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Antenna pattern measurement refers to the determination of the radiation pattern of an antenna under test (AUT). It is the measurement of the relative magnitude and phase of an electromagnetic signal re-ceived from the AUT. Al-though highly directional.
OW ELEVATION ANGLE(a in Fig, 6). Therefore, to judge antenna performance, it is more useful to have an antenna pattern showing the radiation at 30. egrees or more above the horizon. Figure 8 is a diagram showing the signal strength (represented by vectors) radiated from a typical half-wave dipole anten.
THE HAND-HELD RADIO ANTENNA DILEMMA – 1 – •Small radio chassis present a specifically difficult challenge to shielding the electronics and providing adequate counterpoise. •Internal construction and frame of higher-end commercial radios provided internal circuit shielding/isolation and significant metal frame structure (green outline.)
Antennas radiate (or receive) because electrons are accelerated (or are caused to accelerate) in the antenna’s elements. Radio or electromagnetic waves are both an E- (electric) and H- (magnetic) field. Electrons move parallel to E-fields.
Antennas & Projects 20.1 ANTENNA BASICS very ham needs at least one antenna, and most hams have built one. This chapter, by Chuck Hutchinson, K8CH, covers theory and construction of antennas for most radio amateurs. Here you’ll find simple verticals and dipoles, as well as quad and Yagi projects and other antennas that you can build and use.
The antenna selection chart in Fig. 66 gives some general guidelines for the choice of a suitable antenna for a given type of service according to the required distance range. Two different categories are considered: short distance and medium/long distance services.
as practical field expedient wire antennas. Review of the characteristics and radiation patterns of these antennas should allow the selection of the proper antenna for a specific circuit. A VHF antenna selection matrix is provided to assist the operator in selecting a suitable antenna for the desired VHF circuit. VHF.
