Major Events and Emergencies – Protect and Strengthen Your LMR System

Preparing for Major Events and Emergencies - Download the GuideMajor Events and Emergencies is the next article taken from the new guide on how to protect and strengthen your LMR system. If you missed the previous chapters you can read those here.

The Tougher LMR Networks guide investigates every aspect of wireless communications, and considers how operators might make their LMR systems more resilient.

You can also download the full guide and read it on the go.

Major Events and Emergencies

This is when your system and your people must perform at their most effective, often at peak capacity and for extended periods of time. You need to invest enough to stay on air, ensuring power to your sites throughout.

Sizing your system for “The Big One”

A thorough risk analysis needs to be carried out periodically with a trusted consultant, vendor or adviser, but there are some guiding principles for planned events (such as sports events and political conventions), unexpected emergencies and natural disasters.

One simple rule is that your system capacity should be roughly three times your normal weekly “busy hour”. Traffic statistics or data logging records will give you an indication of what that figure is.

However, a small rural organization is unlikely to need that much capacity regardless of circumstances – they may have few users and emergencies may be less complex, with potentially less impact.

On the other hand, an urban area in an earthquake zone, with commercial centers, sports and education facilities and transport hubs may justify more than the “busy hour x 3” capacity rule.

Power at sites

One of the biggest risks to your communications is also one of the simplest. Statistically, the most common cause of communications failure is power at your radio sites. Backing up your power supplies with dual redundancy can prevent communications outages during weather events, particularly where towers are at elevation, remote or inaccessible during winter.

Remember that a power outage may also mean your fuel supplier may not have power to pump fuel, so ensure backup supplies on site.


While your investment depends on location and risk assessment, there are some basic principles you should build in to your day-to-day planning to maintain communications in any event.

  • Eliminate single points of failure at system design stage.
  • You will lose power to your system – plan for it with dual redundancy (AC then battery then generator).
  • Estimate how long different scenarios may leave you without power.
  • Invest enough to stay on air through critical events, ensuring power to sites throughout.
  • In a major disaster, telephone systems (especially cell phone systems) frequently fail.
  • Plan for a scenario in which your computer systems are not available.

an event can hit at anytime - Snow StormPlanning

Whatever sector or industry you operate in, planning for critical events on a daily basis is much better than figuring it out when you are under duress!

To predict emergency coverage and performance requirements, look first to local history – are you at risk from floods, hurricanes, forest fires, blizzards, or earthquakes? You also need to plan for unforeseeable events such as terrorist attack, plane crashes and civil unrest.

Here are ten points to consider.

  1. Disaster planning must limit access to critical users only. You will not have enough channels in extreme situations.
  2. Identify, protect and prioritize critical user groups in advance, and build them into your talkgroup structure.
  3. Define your interoperability needs – who needs to talk to whom?
  4. When will you use encryption? Can you communicate effectively with necessary agencies and groups?
  5. Estimate how long different disaster scenarios might leave you without power. You may have to be independent for 72 hours or more, without power, fuel or support.
  6. Consider investing in transportable systems that can be rapidly deployed.
  7. Prepare and maintain a cache of radios that your mutual aid partners can locate and use.
  8. Keep cached radios programmed, maintained and updated with the rest of your fleet – don’t discover this has not happened under pressure.
  9. Train and practice simulated emergencies at least annually.
  10. Ensure all your procedures are thoroughly documented in electronic and hard copy formats, easy to follow and easy to find by everyone who might need them.

Site equipment

Even with the best planning, you may be without some sites in a disaster. Good planning and design can mitigate the effects of this on your communications.

Remember, a generator can take five to seven minutes to fire up, which may leave workers without communication at a critical time. If the power is out, utilities and propane companies may not have power to pump fuel.

Coverage and capacity

What will happen to your communication if you lose a site? Some systems use geographically-distributed back-up sites. Others over-provision the sites so that no important area of operations is covered by just one site.

While this is highly recommended, it is expensive and creates its own technical challenges, especially in multicast systems, requiring finely-tuning roaming performance of subscriber units.

In every case, you need to limit traffic on your system to those who need to be involved. Emergency plans should include means to cut off “roamers” and anyone who does not need to participate. Allowing people to monitor activities while they are scanning may mean additional groups will load. This may choke your system.

