Page 1                                                            
                                                               
MISPuSa   Version 1. 3     3/1/92



PUBLIC SAFETY 
[Category: MIS] 

WHAT IS A PUBLIC SAFETY COMMUNICATIONS SYSTEM?
by Chuck Wood, WD6APP, County RACES Radio Officer
San Diego County Sheriff's Department Most people have no idea
how their police and fire departments communicate with the
officers in the field. As a Radio Amateur you probably have much
more knowledge about this subject than the average citizen. But
do you really know what goes on to protect the lives of our
citizens? 
Many years ago the FCC allocated three frequency bands for Public
safety. The first is commonly called Low Band and covers 30 to 50
MHz; the second, High Band, 150 to 174 MHz; and the third, UHF,
covers 450 to 512 MHz. More recently the 800 MHz Band has been
allocated but we will only discuss the first three in this
article.
Low Band is the best long range band and is in use in areas that
have large areas to cover because of its ability to curve over
hills and into valleys. It requires less radio sites because of
this. High Band is good for medium coverage areas and is used in
urban settings. UHF is much better for metropolitan coverage and
has much better penetration in cities such as New York, Chicago,
etc., where there are tall buildings.
Most systems use receivers that are located in remote areas and
are designed to enhance the coverage of the system. Since the
advent of small portable hand handhelds, this has become a must.
Some cities, such as New York, use hand handhelds totally and
have no radios mounted in the cars. This requires, at times, as
many as 20 to 30 receivers on a single frequency. These receivers
are commonly linked back to the main dispatch via high grade
phone lines or via microwave which can carry hundreds of voice
circuits. The City and County of San Diego each have such
microwave paths which are extensive and stretch for hundreds of
miles around the county and provide high quality radio coverage
for our Public Service Dispatchers. If you compare this to the
Amateur Radio repeaters we are used to using, you can see that
even though our ham repeaters are good, think of how good they
would be with multiple receiving and transmitting sites. This is
what is required so that your Public safety officers can pick up
their radios and get in at those critical times when lives are in
danger.  RB051 and 052 

UNDERSTANDING PUBLIC SAFETY DISPATCHERS & TELE-COMMUNICATORS 
I had the opportunity recently to present two seminars on the use
of Amateur Radio operators to the Western States Associated
Public-Safety Communications Officers conference in New Mexico.
They were attended by dispatchers, communications
managers/directors, engineers/technicians, and vendors. Most of
the dispatchers admitted that they knew virtually nothing about
radio hams and thought -- until now -- that they were the same as
CB'ers. I was stunned by the latter assumption until it dawned on
me that we hams -- and the served agencies -- seldom take the
time to brief or educate the public safety communications center
employees. Seek out opportunities to do this. Tell them how phone
patches work and how they may originate from outside their own
9-1-1 area. How hams must pass a rigorous examination. How
flexible ham radio systems are and how they can augment and
support the public safety mission in time of emergency. How it is
better to understand and work together before the emergency; that
any other time is too late. It is vitally important that any such
contact and liaison be done (a) by a ham familiar with public
safety communications and (b) completely in non-ham radio,
non-technical lingo. The latter is more important than the first.
-- RB118