[KYHAM] KEN TRAINING for January 14,2002: Mobile Command Post: Design Issues

[Ron Dodson]

Last year we had some good discussion going on MCP layouts
etc.  Tony's article last week on FM seemed to be well
received.  Here is another offering from him on a subject he
should know well.  Thanks again Tony!
73,
Ron, KA4MAP


Mobile Command Post: Design Issues
Tony Whobrey, KC4JTV

When designing a mobile command post, there are many issues
to consider. This article will cover some of the more
important considerations.

The obvious first step is choosing a platform; a typical
choice is between a trailer and a self-propelled vehicle,
such as a van or bus. Former school buses are often
suggested as command post platforms, and are often readily
available. The drawback is high maintenance costs, which are
usually the reason that such vehicles were removed from
route service. For many, a trailer-based unit is the best
option, since it can be readily moved behind any suitable
vehicle. In contrast, if the bus or van-type vehicle doesn�t
start, repairs could take some time. Self propelled CP
vehicles are probably best left to large organizations with
in house maintenance staff and facilities.

The restroom and kitchen amenities that are often found in
more elaborate CPs offer obvious advantages. However the
frequently overlooked disadvantage is that such facilities
too often serve as a beacon to invite others to loiter
around your vehicle, causing your operation to eventually
resemble a break room or lounge. Excessive foot traffic in
and out of the CP is detrimental to smooth operation. If you
choose to include such facilities, it may be necessary to
formulate a diplomatic way to limit its use to that of your
own personnel.

When planning operating position(s), be sure to allow plenty
of space. Two positions with adequate room are far superior
to three cramped positions. The operator�s desk will rapidly
fill with logs, notes, pens, and the ever-present coffee
cup. If more than one operating position is planned,
headphone jacks will be needed at each position. It is
nearly impossible for two radios to be employed
simultaneously by separate operators in close proximity
without the use of headphones. A telephone will also be
needed at each operating position, unless your CP is very
small. Try to plan placement of positions in order to limit
foot traffic, as it should not be necessary to go thru the
op position, unless it is to access an adjacent op position.

Once you have decided on placement of the equipment, the
next issue is power for its operation. Current commercially
produced CP facilities usually power all of the
communications equipment from a common 12-volt source, since
most modern radio gear requires this voltage anyway. Several
vendors have 12-volt fluorescent lighting available, or for
those on a tight budget, auto type dome lights could be
used. Automotive �back up� or industrial-type floodlights
commonly used on construction equipment can light the
immediate area outside the command post.

A 12-volt bus can be used, fed by a battery bank with a
suitable charging system. Assuming 12-volt batteries in
parallel, a means should be provided to permit the removal
of a failed battery, while the remaining units continue to
provide power. For this reason a minimum of two batteries
should be employed. Redundant battery chargers are worth
considering if your equipment will require substantial
current. Be sure to install a voltmeter, so that the
charging system can be monitored. In the case of a
trailer-based unit, the tow vehicle might initially be used
to provide power, in order for operations to begin almost
immediately.

 Self propelled units will typically use the vehicles own
engine driven alternator, until AC power can be provided.
Commercial power or a portable generator can be used to
power battery charging equipment as the operation
progresses, as well as to provide power for heating or air
conditioning systems. If the generator has to be stopped for
fueling or repair, most of the operation can continue
without hindrance, using the continuously available battery
power during the interruption. For all but the largest self
propelled CPs, permanently mounted AC generators should be
avoided, because of their seemingly large maintenance
requirements.

Provide at least one permanently mounted antenna for each
frequency range you plan to use. The better quality antennas
sold for mobile use are generally fine for this application.
At least some of your radio equipment can be placed into
immediate operation with these antennas, and they are
usually adequate for short to medium range use. If the
command post can be set up on high ground, or operations are
in an area where most communications use repeater-based
systems, there may be no need to erect a larger antenna
array.

 When specifying radio equipment for your CP, consider the
purchase of a few FRS or similar license free radios. They
can be employed for short-range inter-agency communications,
as everyone�s radios may not be capable of operation on a
common frequency. In the initial set-up of your command
post, these units will be used while orienting antennas,
vehicles and the like. These small radios are best used as a
sort of �wireless intercom�, they are OK for distances up to
several thousand yards, and can be operated by anyone,
regardless of his or her level of technical expertise.

 Now that all the elements are in place for operation, one
more step can be taken to insure ease of operation. The unit
should be properly supported to prevent its shaking about
during use. The tires and suspension on even a large vehicle
will give somewhat when a person enters or exits; this
continual movement can be irritating to those who must
remain inside over long periods of time. Blocks, jack
stands, or wooden cribbing should be provided to support
your unit and eliminate most of this unneeded movement. A
small floor jack will make this job less taxing, as it
provides a substantial mechanical advantage over other types
and can be operated while standing.

 The eventual layout of your command post will evolve with
its use; this should be expected and planned for. Don�t be
discouraged if a design that sounds and looks good on paper
fails in actual use, as it is nearly impossible to forecast
the demands that actual deployment will place on your
equipment. After the initial use of your command post,
preferably in a non-emergency situation, critique its
performance. Don�t be afraid to modify it to suit the needs
of your own group, after all it is your home away from home.