The Comprehensive Guide to Class E Exams: From Regulations to Cutting Edge Techniques

Class E represents the pinnacle of amateur radio education. Unlike Class N, where basic knowledge is required, Class E assumes a deep understanding of physical processes, the ability to analyze complex schematics and master international legislation allowing operation almost anywhere in the world.

PART I: LEGISLATION AND REGULATIONS (Legal framework)

1. International guidelines (ITU and CEPT)

• Article 25 of the ITU Radio Regulations: It states that the amateur service is intended for self-education and technical study. It prohibits the transmission of messages on behalf of third parties (with the exception of emergencies) and the commercial use of bands.

• Division of the world (ITU Regions): Slovakia is in Region 1 (Europe, Africa, Russia). It is important to know the differences, for example in the 7 MHz (40m) band, which is wider in Region 2 (America) than here.

• Recommendation T/R 61-01 (CEPT Radio Amateur Licence): This is a key document for Class E. It allows the HAREC licensee to broadcast in any country that has adopted this recommendation without having to apply for local permission (short term).

• Recommendation T/R 61-02: It defines the exam syllabus and standard for issuing HAREC certificates, which ensures mutual recognition of licenses between states.

2. National legislation in the Slovak Republic

• Licensing authority: Regulatory Office (Office for the Regulation of Electronic Communications and Postal Services).

• Special professional competence: It is obtained by successfully passing the exam before the committee. The class E test is more demanding, especially in the field of radio engineering and mathematical calculations (decibels, resonance, complex impedance).

• Validity and loss of permit: The permit is issued for 10 years. The loss occurs in the event of a gross violation of international rules, non-payment of fees or a threat to the security of the state.

• Administrative offenses: The Authority can impose a fine for broadcasting without permission, interfering with other services or using unauthorized performances.

3. Technical and operating conditions

• Bands and performances: Class E has access to to all radio amateur bands (KV, VHF, UKV and above). As a rule, the maximum permitted power is in Slovakia 750 W (depending on the specific band and type of operation), which is significantly more compared to 100 W in class N.

• Station diary: Obligation to keep records of each broadcast. Class E emphasizes time accuracy (UTC) and correct recording of the type of operation (eg J3E for SSB).

II. SECTION: HAM RADIO OPERATION (Art of the Air)

1. Emergency and safety communication

• SOS and MAYDAY: SOS is used in telegraphy (CW), MAYDAY in voice traffic. A radio amateur is obliged to stop any activity if he receives an emergency call.

• ARES (Amateur Radio Emergency Service): A global network of volunteers ready to provide connectivity in natural disasters when normal infrastructure fails.

2. IARU Bandplans

Bandplans are not laws, but ethical agreements of radio amateurs associated in the IARU. They determine which parts of the band are reserved for telegraphy, digital modes or voice traffic. Compliance with band plans is the duty of every decent operator in class E.

3. Wave propagation and special modes

• Gray Line (Grey Zone): The area between day and night. Wave propagation along this line allows for unexpected long distance (DX) connections on the lower bands.

• EME (Earth-Moon-Earth): Using the moon as a passive reflection surface. It requires extremely sensitive receivers and high powers.

• Aurora a meteor scatter: Reflections from the aurora borealis or ionized meteorite trails. These phenomena are fleeting and require a quick response from the operator.

III. PART: ELECTRICAL ENGINEERING AND RADIO ENGINEERING (Theoretical basis)

1. Extended circuit theory

• Kirchhoff's laws: The law of currents in a node (the sum of currents is zero) and the law of voltages in a loop. Indispensable for analyzing complex connections.

• Power and rms value (RMS): Understanding the difference between peak voltage ($U_{peak}$) and effective voltage ($U_{rms}$). Calculation of the peak envelope power (PEP) in SSB modulation.

• Decibels (dB): Logarithmic expression of ratios. Antenna gain, cable attenuation or stage gain is calculated in decibels in Class E ($10 \cdot \log$ for performance $20 \cdot \log$ for voltage).

2. Components in detail

• Semiconductors: Differences between bipolar transistors (current controlled) and FET transistors (voltage controlled). Varicaps (diodes with variable capacitance) are used in tuned circuits and PLL syntheses.

• Tubes: Although they are a thing of the past in receivers, they are still used in power amplifiers (PA) due to their robustness. A Class E operator must be familiar with the principles of cooling and safe handling of high anode voltages.

• Integrated circuits: Operačné zosilňovače (OP AMP), logické obvody TTL/CMOS a základy mikrokontrolérov, ktoré riadia moderné stanice.

3. Digital signal processing (DSP)

Modern radio is no longer just about coils and capacitors.

• SDR (Software Defined Radio): After digitization, the signal is processed by software. Key terms: A/D converter, sampling rate (Nyquist) a FFT (Fast Fourier Transform) to display a waterfall of signals.

• DDS (Direct Digital Synthesis): Digital high frequency generation with extreme stability.

4. Antennas and power supplies

• Impedance matching: Maximum power transfer occurs when the impedance of the source (radio), line and antenna match (typically 50 Ohms).

• balun (Balanced-Unbalanced): Part for the transition between a symmetrical antenna (dipole) and an asymmetrical cable (coaxial). Prevents sheath currents that cause interference.

• Antennas yagi and parabolas: Directional antennas with high gain. The operator must be able to calculate EIRP (effective isotropic radiated power), which is the sum of radio power and antenna gain minus cable losses.

5. Measurement and security

• Oscilloscope and Spectrum Analyzer: Tools for controlling the quality of the transmitted signal (spectrum purity, suppression of harmonics).

• Security: With a power of 750 W, strong electromagnetic fields are created. Class E requires knowledge of safe distances and protection against RF burns. The grounding of the station must be separated for safety (lightning rod) and for HF functionality (counterweight).

Conclusion and recommendation for study

The E-class test is challenging, but it opens the door to experiments unavailable in the N-class—from bouncing off the moon to building your own power amplifiers. The basis of success is the combination of theory from physics with experience from practical operation.

73 and good luck with your exams!