An automatic packet reporting system is a system used for real-time digital communications, employed amateur HAM radio in particular. However, this is used in a very different way as compared with your typical amateur music station! Likewise, it’s not something you’ll be able to listen in on using a police scanner.
That’s because APRS is essentially a protocol for compressing information, providing a standardized and convenient way to share information over a wide area that goes beyond the spoken word. Data transmitted using this system can include GPS (global positioning system) coordinates, weather station telemetry, text messages, announcements, and more; and therefore might be useful for weather radio or numerous other applications.
How it Works
APRS data is usually transmitted over a single shared frequency (which varies depending on country) and is intended to be repeated locally by relay stations – thereby allowing for widespread broadcasting. Repeaters work by intercepting messages and then replicating the same signal to send out again – thereby strengthening the signal and helping it to travel further. These digipeaters also helps to keep track of those packets in order to avoid sending the same packet multiple times for instance.
This allows for data and information to be sent without establishing a connection to a particular station – it can be broadcast generally to a wide area.
One of the most common uses of APRS is the position/object/item packet. These provide the longitude and latitude of an item that can be sent out automatically.
So why might this be useful? Well, one good example would be for Skywarn.
Skywarn is an initiative that utilizes a network of ham radio operators – often mobile ham radio – that can browse the airwaves in search of information about storms, and then report back to the organizing body (the NWS). To help them with this endeavor, automatic weather stations will provide spotter positions and weather observations via automatic packet reporting systems, so that those spotters can quickly get information about precise location of a report and use that to further their investigations.
As you can see then, APRS is a useful protocol that has numerous applications – allowing information other than purely analog voice to be sent and received in an automated fashion.
What is a Packet?
To help elaborate just a little further, keep in mind that a ‘packet’ is any small piece of information. Seeing as any form of communication will have a limit in terms of how much information can be sent in one go (described by the bandwidth – which is why whole movies don’t download in an instant), it is important for that information to be broken down into smaller pieces. These are called packets.
Packets are perfect for communicating over long distances, and are ideal when combined with shortwave radio.
In fact, what many people don’t realize is that this works in just the same way as many other forms of wireless communication: including WiFi, cellular data, and even Bluetooth. All of it requires packets of data, sent by radio waves!