Practical_Antenna_Handbook_0071639586

746 I n d e x
antenna tuning unit (ATU), 221–222, 533–544
for 1.8 MHz, 403–404, 413–414, 421
balun, 540–544
benefits, 533–534
circuit configurations, 534–540
for Âhigh-Âfrequency dipoles, 177, 187,
416
lumped-Âcomponent, 535–540
reactance cancellation, 534–535
remotely tuned, 534
shielding, 539–540
split-Âcapacitor network, 538–539
(See also tuning)
antipode, 65
aperture, 17, 471, 478
(See also effective aperture)
apex angle (longwire), 261–262
arcing, 315, 365
Armstrong oscillator circuit, 354–355
array factor, 153–159
arrays, 149–171
all-Âdriven, 149–161
broadside array, 151–152
broadside gain, 156–157
cardioid, 157–158
collinear, 156, 376, 430, 432
end-Âfire array, 152–153, 154–155, 215
fundamentals, 149–159
ground effects, 163–171
parasitic, 161–162, 277–314, 419,
434–436
phase shift, 485–487
quadrature phasing, 158–159
receiving, 161
side lobes, 156
Watson-ÂWatt Adcock array,
522–523
astronomy (See radio astronomy antennas)
atmospheric layers and radio propagation,
20–22, 38–44
atmospheric noise (QRN), 331, 389
atmospheric pressure, 9, 34
attenuation constant (α), 120
attenuation of radio waves, 15–17, 28, 36,
42–44, 61
attenuation in transmission lines,
119–121, 135–138, 447–449, 582–583,
585
attic-Âinstalled antennas, 364–366
auroral propagation, 75–76
azimuthal equidistant projection (See great
circle paths)
B
back lobes, 477
backscatter, 71
balanced transmission line, 110–111, 114
balun, 139–140, 196, 215, 302, 441–442, 445,
540–544, 629, 631–633, 636
current transformer wattmeter,
608–613
ferrite core, 540–544
multifilar windings, 540–541
multi-Âimpedance (tapped), 540–541
strain relief, 543
trifilar windings, 540
turns, 543–544
windings, 540–544
winding techniques, 542–544
bandwidth, 177–178, 200, 292, 316–319,
381–382, 711
beam antennas (rotatable):
cubical quad, 315–324
Moxon, 306–308
W8JK, 277
Yagi, 277–314
ZL-Âspecial, 264
beam vs. beamwidth, 278
beamwidth, 279, 476–477
bent dipole, 157, 200, 202, 306–308, 316, 416,
549–554
(See also dipole)
Beverage, H. H., 333
Beverage or “wave” antenna, 67, 182, 332–341
bidirectional, 339–340
cone of silence, 334
efficiency, 182, 332–333
feedpoint impedance and matching, 334,
338
grounding, 333–338
installation of, 333–338
insulators, 337
maximum effective length (MEL),
334–335
on the ground (BOG), 341
phased, 340
termination resistors, 336–337
testing, 338–339
bidirectional RDF patterns, 512–514