Be prepared to completely isolate a site in emergency, especially on larger multisite systems as it will likely improve remaining capacity.


The only processes that will be effective in an emergency are those that are well known to your users. Expensive patching devices, ISSI (Inter-Sub-System Interfaces) and extra groups or channels will not help unless users understand how to take advantage of them.

Keep processes simple and make sure all your users are well trained. Avoid spending large sums of money on high tech devices – the best solutions may be operational.

Interoperating with other organizations
Planning for critical event interoperability with partners is a daily task, so that you are prepared for rapid deployment. You need to establish common process and technology with those you need to work with in a disaster.

  • Define the complexity of your interoperability needs – who will need to talk to whom.
  • Build critical user groups into your talkgroup structure.
  • Keep procedures as simple as possible as you may not have access to your full system in an emergency.
  • Protect capacity by prioritizing and limiting who will talk, in advance. Allow only critical groups to operate.
  • Identify the need for unencrypted interoperability channels for external agencies.
  • Use transportable systems and portable repeaters if possible.
  • Consider storing the configuration files for radio models used by your interoperability partners so you can interoperate at every level.

A recent addition to the P25 standard is ISSI (Inter Sub-System Interfaces). Implementing ISSI on your system allows you to connect your LMR system to other radio systems. This is invaluable for interoperability, but it does require close cooperation, so that all agencies concerned have the same expectations, processes and configurations.

Procedures and Training

It is very difficult to predict all emergency scenarios and prepare for every eventuality. However, being well prepared for the most obvious or most critical ones may be sufficient. Involving a large, cross-functional team in designing your emergency SOPs and then practicing the various scenarios regularly are important to your overall preparedness.

Training for different scenarios should include procedures for reduced communication capacity.
Your users need to know how to interoperate with others in an event, so you should train with your interoperability partners.

While this clearly includes your mutual aid partners and neighboring agencies, you may need to include transit, schools, municipal teams, Red Cross, National Guard and hospitals. Everyone needs to know how to interoperate before they need it.

Your people need to train with the equipment, so they know what to do in an emergency – including training them to stay off their radios, unless they urgently need to communicate.

A major benefit of training and regular drills is to identify weaknesses in your equipment, procedures or people, which you then have the opportunity to improve. Reviews and debriefs after training, drills and real events are invaluable and can save lives in the future.

While it can be difficult to justify the time and cost of extensive training programs, multi-agency, multi-discipline training has the advantage of shared funding, with each participating agency bringing their own training budget to the event.

  • Factor in the roles of other communication technologies during events.
  • Train everyone with the equipment they will use in an emergency. New or upgraded equipment requires fresh training.
  • Train your radio users to stay off their radios unless they need to communicate, and empower dispatchers to turn off non-priority talk groups during events.
  • Uncontrolled interoperability can consume valuable bandwidth – establish common process and train users in it.

Technical solutions

While your system design should provide a high degree of peace of mind, there are some event-specific approaches you can take to strengthen your communications in the event of a disaster.

COWs (Comms On Wheels)
Extreme weather events can indiscriminately put communication sites or their linking out of action. A COW (Communication on Wheels) trailer or truck with its own repeaters, antenna and linking capability can provide temporary communications in an affected area. Adding a small, rugged Private Broadband LTE system with a form factor can include high speed data.

Offsite control
IP-based console systems can manage your dispatch operation remotely, away from the normal control centers – wherever a network connection is available.

Power at sites
Backing up your power supplies with dual – even triple – redundancy can prevent communications outage, particularly where towers are at elevation, remote or inaccessible during winter.

The greatest barrier to effective response in an emergency is low levels of preparedness – lack of training, and being unfamiliar with emergency SOPs. Technical issues come second.

Chapter 8: The Human Factor has more information on training and procedures. Rather than waiting for that blog post you can skip ahead and simply read that article now by downloading the guide.

10 ways to protect and strengthen your LMR system - Download Guide This article is taken from the 10 part guide to Tougher LMR Systems.

If you would like to download this article and the other articles in the series you can do that on the Tait website.

Additional Articles:

  1. Major Event Preparedness
  2. Natural Disasters Déjà vu
  3. How would your organization cope? Preventing communications chaos in a disaster.

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