related to be easy to cover

See also: Amateur radio glossary

(stopped at T0A07)

Topics in the question pool

This is based on the 2022-2026 technician question pool. (Will add markers for future differences later.)

• Problematic questions: T2C09(dangerous) T3A08(ambiguous) T3A07(conflict) T4A11(obsolete?) T1D03(mismatch97) T8C09(2ans) T8D12(ambiguous)
• Null questions: T1A11 T1E01(?) T1E02(?) T1E06 T2C01 T3A12
• questions not covered: T4B02 T7B08 T7B09 T7B11

misc

• Purpose: Advancing skills in the technical and communication phases of the radio art (97.1)
• Govt. Agencies that regulate us: FCC (97.1), FAA
• Agencies that we cooperate with: FEMA, NWS(skywarn)
• services within amateur radio: (97.3(a)(38), 97.407)
  • ARES(ngo under ARRL), interfaces with local govt for emcomms
  • RACES (Legal entity): civil defence communications activated during national emergency
• willful interference (QRM vs QRN)
• talking to ISS (97.301, 97.207(c)

Identification

• Must ID (at least) every 10 minutes and on final transmission (Qx2)
  • exceptions: control model craft (97.119(a))
  • tactical calls (or call signs) can be used at the beginning of transmission
• Phone mode must use english language to ID
  • use of phonetic alphabet is encouraged (97.119(b)(2))
  • CW can also be used
• Call sign length based on license level 1 or 2 by 3 for tech
• call sign may have a selected suffix using ( / slant slash stroke) followed by a valid US letter (97.119(c)) and not conflict with other indicators or prefixes

Licensing

• Each operator may have exactly one primary station license (97.5(b)(1)])
• A trustee (like Steve) may also hold one club license (like our club's K4UCF) which is not a primary operating license if the club has at least 4 members
• The proof of license is its existence in the FCC ULS database (97.7), call sign is effective as soon as it shows up (97.5a)
• currently issued license classes: Technician, General, Extra
• vanity call system, including US Amateur Radio Call Signs
• FCC must be able to contact you by snail mail e-mail (97.23) (Qx2)
• renew every 10 years
• renew within 2 years after expiration or you'll lose the call sign
• (past question) renew no sooner than 90 days or it will be rejected

Station records

• (*)Station should log when the control operator is not the station licensee (97.103(a)}
• station records should include antenna gain when not a dipole, possibly as manufacturer specs
• (*)Records must be made available to FCC for inspection on demand (97.103(c))
• original information transmitted as spread spectrum must be kept in station records

Frequencies and band plans

• 10m SSB phone and data for technician, max PEP 200w
• 6m (band edges)
  • magic band and why its called that
  • 6m can propagate via modes common to both VHF and HF including sporatic E, skywave (during sun spots), aurora, ducting, meteor scatter, ground wave, and several of those are unpredictable
• 2m (band edges)
  • 219-220MHz: fixed digital forwarding only
• 50.0 - 50.1, 144.0-144.1 CW only
• primary and secondary allocations
• interaction of band edges, signal bandwidth, calibration, and drift
• VHF+ band use: CW, SSB, FM, mostly max 1500W PEP
• Calling frequencies: FM/146.520

Signals emissions and modes

• single side band (SSB) is a form of amplitude modulation (AM) but uses half the bandwidth
• packet radio on VHF commonly uses FM.
• PM (phase modulation) is strongly related to FM
• FM is typically used on VHF and UHF for local voice contacts especially on repeaters
• even on UHF/VHF, horizontally polarized SSB is better for weak signal long distance contacts
• ranked bandwidths (small to large) CW (150-400Hz), SSB voice (2.8-3kHz) = SSTV, AM voice (6khz), FM voice (7khz?-14khz), ATV/AM tv fast scan (6MHz)
• USB is used for 10m band
• AM signals combine and can be distinguished, FM signals interfere and cause buzzing (double) (strongest signal wins)

Repeater operation

• originating station is responsible
• 2m offset is commonly +/- 600 kHz
• 70cm offset is commonly +/- 5MHz
• call someone or respond to someone with TheirCall YourCall
• "reverse" function on radio swaps repeater transmit/receive freqs
• subaudible tone (CTCSS) or DCS code
• DTMF
• linked repeaters
• FM overmodulation distortion from clipping
• SSB overmodulation distortion from ALC
• DMR talk groups
• DMR color code for access
• IRLP, echolink uses DTMF to access other nodes using Voice over IP (internet linking)

