While portable radios are great for communications, I’ve had times in noisy environments where I couldn’t understand the message. Other weaknesses include the fact that they require batteries, their size, that as electronics they are susceptible to EMP [1], falls, and weather. Finally, they do not allow for directional finding of the other party. As such, I suggest also equipping every member of your team with a small Bosun’s whistle. These small multi-note whistles create a high pitch which can be heard above the din of a crowd. Being multi-note in capability, information can be sent (e.g. high-low for where are you/I’m over here, high-high-high for emergency etc). They are small enough to fit it your pocket, are indestructible and have some direction finding ability to them.
My family has a ‘family whistle’ we’ve used for four generations for finding each-other without having to shout but while my kids can hear me whistle to them, they can’t respond at their age. They can however operate a Bosun’s whistle.
I can think of several scenarios where such whistles could be of use. Can you imagine being separated from your wife and kids in a crowded FEMA [2] camp? Some children remained separated from parents for months after entering the Superdome following Hurricane Katrina. While I have no intention of taking my family into one of those death traps or anywhere else that the “we’re from the government and we’re here to help” folks suggest, Schumer [3] happens. If you and your family find yourselves caught in the wrong place at the wrong time and somehow separated, a kid turns a wrong corner in an airport, or you just want to call them in from the yard for dinner and don’t want to scream, get a Bosun’s whistle. – SF in Hawaii