28
This configuration allows operation from 1.8 to 30 MHz and the SG-230 will
tune and load all frequencies well below a ratio of 1.1:5 VSWR. Directivity will
be high from 3 to 12 dB depending upon the frequency. If this is a problem,
two loops at 90 degrees can be installed to communicate at 90 degrees off
direction of the first loop antenna. Loop antennas are low noise antennas.
However, because they are used in apartments and urban cities, high industri-
al noise can be expected. Avoid using neon of fluorescent lights within 50 feet
of the loop antenna, they may completely jam one or more frequency bands.
F
Fiig
gu
ur
re
e 5
5..1
12
2
S
Sm
ma
allll llo
oo
op
p a
an
ntte
en
nn
na
a ((3
3 x
x 4
4 ffe
ee
ett))
Loop antennas of much larger sizes can be used, however, please remember
that while the low frequency operation of such antennas may be quite good,
the larger antennas may not work well at very high frequencies when located
in a plane parallel to the earth. This is because large loop antennas generally
radiate their maximum lobe (field strength) at right angles to their plane.
This means that a large loop, say 60 feet on a side, mounted 20 feet above the
ground would radiate much of its energy upward. While during the day this
would work well for close in communications, longer distances would be
achieved with the loop mounted vertically. The vertical loop antenna of one
quarter wavelength is the basis of the "quad" type directional antenna.
Loop antennas represent a DC short circuit and for this reason are much less
susceptible to noise than are other kinds of antennas. In certain residential
and industrial areas where high noise levels occur, the loop antenna may pro-
vide a substantial improvement in both receiving and transmitting perfor-
mance at very little cost.
SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA 98005 USA
P.O. Box 3526, 98009 Fax: 425-746-6384 Tel: 425- 746-6310 or 1-800-259 7331
E-mail: [email protected] Web site: http://www.sgcworld.com
© 1998 SGC Inc
SG-230 Manual
Pegs or Nails
SG-230 PRO SMARTUNER
Cable to Radio
Use 6-8 turns of #16 or larger wire which is
insulated for high voltages. No spacing
between turns. Use a total of 70-90 feet of
wire.
Building wall
SG-230 SMARTUNER