The 8.1.7 Feedlines – Matching and Antenna Systems exam is meticulously designed to assess the comprehensive understanding essential for attaining the Spectrum Management Advanced Amateur Radio License. This exam delves into the nuanced application of antenna tuners and impedance matching circuits, fundamental for ensuring efficient energy transfer and optimized antenna performance in complex radio setups. By evaluating knowledge in these areas, the exam sets a foundation for advanced amateur radio operators to effectively manage and resolve the technical challenges associated with feedlines and antenna systems.

Furthermore, the examination explores the velocity factor and its critical role in feedline performance, alongside the theoretical and practical considerations of current and voltage distribution on antennas. These topics are vital for comprehending how different physical and electrical properties impact overall system functionality. Additionally, the exam addresses the significant effects that ground and elevation have on radiation patterns and angles, providing candidates with the insights needed to design and implement effective antenna systems tailored to specific environmental conditions.

This comprehensive evaluation is crucial for any amateur radio enthusiast seeking to elevate their technical expertise and achieve advanced licensing. It encourages a deeper investigation into the mechanics of antenna systems, pushing candidates to not only grasp theoretical concepts but also apply this knowledge in practical scenarios. Mastery of these subjects is indispensable for optimizing radio communication setups, ensuring candidates are well-prepared to tackle the challenges of advanced amateur radio operation and contribute to the amateur radio community with enhanced skill and confidence.

This exam is essential for advanced amateur radio operators aiming for the Spectrum Management Advanced Amateur Radio License, focusing on optimizing antenna systems through in-depth understanding of feedlines, impedance matching, and antenna design principles. It ensures candidates are well-prepared to address practical challenges in antenna setup and performance.

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Feedlines – Matching and Antenna Systems Exam

Advanced Amateur Radio – Feedlines – 8.1.7 Matching and Antenna Systems Exam

Tackle the key aspects of feedlines, matching, and antenna systems in this exam, crucial for advancing in amateur radio. It tests your ability to apply concepts like impedance matching and antenna feed arrangements effectively, preparing you for the Spectrum Management Advanced Amateur Radio License.

1 / 25

Category: Velocity factor, the effect of line terminated in non-characteristic impedances

A-007-002-007: What is a typical velocity factor for coaxial cable with polyethylene dielectric?

2 / 25

Category: Ground and elevation effects, vertical radiation (take off) angles

A-007-007-001: For a 3-element Yagi antenna with horizontally mounted elements, how does the main lobe takeoff angle vary with height above flat ground?

3 / 25

Category: Losses in real antenna systems, effective radiated powers

A-007-006-002: As standing wave ratio rises, so does the loss in the transmission line. This is caused by:

4 / 25

Category: Antenna tuner/transmatch, impedance matching circuits

A-007-001-009: What advantage does a pi-L network have over a pi-network for impedance matching between a vacuum tube linear amplifier and a multiband antenna?

5 / 25

Category: Antenna tuner/transmatch, impedance matching circuits

A-007-001-011: A Smith Chart is useful:

6 / 25

Category: Losses in real antenna systems, effective radiated powers

A-007-006-005: A transmitter has an output power of 200 watts. The coaxial and connector losses are 3 dB in total, and the antenna gain is 9 dBd. What is the approximate Effective Radiated Power of this system?

7 / 25

Category: Losses in real antenna systems, effective radiated powers

A-007-006-009: If a 3 dBd gain antenna is replaced with a 9 dBd gain antenna, with no other changes, the Effective Radiated Power (ERP) will increase by:

8 / 25

Category: Antenna feed arrangements – tee, gamma, stubs

A-007-003-009: A Yagi antenna uses a gamma match. The centre of the driven element connects to:

9 / 25

Category: Antenna tuner/transmatch, impedance matching circuits

A-007-001-005: What is a pi-network?

10 / 25

Category: Ground and elevation effects, vertical radiation (take off) angles

A-007-007-009: The impedance at the centre of a dipole antenna more than 3 wavelengths above ground would be nearest to:

11 / 25

Category: Antenna feed arrangements – tee, gamma, stubs

A-007-003-005: The driven element of a Yagi antenna is connected to a coaxial transmission line. The coax braid is connected to the centre of the driven element and the centre conductor is connected to a variable capacitor in series with an adjustable mechanical arrangement on one side of the driven element. The type of matching is:

12 / 25

Category: Losses in real antenna systems, effective radiated powers

A-007-006-010: A transmitter has an output of 2000 watts PEP. The transmission line, connectors and antenna tuner have a composite loss of 1 dB, and the gain from the stacked Yagi antenna is 10 dBd. What is the Effective Radiated Power (ERP) in watts PEP?

13 / 25

Category: Antenna feed arrangements – tee, gamma, stubs

A-007-003-002: What term describes an unbalanced feed system in which the driven element of an antenna is fed both at the centre and a fraction of a wavelength to one side of centre?

14 / 25

Category: Waveguide, microstrip lines

A-007-009-011: What precautions should you take before beginning repairs on a microwave feed horn or waveguide?

15 / 25

Category: Waveguide, microstrip lines

A-007-009-002: Which of the following is not correct? Waveguide is an efficient transmission medium because it features:

16 / 25

Category: Antenna tuner/transmatch, impedance matching circuits

A-007-001-010: Which type of network provides the greatest harmonic suppression?

17 / 25

Category: Current and voltage distribution on antennas

A-007-004-009: In a half-wave dipole, where does minimum voltage occur?

18 / 25

Category: Antenna feed arrangements – tee, gamma, stubs

A-007-003-003: What term describes a method of antenna impedance matching that uses a short section of transmission line connected to the antenna transmission line near the antenna and perpendicular to the transmission line?

19 / 25

Category: Radiation resistance, antenna efficiency, beamwidths

A-007-008-005: What is included in the total resistance of an antenna system?

20 / 25

Category: Current and voltage distribution on antennas

A-007-004-001: In a half-wave dipole, the distribution of _______ is highest at each end.

21 / 25

Category: Radiation resistance, antenna efficiency, beamwidths

A-007-008-001: What is meant by the radiation resistance of an antenna?

22 / 25

Category: Antenna feed arrangements – tee, gamma, stubs

A-007-003-004: Assuming a velocity factor of 0.66 what would be the physical length of a typical coaxial stub that is electrically one quarter wavelength long at 14.1 MHz?

23 / 25

Category: Losses in real antenna systems, effective radiated powers

A-007-006-006: A transmitter has a power output of 100 watts. There is a loss of 1.30 dB in the transmission line, a loss of 0.2 dB through the antenna tuner, and a gain of 4.50 dBd in the antenna. The Effective Radiated Power (ERP) is:

24 / 25

Category: Velocity factor, the effect of line terminated in non-characteristic impedances

A-007-002-009: Why is the physical length of a coaxial cable shorter than its electrical length?

25 / 25

Category: Antenna feed arrangements – tee, gamma, stubs

A-007-003-010: A Yagi antenna uses a gamma match. The adjustable gamma rod connects to:

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