April 2017 51
OPEN COMMUNICATION ; BY LOU FRENZEL W5LEF
Remember CB Radio?
First, most of you have heard of
the Citizens Band Radio Service. Back
in the day in the 1970s before cell
phones, CB was hugely popular, and
many cars and trucks sported those
ungainly eight foot whip antennas or
the shorter magnetic mount coil-loaded antennas.
It was great for short range
communications on the highway as it
allowed anyone to report traffic jams,
radar traps, and bad weather. It was
a good way for truckers to pass the
time by gossiping.
CB Radio is license-free, meaning
there is no need to get a blessing
from the Federal Communications
Commission (FCC). Just buy the
radios and talk. CB uses 40 channels
in the 27 MHz spectrum, amplitude
modulation (AM), four watts of power
on AM, and 12 watts if you use the
single sideband (SSB) version.
Range is generally restricted to
several miles, but it is still very useful.
With cell phones being ubiquitous
today, almost no one (except possibly
truckers) uses CB. However, it is still
an option available to you.
Recently, I tried to see what
activity there was on the CB channels.
I located my old RadioShack
handheld CB radio. I monitored
the popular channels 9 and 19 and
a few others, as well as initiated
a continuous scan, but found no
activity. I live in the suburbs away
from a major highway so that may be
I made a couple of transmissions
to generate some activity. Dead
silence. After several days of trying,
I gave up. CB is dead at least in my
area. Do any of you out there still use
GMRS is the Way to Go
The General Mobile Radio
Service is a technology like CB in
that it allows individuals to operate
radios for personal or business use.
Unlike CB, it does require a license.
However, the license does not involve
an exam and it is relatively easy to
get. (More about that shortly.)
GMRS operation takes place in
multiple channels in the 462 and 467
MHz UHF range. Table 1 shows the
main operating frequencies. Note that
some of the channels are shared with
the Family Radio Service (FRS) that I
will cover later.
GMRS radios use frequency
modulation (FM) with ± 5 kHz
deviation and maximum power levels
of five watts for handhelds and small
base stations and repeaters, and 50
watts for larger base stations and
repeaters. Those are effective radiated
power (ERP) output levels.
ERP is the actual transmitter
output power plus the effective
power boost from any antenna gain.
Antenna height is restricted to 20 feet
above the ground or above the roof
or structure to which it is attached.
As for transmission range — like
all radio — it varies. At ultra high
frequencies (UHF), transmission is
line-of-sight (LOS) meaning direct
from antenna to antenna. If the
antennas do not “see” one another,
transmission is blocked or at least is
our primary radio
device. We have
become addicted to
our phones, as today,
they are the do-all
device for voice, text,
emails, and Internet
access. However, did
you know that you
actually have more
options could come
in handy when your
cell phone is not as
convenient, out of
range, or not working
during an emergency.
Let me introduce you
to the General Mobile
Radio Service (GMRS)
and the Family Radio
Personal Radio Technologies
Here are some communications options
you may not know you had.