Communication is a vital part of our infrastructure that we seldom appreciate
until it fails. Without it we lose connection with our loved ones and fall into the dark when
making important decisions.
Three levels of communication need to be maintained to provide proper levels of
information necessary for making wise decisions.
Local – Secure methods of communicating with your immediate group on or very near your
base of operations is vital to both safety and security. The desired range is within one half
mile and is used to relay information among your group members. FRS and MURS radios
are well suited for this but keep in mind that these frequencies are easily monitored by
others. Keep all communications discrete and brief. Kight radio offers the TONFA UV-985
dual band amateur hand-held radio for $89 that fills both local and intermediate comm
needs. At the 2W low power setting this radio is perfect for short range communicating.
Intermediate – Keeping alert to activity in your community is important. CB radios are
still in use and many will get back on the air to chat with their neighbors after the TV's and
cellular text fail. I would not recommend transmitting on these heavily monitored channels
but I would certainly listen for all the updates possible. CB radio might provide the first
alert to any organized assistance or locations to avoid due to social disorder.
A good scanner can keep you informed of local events and would be a wise investment.
For personal two way communication required up to twenty miles, a UHF/VHF amateur
radio with a good antenna can reliably reach another mobile radio or a hand-held radio.
Keep in mind that these are “line of sight” communications and physical obstructions limit
Long Range – Knowing what is going on in the rest of the world is always important as
well as providing a source of entertainment from music and news broadcast from distant
countries. Shortwave radios are not expensive but make sure the one you purchase will
actually pull in the signals you need. Shortwave listening is most active at night when
propagation is more favorable to radio reception. Don't purchase a radio and pack it away
for use later. Use it and learn how to run a 'long wire' antenna to improve reception.
Amateur radio in the HF bands will allow you two way voice connection over most of the
world. It's limits are that atmospheric propagation is never stable and changes radically
between night and day. With a good antenna and 100W of power, two way voice
transmissions are possible over very long distances. To understand its use a basic
understanding of radio propagation is necessary. Radio waves travel through our atmosphere
by two means: Ground wave (straight path from antenna to antenna); and Skywave (radio
waves from the transmitter are bounced off the ionosphere and received as they return to
Ground wave signals are limited by physical obstructions, the curvature of the earth, and
attenuation of radio signals at lower altitudes. The common limits of ground-wave signals is
about 30 to 50 miles, depending a lot on the height of the transmitting antenna.
Sky wave signals depend on the distance of the ionosphere from the earth at the time of
transmission. The atmosphere draws closer at night and expands during the day as a result
of solar radiation. When the ionosphere is too far away, radio signals reflect at an angle too
shallow to return to earth.
The difference between the limits of ground-wave transmission and sky-wave signal return
is called the skip zone. The skip zone is anywhere between 30 and 300 miles. This is a vital
area to maintain communications which lends importance to another HF propagation means
NVIS (Near Vertical Incidence Skywave) is a propagation plan that runs opposite to
conventional theory. To use the Sky wave for long distance communications an antenna
needs strong lateral emission that will hit the ionosphere at a shallow angle and bounce back
to earth. With NVIS the antenna is designed to radiate nearly vertical with as little radial
emission as possible. The signal reflects off the ionosphere and covers a circular area nearly
600 miles wide. NVIS is perfect for transmitting from a valley or otherwise obstructed
location. The best frequencies are often the noisiest for other means of radio communication
and the antenna design is intentionally low to the ground and easy to construct. Because of
the low horizontal emissions of NVIS communication it is difficult to locate the transmitter
by traditional directional finding (DF) equipment. NVIS is a reliable and stable
communication format with less fade and drift than traditional sky-wave methods.