I. PART: REGULATIONS (Legislative framework)
1. Definitions and basic terms
Amateur service: A radiocommunication service intended for self-education, mutual communication, and technical study, conducted by amateurs (licensed individuals) who are interested in radio technology purely as a personal hobby and without financial interest.
Amateur satellite service: Same definition, but uses space stations (satellites) for signal transmission.
Amateur station: A set of transmitting and receiving equipment (including antennas and accessories) necessary for the operation of the amateur service.
2. International rules (ITU and Regions)
Article 25 of the ITU Radio Regulations: States that amateur radio broadcasting must be conducted in a language understandable to others (clear speech), prohibits the broadcasting of music, advertisements, and coded messages (except for technical abbreviations).
ITU Regions: The world is divided into three regions. Slovakia belongs to Region 1 (Europe, Africa, Russia, Middle East). Region 2 includes America, Region 3 Asia and Oceania. Differences are mainly in frequency allocations (e.g., the 7 MHz band is wider in Region 2).
European cooperation (CEPT and ECC)
ECC Recommendation (05)06: Defines 'Novice Radio Amateur Licence' (Class N). It allows amateur radio operators with this class to temporarily transmit in other CEPT countries that have adopted this recommendation without the need to apply for a local license (usually up to 3 months). When transmitting abroad, the prefix of the respective country is added before the own call sign (e.g.
OE/OM3XXXin Austria).
4. Licensing process in Slovakia
Licensing authority: Office for Regulation of Electronic Communications and Postal Services (Regulatory Office).
Application for a license: Can be submitted by a natural person (from 14 years old with the consent of a legal representative) or a legal entity. A certificate of successful examination must be attached to the application.
Operator classes:*Class N (Novice): Entry level with limited power and bands.
Class E (Extra): Full license (HAREC). Transition from N to E requires successful completion of an additional exam on more advanced techniques and regulations.
Validity of the license: Standardly 10 years, it is possible to apply for an extension. The license expires upon the death of the holder, revocation by the authority (in case of gross violation), or expiration.
5. Operational provisions and log
Responsibility: The holder is responsible for the operation of the station. A legal entity must designate a responsible operator.
Station log (Log): Mandatory document. It must contain: date, time (UTC), frequency (band), type of operation, call sign of the counterpart station, and transmitted/received report (RST). Today, electronic format is preferred.
Prohibited broadcasting: It is prohibited to broadcast messages for third parties (except in emergency situations), to use vulgar expressions, to play music, or to disrupt other services.
6. Technical parameters of class N (SK)
In class N, selected segments of bands are allowed (e.g. part of 80m, 40m, 20m, 15m, 10m on HF and entire bands 2m and 70cm on VHF). Maximum power is limited (usually 100 W on selected HF bands and lower power on VHF/UHF according to the current general authorization).
II. PART: OPERATION (The Art of Communication)
1. Spelling table (International)
For an amateur radio operator, it is essential to master the ICAO phonetic alphabet:
A – Alfa, B – Bravo, C – Charlie, D – Delta, E – Echo, F – Foxtrot, G – Golf, H – Hotel, I – India, J – Juliet, K – Kilo, L – Lima, M – Mike, N – November, O – Oscar, P – Papa, Q – Quebec, R – ROMeo, S – Sierra, T – Tango, U – Uniform, V – Victor, W – Whiskey, X – X-ray, Y – Yankee, Z – Zulu.
2. Q-codes and abbreviations
QSO: Connection
QTH: Station (location)
QRG: Frequency
QRM: Interference from other stations
QRN: Atmospheric noise (static crackle)
QSL: Confirmation of connection (card)
QSY: Change of frequency
73: Greeting (Respectfully)
3. Identification and call signs
Structure: Prefix (country, e.g. OM for Slovakia), Number (region, e.g. 3), Suffix (1 to 3 letters, e.g. ABC). Full call sign:
OM3ABC.Identification: The station must identify itself at the beginning and end of the connection, and every 10 minutes during longer sessions.
