What am I actually hearing on this police scanner app?
October 14, 2010 9:19 AM   Subscribe

What am I actually hearing on this police scanner app?

I've been listening to transmissions from my local (Springfield, MO) police department via the 5-0 Radio Police Scanner iPhone app (the free version). Am I actually hearing every single dispatch sent out from the police department, or are there different channels that I'd be able to access with a proper scanner? I ask because sometimes it's strangely silent for long periods of time (sometimes over 5 minutes), and I can't imagine there being nothing talked about during that time.
posted by nitsuj to Law & Government (5 answers total) 5 users marked this as a favorite
Response by poster: I should also note that the "silent" periods do not seem to be because of an app or connection problem, as I never hear a break in the white noise static in the background.
posted by nitsuj at 9:30 AM on October 14, 2010

Most large cities will have multiple radio channels for police to minimize interference, especially when things get busy. Most of the setups I've seen are based on geography or by precinct (if they use such a system). They almost always have secondary tactical channels for use under special circumstances or by groups like SWAT teams. So it may be that there's very little going on or you're just on the wrong channel.

Another possibility is that most of the traffic is data, being sent back and forth from terminals in the police cars. This has eliminated a lot of the voice traffic around me, for sure.
posted by tommasz at 9:30 AM on October 14, 2010

Most of them using trunking to separate traffic to district/quadrant/whatever and will also have options for different groups and for more official/unofficial comms.
posted by proj at 9:46 AM on October 14, 2010

Best answer: You should compare what you are hearing on the iPhone app to what is being broadcast on the Radio Reference feed. Typically, the police scanner apps on the iPhone are just relaying the feeds that are found at Radio Reference. If you are hearing the same communication, then your hunch is (partially) correct: you're not hearing everything that you could potentially hear.

According to the details on that page, the feed is broadcasting about 14 "talk groups". Some radio systems operate in a way that multiple communications can happen on the same frequencies through a process called "trunking". It's a way to cut down on the number of frequencies that are needed, since not all of the communications will be used at the same time.

Looking at the detail page for Green County Public Safety, there are way more talk groups available. The majority of these are little used or of little interest, but they are out there.

As far as police, you are (most likely) hearing every transmission that is being broadcast but there really isn't that much being broadcast. Even if there seems to be a lot of activity in the area, radio communication doesn't always have to very active. A lot of agencies will dispatch the initial call but send the majority of the details through a data terminal. Officers can also run their own license and plate checks from their car, usually, further cutting down on the communications. If one officer needs to talk to another, it's mot likely on a cell phone and not on the radio (like it used to be).

tl;dr answer: You are probably hearing everything that is going on with the police department. But if you had a scanner, you could hear other police departments and agencies.
posted by tommccabe at 9:55 AM on October 14, 2010 [1 favorite]

There isn't much that a police radio is actually used for. Check ins, running names/ license plates, occasional announcements. There is (shouldn't be) no chitter chatter, as the radio is recorded and available to be used as evidence if there is any wrongdoing going on.

They use their cell phones to get around that now.
posted by gjc at 4:33 PM on October 14, 2010

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