CCNA Wireless Official Exam Certification Guide part 12 is a best of breed Cisco® exam study guide that focuses specifically on the objectives for the CCNA® Wireless IUWNE exam. Senior instructor Brandon Carroll shares preparation hints and test-taking tips, helping you identify areas of weakness and improve both your conceptual knowledge and hands-on skills. Material is presented in a concise manner, focusing on increasing your understanding and retention of exam topics. | 82 CCNA Wireless Official Exam Certification Guide 180 Figure 5-16 E-plane of the AIR-ANT-2485P-R Yagi Antenna The yagi antenna is a directional antenna that offers a very direct radiation pattern. Sometimes you see these mounted above doorways to cover a long hallway. You can also put a number of them side by side on a wall to cover a large open space such as a warehouse or convention center. Yagi antennas are sometimes called Yagi-Uda antennas after their two creators. Note For more information on the history of the Yagi-Uda antenna see http en. wiki Yagi_antenna History. Yagi antennas have a butterfly effect that is an effect of their polarization as illustrated in Figure 5-17. You can clearly see the butterfly-type pattern in the figure. Notice that there is also some coverage on the back side of the antenna even though it is designed as a directional antenna. This fact can be useful if you want to test under the antenna. Figure 5-18 shows the 10-dBi yagi one of the yagi antennas offered by Cisco. Although it is enclosed in an aesthetically pleasing cylinder the antenna inside is a comb that resembles old UHF television antennas that you used to see on the roofs of houses. Chapter 5 Antenna Communications 83 28-80 Degrees at GHz Key Topic Figure 5-18 AIR-ANT2410Y-R Figure 5-19 shows the AIR-ANT1949 another yagi antenna offered by Cisco. This yagi is a high-gain antenna at dBi. Its H-plane and E-plane are shown in Figures 5-20 and 5-21 respectively. Table 5-6 shows the details of the AIR-ANT1949 yagi. Figure 5-19 AIR-ANT1949 Yagi 84 CCNA Wireless Official Exam Certification Guide Key Topic Table 5-6 AIR-ANT1949 Yagi Frequency range to GHz Gain dBi Polarization Vertical H-plane 30 degrees E-plane 25 degrees Antenna connector type RP-TNC Mounting Mast wall mount This connector type is covered later in the section Antenna Connectors and Hardware. Figure 5-20 H-plane of the AIR-ANT1949 .
