Radio Shack Pro-2032 - Page 20

As a general rule on VHF, most activ¬
ity is concentrated between 153.785
and 155.98 MHz and then again from
158.73 to 159.46 MHz. Here you find
local government, police, fire, and
most emergency services. If you are
near a railroad or major railroad
tracks, look around 160.0 to 161.9 for
signals.
One very useful service is the Envi¬
ronment Canada Weather Radio’s
continuous weather broadcasts.
These broadcasts contain weather
forecasts and data for the area
around the station, plus bulletins on
any threatening weather conditions.
These stations use three frequen¬
cies—162.40, 162.475, and 162.55
MHz. In most areas of the country,
you can receive one or more of these
frequencies.
You can hear commercial aircraft
transmissions between 118 and
136.975 MHz. Military aircraft oper¬
ate between 225 and 400 MHz.
In some large cities, the UHF bands
are used for emergency services.
Here, most of the activity is between
453.025 and 453.95 MHz and be¬
tween 456.025 and 467.925 MHz.
In the UHF band, frequencies be¬
tween 456.025 and 459.95 MHz and
between 465.025 and 469.975 MHz
are used for mobile units and control
stations associated with base and re¬
peater units that operate 5 MHz lower
(that is, between 451.025 and 454.95
MHz and between 460.025 and
464.975 MHz). This means if you find
an active frequency inside one of
these spreads, you can look 5 MHz
lower (or higher) to find the base sta¬
tion/repeater for that service.
A newer technology is now available
that uses the 800 MHz band for many
services. Trunked radio, introduced to
business systems in 1975, is now
used by public safety agencies. With
up to twenty channels available, the
transmitter automatically selects an
unused frequency each time it is acti¬
vated- Several agencies can share
such a system without interfering with
each other. This system can provide
secure communications for selected
units, with unselected units unable to
hear the message.
Frequencies in different bands are ac¬
cessible only at specific intervals. In
the VHF-Lo, HAM, Government, and
VHF-Hi bands, frequencies are avail¬
able in 5 kHz steps. In the aircraft
band, frequencies are available in 25
kHz steps. In all other bands, fre¬
quencies are available in 12.5 kHz
steps. Your scanner rounds the en¬
tered frequency down to the nearest
valid frequency. For example, if you
try to enter 151.473, the scanner ac¬
cepts this as 151.470 MHz.
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