Here we have 2 documents that many people have probably spent weeks putting together
and they don't even mention the solution to interoperability that SAFECOM has been
pushing for a number of years now. These 2 documents also keep pushing the
P25 standard as the sole source to the interop solution.
Let me ask a few simple questions here. First of all it looks like there are no plans to
take into account a complete trunking system failure. What happened to the
"NATIONAL INTEROPERABILITY" channels that are currently available across the
country. In most cases the need for any interop communications is over a short
distance. You don't need to tie up a trunking system to talk to other radios that are
only a few blocks apart. Also if you don't pre program all the incoming mutual
aid unit radios into the local trunking system, they can't use it anyway. This
adding all the surrounding agency radios to a trunking system becomes a major
accountability and control issue for the radio system manager. If the "NATIONAL
INTEROPERABILITY" channels are used, these are analog channels and any
radio can be communicated with. It doesn't have to be an expensive trunking
radio.
Second question I have here is in reading both of these documents, I ether missed
it or it wasn't there on how to solve the solution of linking the 800 MHz radios with
the VHF radios other than through a console patch. Why is a console patch the
only way to link non compatible radios? There are a few good gateway systems
on the market that can make links between non compatible radio systems and
they can even be on different bands. It is much cheaper to stay on the radios
you currently have than to go out and mass replace a fleet of radios because
some slick talking radio sales person convinced you this was the best way
to go.
Do you need all the features that a P25 radio system offers? Most radio users
will look at the cost of a P25 radio and look at the fancy features and come up
with the same answer. "It may be nice to have SOME of these features, but I
don't need them to communicate with". If this is the case, then why spend the
extra (big time) funds to move towards a P25 system. The cost can't justify
the end result except keep the radio companies happy.
Several states are currently in the process of looking at statewide interoperability
for all the state and local radio users. These states have figured out early on
that there will never be enough money available to switch out every public
safety agency radio in the state. The advantages don't justify the cost.
Another point to consider is that if you start loading up a trunking system
with all this "INTEROP" traffic, what is going to happen to the normal
communications that still has to go on. In many cases the trunking system
will fast run out of capacity and now your worse off than before. The
trunking system can only hold so much traffic.
The next issue that has been overlooked is what will happen if parts or the entire
trunking system crash, go off the air, towers fall down due to weather and the
likes. Now your back to square one again. It would be wise to have some
sort of plans that can maintain communications even if it may be on a simplex
channel and only portable radio to portable radio. I don't remember seeing
any plans or statements in either of the documents that take into account
a problem like this. It happens and happens much more frequently than
the radio companies want you to know about. You at least need some
plans to take this into account.
If you take a look at the Texas statewide plans, you might get some ideas
on a different point of view. Consider looking at some interop gateways
that use IP connections to link different locations and can share radio
channels. Depending on your funding there are a number of companies
to look at for gateways. There are what you could call 2 types of gateways
other than what the radio companies are trying to push. One is the small
field unit that doesn't use a network and only connects with from 2 to about
6 radios. No fancy controls, just cable to the radio (portable) and go. The
other kind is a network based unit. These gateways use the IP connection
to link different locations and radios together The have the ability to also
have remote computers for dispatch and control. One is made by JPS and
the other is made by Sytech Corp.
Trying to stay neutral on gateways, the main difference between the IP
connected systems is how they make the connection and function. The
JPS unit uses what is called a spoke and hub network. Here other gateways
are linked to a central hub unit. A separate network card is needed in the
central unit for each link that is needed. These cards go for around $2000
each list price. You also need a different IP address for each end of each link.
You have a limited max number of gateways that can be interconnected. You
have a limited number of remote control computers that can be connected. You
have a max ability to connect 24 radios from one gateway.
The Sytech Corp gateway uses a meshed network connection. In other words,
you only have one connection at each gateway. No extra cards to plug in, no
extra expense to make the network operate. The Sytech gateway has the ability
to use a remote computer (no limit on the number of computers) (no limit on
the number of interconnected gateways) to link and control a number of gateways
from the single IP connection. It also can utilize what some people call a
virtual control head on some selected radios and be able to remotely change
the radio channels or talkgroups from the remote computer. Basic gateway
has 8 or 16 channels. Optional to go to 32 channels before additional computer
hardware needs to be added. Works well over satellite links. National Guard
has 27 of these systems currently deployed in the field.
Just some food for thought before plans are laid and you get too far down the road
and then see that there might be an ops issue.
Jim
edge99 said:
