EXPLORING RADIO
COMMUNICATIONS
by Roger Vargo, N6YDT |
Exploring the outback by foot or by vehicle is an
inherently dangerous way to have fun. Isolation is great - right up to the
moment when you stumble and break an ankle. Backroads are scenic until your
vehicle becomes enveloped in the environment and hidden from the other vehicles
in your traveling group. Some form of radio communication should be considered
basic equipment.
Citizens Band (CB) radio is the first choice for most
backcountry travelers. The equipment is available from mass retailers such as
KMart, Target or Radio Shack. CB radios are simple to operate, require minimal
technical skills and no license.
Advertising hype not withstanding, all CB
radios have two things in common. They are restricted to 40 preset channels and
4 watts of power output. Useful range varies from less than one mile to
thousands of miles depending upon atmospheric conditions and the number of
other users on the channel. Many operators flaunt the rules and run hundreds or
thousands of watts of transmitter power causing unnecessary channel congestion
well away from their local area.
Channel 9 (27.065 MHz) is monitored for
emergency messages in some areas by members of the volunteer REACT (Radio
Emergency Associated Citizens Teams) organization. One of the few remaining
federal rules pertaining to CB radio restricts Channel 9 to emergency or
informational use only. Along major highways, truckers can be heard talking on
Channels 15,17, and 19.
Cellular phones, those oblong protuberances that
seem to grow from the ears of BMW drivers, are unreliable away from major
population centers. Their technology is based on low power radios linked
to
BACKROAD EXPLORERS NEWSLETTER |
small geographic coverage units
called "cells". Even in a fully functional cellular environment, casual chatter
between vehicles is impractical and expensive. With instant 911 access,
cellular phones are excellent for emergency situations-as long as they occur in
a cellular coverage area.
Commercial business band radios offer many of the
benefits and drawbacks of CB and cellular units. They are easy to use, with a
restricted number of channels. They are somewhat expensive, require prior
licensing, and may not work when away from the system's prime coverage area
unless there is a direct or car-to-car mode. These radios can offer excellent
audio quality and coverage.
Amateur (ham) radio is a flexible alternative to
other radio communication services. Operating in the very high (VHF) and
ultrahigh (UHF) areas of the radio frequency spectrum, these radios can provide
vehicle to vehicle as well as wide area coverage through mountain top
repeaters. A repeater is a special type of radio, usually located on a tall
building or mountain, that receives a signal on one frequency and
instantaneously retransmits it on another frequency. Repeaters provide coverage
on metropolitan freeways as well as backroad byways. Some repeaters are on the
amateur bands. There are thousands of repeaters across the country in the
VHF/UHF amateur bands. Many are open to all licensed amateurs to use for free.
Talking direct (simplex) is the preferred mode for localized conversations.
Amateur radio frequencies in the VHF and UHF bands are usually less crowded
than their CB counterparts. This can be attributed to more frequencies, fewer
operators and the way the signals affected by the atmosphere.
Equipment for
the amateur bands is more complex and expensive than CB gear. It is also more
powerful. A "typical" mobile radio takes up about the same amount of space as
a |
mid-size CB, yet has a power output
of 25 to 50 watts. Handheld radios are available with up to 5 watts of transmit
power and all of the functions of their mobile counterparts. Modern radios
allow frequency and other information to be programmed into memory channels.
Once this is done, actual operation is about as easy as changing channels and
adjusting the volume on a CB. The ability to send and receive Morse code is no
longer a requirement for one class of license. Called the "no-code" Technician
class, its licensees have full privileges in the bands most used for mobile
communications. Successful completion of two written, multiple choice tests is
all that is required for licensing. Licenses are good for ten years and are
renewable upon application.
All possible test questions and answers are
available in study guides. One such guide, available from Radio Shack stores,
is the NEW NO-CODE TECHNICIAN CLASS by Gordon West (#62-2413). The written
tests total 55 questions and are administered by volunteer examiners. There is
usually at least one exam session held each weekend in the metropolitan Los
Angeles area.
Many local clubs offer free periodic licensing classes for
beginners. Several instructors offer weekend "schools" that charge in the $150
range. Students are taught all the information they need to pass the written
tests, which are given on the last day.
Frequency modulated (FM) voice is
the common mode of operation in the VHF/UHF amateur bands. It offers superior
clarity and signal capture over amplitude (AM) or single sideband (SSB)
modulation used in CB radios. Other modes of operation are also available to
no-code technicians. These include television, various forms of radio teletype
and satellite operations.
Your link to safety is a two-way radio. To
paraphrase the American Express motto, don't leave home without one. |