Codan Radio Transportable Radio Systems User Guide - Manual (Page 8)

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2.6.4 Enclosure
Depending on the nature of the Transportable Radio deployment the enclosure can be critical to the success or failure
of your system. If the enclosure is not sealed to the outside world, and the deployment will be in harsh weather con-
ditions with high levels of rain and dust exposure, then eventual failure of the system is likely.
There are a variety of enclosures available depending on your requirements:
• Aluminum Cases – These cases are very rugged and capable of air-tight ratings for the harshest of wet environ-
ments. These cases are also a good option for outdoor deployments such as forest fi re fi ghting or search and
rescue. Pressure release valves enable the cases to be transported in airplanes without pressurization.
• Polyethylene Cases – Offer a wide selection of sizes (briefcases, suitcase) with options such as pull-out handles and
roller wheels. Ideal for sub-urban and urban deployments.
• Polyethylene Rack Mount Cases – Larger versions of the polyethylene suitcases. These cases typically have entire
racks inside for mounting large communications systems such as multi-agency/multi-band systems or Transport-
able Trunked systems with multiple channels. Typically they are for very heavy equipment and require more than
one person to lift. Ideal for permanent mounting inside vehicles or mobile command centers.
2.6.5 Power Supply
The fi nal critical part of the Transportable Radio is the power supply. An analysis of the possible deployment scenarios
needs to be done prior to specifying the desired power source. Common power supplies used for Transportable
Radios include:
• AC Power – very simple to connect to, just plug the repeater into the “wall” and turn it on. This is only appropriate
for some applications as even urban deployments can fi nd a system with only AC power very limiting in where it
can be deployed. Either that or get a very long extension cord…
• Generators – gas or diesel generators can be used. These offer either an AC or DC output. Capable of very high
output powers, the big issue here is supplying fuel.
• Battery Power (Internal or External) – Very simple to operate, just turn on the repeater. However internal batteries
mean the repeater is heavier and has a shorter run time since only small batteries can be used. By adding a second
case to the repeater system, signifi cant increases in run times can be achieved as the external battery can be much
larger than its internal relative. However, a second case adds size and weight. Users of the system must always
remember to recharge the batteries between uses and the repeater must be very effi cient with its current draw.
• Solar Powered – By adding a solar panel to the repeater, it is possible to achieve extremely long run times. This is
very helpful for deployments that will be for an undetermined amount of time such as a Natural Disaster recovery
or Forest Fire. This solution adds a third case to the deployment however and again the repeater needs to be very
effi cient with its current draw.
• Wind Generators – can provide power in remote locations for long periods of time as a supplement to solar and
battery systems.
2.7 Summary of Requirements
A transportable radio system is intended to provide radio coverage on a temporary basis in an area not normally
served or to replace an existing radio site that has gone out of service. As such there are 4 key issues to keep in mind
in selecting your Transportable Radio System:
• Features – What are the essential features the radio system must provide?
Will the radio be conventional or trunked?
Number of channels required?
Will it operate in analog, P25 digital, P25 digital encrypted mode or all?
What frequency band(s) are you using?
Desired coverage area and transmit power required?
• Ease of Deployment – Where will the system be set up?
Source of power?
Setup time – minutes / hours?
Total weight and size – number of people for setup?
Type of transportation required (hand carried or in a helicopter)?
Type of Enclosure — Outdoor / Indoor, Visible / Stealth?
• Operation – Who will set up and operate the system?
Level of training required?
Linked to the existing radio network?
Ease of repairing a failure?
Can the system be reconfi gured?
• Affordability – What will the system cost over its operational life?
Initial cost?
Power costs?
Maintenance and service costs?
Expected operational life?
2.8 The trade-offs of a practical solution that meets your needs
The most important thing to remember when choosing the key features for your Transportable Radio as summarized
above is that there are always trade-offs. For example, a system cannot be extremely small AND be high power at
the same time. By going small the system cannot accommodate amplifi ers or large power supplies.
Small Size Low Power Output, single channel, few options
Easy to use Few options, less fl exible
Maximum coverage/penetration High-power required, therefore large size
Multi-Channel Requires large custom fi lter or two antenna
Multi-Band
Each band requires its own repeater and duplexer, therefore this system
will be larger the more bands that are required
Internal Battery Weight, batteries are heavy
Long deployments Additional power sources required such as battery banks or solar power
Priority Trade Off
Polyethylene Case
Polyethylene Rack
Mount Case