Tracer2

Tracer2 is a mobile app that performs an APRS TRACKER using a radio transmitter (or an internet connection without transmitter when used in “direct mode”).

It is a software, for HAM radio amateurs, that may be used for tracking vehicles without a dedicated equipment and without a gsm or internet connection (when not used in direct internet mode).

The app uses the GPS receiver of the phone to determinate the position and the movements of the vehicle an produces the Aprs Packets sound that can be broadcasted by a HAM radio transmitter (in vhf or in other band). The transmitted information is then received and forwarded, by the Gate stations, to the APRS network so that the vehicle can be seen in maps of aprs-clients or on particular websites, for example aprs.fi or aprsdirect.com.

If you already own an unused cellular phone, Tracer2 represents a very cheap, compact and easy-to-use solution for implementing a temporary or permanent radio amateur tracking system.

In the main page of the app there are two indicator lights: one indicates the presence of a good GPS signal and one indicates whether the vehicle is moving (green) or is considered stationary (orange). Near these two indicators there is the indication of the wind rose direction towards which the vehicle moves. When used in direct internet mode there is a third light indicator that monitors the internet connection. There are also two counters reporting the number of transmitted packets and the number of packets that will be transmitted in the next time slot, according to the aprs channel accessing rules. When you leave the main page while the Tracer is running, the app service will continue working in the background, you can recall the main page by tapping the service icon in the android status bar. When the main page is visualized, it shows, in the events hub, the information about movements and stops, but it doesn’t report events generated when the page is closed.

For a continuous use of the tracker it is recommended to use a phone charger or a power bank. You will also need a cable to connect the phone audio output to the mic input of a ham radio transmitter. You will find a simple implementation of this audio cable in the app site. The transmitter’s vox function may be used to switch the ptt button, if the vox needs more time to be activated you can extend the packet preamble in the app settings. For a correct operation, set the phone's multimedia audio volume level not too loud to avoid over-modulation.

The app works with high accuracy location data, so it needs, in same situations, more than a few minutes to fix the position and start tracing (indoor use is not recommended). The positions transmitted in the aprs packets are not fixed on time interval base (as in other trackers), they are fixed according to a smart position algorithm that reveals the meaningful points of the vehicle trace (turns, stops, additional checkpoints, etc.).

On the app's settings page it is possible to define the "privacy zones" within which the vehicle's position will not be transmitted.

App permissions:

This app uses Location permission to get the actual position that is transmitted in the aprs location messages.

Other related Apps:

• IGate2 : an APRS IGate for Android using a radio receiver or an SDR dongle.

Notice:

• This app is free trial of the Tracer2 Pro app. It has a limit of 50 forwarded packets per session. If you like this app, buy the full-feature version (Tracer2 Pro) in the Google Play Store. It is cheap!

• This app has been tested in devices running Android 5 and up. If you find any error on your special device, please, do not give a negative feedback but feel free to mail the problem to the author and he will fix it.