4. RST System (Report)
Used to assess signal quality:
R (Readability – clarity): 1 (unintelligible) to 5 (completely intelligible).
S (Strength – power): 1 (very weak signal) to 9 (extremely strong).
T (Tone – tone, only for CW): 1 (very bad) to 9 (pure tone).
Example: "You are giving me a report 59" means that I hear you excellently.
5. Propagation of radio waves
Short waves (SW): They reflect from the ionosphere (layers D, E, F1, F2). This allows for connections beyond the horizon (DX). Quality depends on the 11-year solar activity cycle. Lower bands (80m) work better at night, while higher bands (20m, 10m) work better during the day.
Very high frequency (VHF): They propagate directly (line of sight). Range is increased repeaters (repeaters) located on hills. Special conditions: Tropo (atmospheric inversion), Es (sporadic E layer – reflections in summer over long distances), Aurora (reflection from the aurora).12
III. PART: ELECTRICAL ENGINEERING (Basics and Safety)34
1. Basic quantities and Ohm's law56
In electrical engineering, we work with the relationship between voltage, current and resistance.
Ohm's law is a fundamental physical law of electrical engineering that expresses the relationship between voltage, current, and resistance in an electrical circuit. The law states that the electric current flowing through a conductor is directly proportional to the voltage and inversely proportional to the resistance.
Basic formula:
U = R × I
Derived formulas:
- I = U / R (current)
- R = U / I (resistance)
Where:
- U – voltage (volt, V)
- I – current (ampere, A)
- R – resistance (ohm, Ω)
This law applies to ohmic conductors at constant temperature and is named after the German physicist Georg Simon Ohm.
P is power in watts. For class N, it is important to know how to calculate, for example, the required current for a source if we know the power and voltage (typically 13.8 V).
2. Components and their functions
Resistor: It resists current, reduces voltage.
Capacitor: Stores electric charge, blocks direct current but allows alternating current (high frequency). Unit: Farad [F].
Inductor (Inductance): Resists alternating current. In combination with a capacitor, it forms a tuned circuit (resonant circuit) that determines the frequency of the radio.
Diode: Allows current to flow in only one direction (used in rectifiers).
Transistor: Basic element for amplifying signals or generating oscillations (oscillator).
3. Amateur radio station (Blocks)
Receiver (Superheterodyne): The signal from the antenna is in the mixer combines with the signal from the oscillator, creating an intermediate frequency that is easier to amplify and filter before detection (demodulation) to sound.
Transmitter: Microphone amplifier -> Modulator (inserts voice into carrier wave) -> Driver -> Power amplifier (PA) -> Low pass filter (to suppress harmonics) -> Antenna.
4. Antennas and lines
Dipole: The simplest half-wave antenna ($L = 142.5 / f$ [MHz]).
Yagi: Directional antenna with elements (radiator, reflector, directors) that focuses energy in one direction (gain).
SWR (VSWR): Standing wave ratio. Measured in with an SWR meter.. The ideal value is $1:1$. A value above $3:1$ can damage the transmitter because the energy is not transferred to the antenna but returns back to the radio as heat.
Coaxial cable: The most common feed with impedance $50 Ohms.
5. Interference (EMC)
The radio amateur must ensure that they do not interfere with TV, radio, or neighbors. The cause may be harmonic radiation (the transmitter also transmits at multiples of the frequency). The solution is filters (low-pass) and quality shielding.
6. Safety and protection
Electric shock: A current above 30 mA is already dangerous. In devices (especially older tube devices), voltages are hundreds of Volts. Capacitors can remain charged even after the device is turned off!
Grounding: The station must be properly grounded for safety and to reduce interference.
Lightning: Antennas are lightning rods. During a storm always disconnect antenna connectors from devices and remove them outside the building (or ground them outside).