Codan-radio Radio Repeater Systems Training Guide Uživatelský manuál stáhnout pdf (Strana 31)

RADIO REPEATER SYSTEM | TRAINING GUIDE

Chapter 3: Repeater System Equipment Page 23

The antenna in Figure 3-3 is a “beam” or “yagi” and is usually used for linking purposes. You may see it

polarized in a horizontal or vertical position. A VHF yagi will be larger than a UHF yagi. A yagi provides

increased gain in one direction. A typical pattern is also illustrated.

Figure 3-3: Yagi Antenna

Another type used on links where a higher front-to-back ratio is required is the corner reﬂ ector antenna

shown in Figure 3-4.

Figure 3-4: Corner Reﬂ ector Antenna

Examples of antenna data and radiation patterns can be found in Appendix F.

Typical Horizontal Radiation

Pattern For Vertical Polarization

BEAM ANTENNA

+10°

0

-10°

DIPOLE

REFERENCE

dB RE l /2 DIPOLE

-10 -5 0 5 10-10-50510

Typical Horizontal Radiation

Pattern.

+10°

0

-10°

CORNER REFLECTOR

DIPOLE

REFERENCE

dB RE l /2 DIPOLE

-10 -5 0 5 10-10-50510

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