Bat-radia

f there is one thing that is often missing from the commonly shown contents of Batman's utility belt:

A simple police scanner!

Now I suppose in the high-techie sort of portrail of Batman there is probably a nano-scanner or some such thing built in his mantel. And of course, he is often shown with a high-tech communications system for communicating with his allies.

But a low scale, independent Batman doesn't need those things. What he needs is a handheld scanner radio. In fact, there's a pretty good argument why Batman would go low-tech for this kind of thing: If it's just a reciever and not an emitter no one should be able to track him. Scanners are completely passive.

So what is a scanner radio? A scanner is a radio receiver that scans multiple frequencies looking for transmitions.

The idea is simple but some of the details can get confusing unless they are explained chronologically rather than as they come up. Back in the 1930s people like the police would broadcast through AM radio stations so that anyone with a radio could hear. In order to have their own channel, they would change to a less public frequency. Of course, then and now anybody could just follow them and keep listening as long as they could tune into that channel. Each channel required a specific quartz-crystal which so that your radio could tune in. So the crystal almost acted like a key.