How it Works: Location, Location, Location

July 9th, 2010

 

This is the first installment of an irregular series we’re calling. “How it Works.” These articles are for the technical minded among you, who want to know a bit more about the inner workings of the HomePatrol-1.

As we mentioned in first two blog posts, HomePatrol-1 uses radio information provided by www.RadioReference.com, combined with our unique channel selection methods to bring you your local radio traffic. So, how does all this work?

A couple of years ago, the administrators at RadioReference embarked on an ambitious mission to assign specific location information (or a “geotag”) to all radio systems in the RadioReference database. No small feat, as that database includes thousands of systems which incorporate tens of thousands of “geotaggable” elements. This effort is ongoing, and the location information gets better every day. With the release of HomePatrol-1, we expect this geotagging process to advance by leaps and bounds.

A geotag consists of a latitude, a longitude, and a range. This tag describes a circle centered at the latitude/longitude that fully encompasses the political entity (i.e. city, town, state, etc.) served by the radio system. Taking a look at a some of the systems in the Fort Worth, TX area, you can see that each of the systems has its own little circle. These roughly outline each system’s intended coverage.

If you were to look in RadioReference.com, you’d see that each of these circles also includes all the radio system information (frequencies, descriptions, tags indicating how each channel is used, etc).

Now, lets look at what the HomePatrol-1 does when you give it your location. If you use your Zip Code, HomePatrol-1 sets your location as being somewhere within 10 miles of the center of that zip code. Not very precise, but good enough for catching local comms. We’ve drawn that circle in blue on the map, below.

HomePatrol-1 will select channels from all of the systems (red circles) that overlap the blue circle (your approximate location). So, that system down south that covers Burleson will be included even though only a portion of it is covered, but little Haslet, way up north, will not be included.

Each method for selecting your location uses a different sized circle. In addition to the 10-mile Zip Code radius, HomePatrol-1 will use:

  • 20-miles radius from the center of a city when using city selection
  • 30-miles radius from the location of the discovered radio tower when using Auto Locate
  • 0-miles radius if you connect a GPS or manually enter your latitude or longitude.

Hold on, 0 miles? Well what that means is that your location is precisely known. So in order for a radio system to be selected, its little red circle would have to enclose your precise position. This setting is great if you are traveling…HomePatrol-1 will automatically select and deselect systems as you drive through each system’s coverage zone.

Want to hear more (or less) than what the Home-Patrol-1 selected? You can manually change the range setting to be bigger (to include more systems) or smaller (to include fewer systems) by tapping RANGE on the main screen and adjusting the range up or down. Just keep in mind that if you are not using GPS, the range will be from the center of the zip code, city or radio tower location…not your precise location.

Want to know more about how something works? Head on over to our Forums section and ask away, and watch for detailed answers in a future “How it Works” column.

 

 
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