Begin forwarded message:
From: Andrew Seybold <andy@xxxxxxxxxxxxx>
Date: September 10, 2005 7:56:16 PM EDT
To: dave@xxxxxxxxxx
Subject: RE: [IP] communication networks for humans
I have several comments about public safety--first responder
communications since I am deeply involved in this.
1) There is, in the fire service, what is known as the Incident
Command
system. It says that the first on the scene becomes the incident
commander, as the incident grows and 'bosses' show up the IC is handed
upwards.
As the incident grows so does the command structure, it is quickly
divided into groups including incident control, logistics, and many
more, as the size of the incident continues to grow the teams are
splint
into divisions. One of the key principals of this system is that NO
ONE
ever has more than five direct reports to them, if they need more they
split the command structure yet again--
2) Public safety equipment is old (mostly analog FM) because these
departments do not have the money to upgrade. Many of the public
safety
systems I designed and sold in the late 1970's and 1980's are still in
use (by the way we did install mobile data terminals in those days in
many cities and counties).
3) There is a new digital standard for public Safety communications
developed by APCO, known as APCO 25 and most of the newer radios today
include the capabilities of both analog and digital communications.
But
since it is only for public safety the prices for the equipment are
very
high. But GSM, CDMA, WI-FI, WiMAX and other commercial technologies
cannot meet the needs of the public safety community.
4) Public safety channels are not contiguous, they are in the 30-50
MHz,
150-172 MHz, 450-470 MHz, on shared TV channels in the 470-512 MHz
range
as well as in the 800 Mhz band. There is 24 MHz of "new" public safety
spectrum coming (someday) in the 700 MHz UHF TV band but who really
knows when. The feds have their own channels, again spread out over a
lot of spectrum and have duplicate systems in most cities. In fact the
FBI and SS have systems that rival the locals but will not permit
local
use of their channels even during a major emergency.
5) Command and control of a net is normally handled by the dispatch
center-which coordinates traffic on the channels. Normally in a major
event there is a command and control channel that permits the
bosses to
communicate directly with the command center (dispatch center), and
then
the orders are relayed on working channels including additional wide
area and simplex channels as needed. Note--a dispatcher can "normally"
handle about 60 individual units on a single channel, not more
which is
why large cities have many channels and they are usually divided into
sectors.
6) There are common fire and public safety channels in at least one
band
(150 Mhz) which every unit is supposed to have in their radios (Fire
White for example which is 154.280 MHz), and the police have Clemars
also in the same band.
7) There is a move to update the public safety radios--one proposal is
to use the 700 MHz band to supply radios to local, state, feds and
have
these radios programmed over the air as people and equipment arrive
at a
scene.
8) Data is done either using their own channels or on public networks
there is no consistency here at the moment and the "new" Apco 25
channels are so narrow that data services require a number of channels
to be aggregated in order to provide even slow data speeds.
9) Secondary and admin communications is usually off-loaded to public
networks such as Nextel's Direct Connect service but often times in a
major event these channels--which have No priority are jammed.
10) Commercial wireless technology, in most cases, will NOT work for
these agencies because they need one-to-many and dispatch
capabilities,
they need wide-area systems so everyone can hear everyone else, and
they
need incident simplex channels for local coordination.
11) Many dispatch systems are making use of IP routers to tie together
two or more different PS channels during an event. This occurs at the
dispatch center BUT it means that a single conversation is taking up
more than a single voice channel.
12) While public safety communications frequencies are coordinated by
volunteers to minimize interference between departments and areas,
many
departments are OUT of capacity and have been waiting for years for
one
or two extra channels, while gobs of unlicensed spectrum has been
handed
out for Wi-Fi and now WiMAX systems--ok, ok, mesh networks? Tell me
how
to do that over all of these channels, tell me how to coordinate
all of
this without any money to make it happen.
13) During major incidents the public networks are so jammed as to be
useless, and John J. Citizen has as much priority to get a call
through
as the fire chief in charge of an incident.
14) The ONLY way to fix all of this is with money and a vision, and
that
vision will take YEARS to accomplish--by the way, there is a reason
that
the CHP, for example, are still using 42 MHz (yes 42 MHz) for their
systems, if they moved to 800 MHz they would need hundreds, yes
hundreds
of new radio sites and still would not be able to provide radio
coverage
in the mountains and rural areas--the higher you go in frequency the
less range you can cover--
Public Safety communications is the most miss-understood and
maligned of
all of the radio services and it is because few understand the
issues--in closing one more point--I guarantee that the public safety
systems, when up and operating cover their areas better than ANY
public
network--they have been designed to do that over the years--inside,
outside, and everywhere, they HAVE to provide that level of coverage.
They are all backed up with emergency power and batteries, redundant
circuits and the best in tower locations. But it is a fact of life
that
generators and batteries do not work very well under water.
Many a police officer has been asked if they had to do without
their gun
or their radio which they would pick and the answer is always, take my
gun, leave me my radio!
Just my three or four cents
Andy
-------------------------------------
You are subscribed as gerry-faulhaber@xxxxxxxxx
To manage your subscription, go to
http://v2.listbox.com/member/?listname=ip
Archives at: http://www.interesting-people.org/archives/interesting-
people/