Protocol and politeness

• listen / is this frequency in use / CQ CQ
• negotiate use of frequency if there is a conflict
• net control: Call the net to order and direct communications between stations checking in
• spell using the standard phonetic alphabet when clarity is needed
• "traffic" radiogram message
  • NTS system to accurately transmit messages by voice
  • preamble has metadata to track and prioritize the message
  • includes a "check" that counts word and symbol groups

Terms

(see glossary for full definitions)

• Part 97
• beacon (97.3(a)(9))
• broadcast/ one way transmission to the general public
• space station (>50km) (97.3(a)(41))
• Volunteer Frequency Coordinator (97.3(a)(22))
• Repeaters, auxiliary stations, remote stations
  • originating control operator is responsible
• control operator (required for all transmission, responsible for license class)
• control point
• third party (communications, traffic)
• repeater offset
• band plan: FCC established privileges + voluntary and customary uses
• Simplex / full duplex (definition, use)
• squelch
• traffic: formal messages accurately exchanged on a net
• key / electronic keyer : used for CW
• net control (above)
• dummy load
• Antenna analyzer
• SWR: 1:1=perfect; impedance mismatch  ; solid state power reduction; power loss especially in coax
• impedance: complex resistance in AC circuits; 50 ohms used in amateur radio; 75 ohms used for tv reception; antenna tuner matches impedance
• Directional watt meter (T7C08)
• volt meter
• Radio direction finding
  • directional antennas
• contesting
• grid locator
• gateway
• NTSC aka fast scan TV
• PSK: Phase shift keying
• DMR
• packet radio
• WSJT-X software; used for EME, weak signal, and meteor scatter
• ARQ automatic repeat request

Restrictions

These are prohibited:

• commercial use
• broadcasting
  • multiple exceptions to one way comms that are not considered broadcasting
  • can support broadcasting / news gathering directly related to life safety and property protection
• countries can notify the ITU they don't want hams communicating... (97.111(a)(1))
• encoding to obscure meaning is prohibited except telecommand to space stations or radio control craft (97.211(b), 97.215(b), 97.113(a)(4))
• music except ... (97.113(a)(4), 97.113(c))
• transmission for profit prohibited except...
  • trader's net
  • classroom instruction
• indecent or obscene language

Third party traffic

• licensed and responsible control operator required
• foreign stations only allowed when US has a third party agreement ([97.115(a)(2))

Boats and planes

• boat registered in the US and in international waters
• plane: must get permission from pilot (Pilot must follow FAA rules)

Satellites

• sat telemetry typically sends beacons that include health and status of the sat
• using excess power blocks other users from using the sat
• sat tracking programs show
  • maps showing sat position
  • time, azmuth, elevation of the start, max altitude, and end of pass
  • sat frequency including doppler shift
• Sats can use modes SSB FM CW or other data modes
• sat modes: UV -> uhf/vhf uplink/downlink
• spin fading from a tumbling sat with linear antennas being received with linear antennas
• LEO -> low earth orbit
• ideal power when the sat beacon is the same signal strength as your downlink repeat

Q codes and prosigns

prosigns / procedural signals

CQ

calling any station

TheirCall monitoring

listening and ready to talk

QRM / QRN

man made and natural noise

QSY

changing frequency

Propagation and wave properties

• (VHF) multipath propagation and fresnel zones / picket fencing (Qx2)
• (UHF) absorption by vegetation
• (VHF/UHF) horizontal polarization for long distance CW and SSB
• (VHF/UHF) penalty for (linear) cross polarization
• reflections off of buildings and obstructions
• precipitation attenuates microwave frequencies
• ground wave
  • refraction of UHF/VHF more than visual
• ionosphere / skywave propagation
  • HF(regularly) VHF(rarely) UHF(almost never) (Qx3)
  • faraday rotation makes HF elliptically polarized
  • different bands during different times of the day (Qx1) and sunspot cycle (Qx1)
    • 20-40 reflected/refracted during the day
    • 6m, 10m helped during high solar flux
  • Regions: F reflects, D absorbs
• Electric and magnetic fields are perpendicular in a EM wave (Qx2)
• Polarization refers to the electric field orientation
• speed of light in free space
• wavelength = c / frequency ; meters = 300 / MHz ; c=3e8 m/s (Qx3)
• bands identified by wavelength or frequency
• HF=3MHz-30Mhz ; VHF=30MHz-300MHz ; UHF=300kHz-3Ghz
• auroral backscatter
  • CME!
  • doppler shift and also irregular
  • vhf too!
• Sporatic E propagation
  • (probably enhanced by meteor showers; seasonal)
  • VHF (2m-10m) over the horizon
• Knife edge propagation
  • refraction over buildings and mountains
• Tropospheric ducting (Qx2)
  • weather inversion
  • uhf/vhf > 300mi is possible
• Meteor scatter
  • mostly 6m

Operational and technical

• power = volts * amps
• but also radios can be <50% efficient
• 13.8v is common
• SWR meters have a max power and valid frequency range
• I2R losses minimized by short thick wires; losses result in voltage drop
• digital operations audio hookup, PTT (control?) (Qx3)
• Digital modes include packet radio, IEEE 802.11, FT8, FT4, APRS
• Bonding ground with flat copper strap is preferred (why?)
• batteries: Ah (time)
• hot spot for internet + digital modes
• station setup: radio -> amp/tuner -> SWR meter -> feedline -> (tuner/LNA) -> antenna
• overmodulation issues
• front end overload issues, including consumer equipment
• splattering, spurious emissions, and harmonics
• effects of being off frequency (FM, SSB)
• common mode current and chokes (air balun, ferrite core; rf burns, distorted audio)
• filters for consumer equipment
• band pass and band reject filters for neighbors and rejecting broadcast
• transmission line / feed line
  • coax ; weather failure; UV resistance, easier to install (2022 T9B03), higher loss at higher frequencies or higher SWR
  • water intrusion increases loss in coax
  • parallel line: lower loss, more tolerance to high swr, sensitive to surrounding conductive objects including the ground
  • coax ranked by loss highest to lowest: RG-58, RG-213, RG-8, hardline
  • dielectric material in coax causes loss; replacing it with air reduces loss at the cost of increased chance of water intrusion; solid dielectric, foam dielectric, air core
• connect volt meter in parallel across a component to measure voltage; connect an ampmeter in series with the component to measure current
• applying voltage to an ohm meter or a multimeter in ohm mode can damage it; check for voltage first, make sure the circuit is not powered
• acid core solder should only be used for plumbing; residual acid causes instant corrosion when a current is applied
• a cold solder joint may appear rough and lumpy and is not well attached to both contacts
• an ohm meter connected to a discharged capacitor will show a short at first but resistance will appear to increase as the cap is charged by the meter
• gain

  amplifier gain

  ratio of input to output, represents power added

  antenna gain

  the increase in signal strength in a specified direction compared to a reference antenna (dBi=isotropic, dBd=dipole), usually measured in decibels; represents power concentrated; antenna gain, directivity, and radiation pattern are directly related

Antennas

• Beam antenna
• loaded antenna uses inductors to shorten antenna
• horizontal polarized antenna
• shortened HT whip antennas (compromise antenna)
• shortening a dipole increases resonant frequency
• antennas ranked by gain: isotropic, 1/4 wave monopole whip or 1/2 wave j-pole, 5/8 wave whip, yagi
• using a HT whip in a car has reduced effectiveness due to being shielded by the car body
• 1/4 wavelength at 146MHz is about 19" (typical full size HT whip)
• 1/2 wavelength 6m dipole is about 112"

Saftey

• shorting large batteries is dangerous (2022 T0A01) possibly causing fire, burns, or explosions
• current through the body
  • may cause involuntary muscle contractions
  • may cause burns
  • may disrupt electrical functions including the heart
• US 3wire 120v cable: black=hot green=ground white=
• fuses and circuit breakers can help prevent overloads; replacing a small fuse with a larger fuse could defeat this and cause a fire
• improve electrical saftey by guarding against shock by
  • using 3 wire cords and plugs
  • connect everything to a common ground; star net
  • use mechanical interlocks on high voltage circuits

Supplemental topics

• satellites
• paid exceptions: 97.113(a)(3)
  1. emergency disaster work and practice
  2. trader's net
  3. teacher at an educational institution using an amateur station for teaching
  4. club station that operates at least 40 hours a week on at least 6 MF+HF bands ... schedule published 30 days in advance ... bulletins and telegraphy practice (W1AW)
• history
  • pre-1910: spark gap
  • 1910 regulation: commercial use, Titanic
  • WW2
  • FCC/ARRL vs ITU / IARU
  • Hiram Percy Maxim
  • W1AW