gr-APRS - A GNU Radio Block for Receiving APRS

GNU Radio Hierarchial Block(s) to Test and Receive APRS Packet (with examples). Tested on GNU Radio v3.7.10 / Linux Ubuntu.

Dependency

Installations

This OOT Module is built upon GNU Radio hierarchial block scheme. The hierarchial block itself is “transparently” built graphically / visually using GRC. The hier blocks are provided in the gr-APRS/HierBlock folder. Installation steps :

And then very important steps :

Finish, and now you can open grc files on gr-APRS/Examples/ or gr-APRS/TestScripts/ and run it.

About The HDLC to AX.25 block

This block which functions to convert HDLC data into TNC2 APRS formats is constructed from the “Python Block” which native to the GNU Radio Companion. To build one yourself:

Hier Blocks

All the hier blocks are constructed graphically using GNU Radio Companion. AFSK Demod hier block is required by the APRS Rx hier block (hier block which contains another hier block within), so it should be installed first.

AFSK Demod

APRS Rx

Examples

There are some grc examples included in gr-APRS/Examples and gr-APRS/TestScripts folder. WAV files are also included in the gr-APRS/WAV for testing purposes.

A Few notes:

APRS RX RTL

From gr-APRS/Examples/APRS_RX_RTL.grc. This examples utilizes the low cost RTL SDR dongle for receiving APRS signal on 144.390 Mhz (for usage on another frequency, please change the frequency in the grc).

APRS SCARD

From gr-APRS/Examples/APRS_SCARD.grc. This examples utilizes the onboard sound card for the usage with a VHF Radio receiver. Audio from the Radio SPK output should be fed into the MIC input of your soundcard.

APRS AFSK Complete WAV

From gr-APRS/TestScripts/APRS_AFSK_Complete_WAV.grc. This examples will decode AFSK audio files which included in gr-APRS/WAV. This example is mainly for testing purposes (for example, to find the best values of Mu and Gain Mu).

TODO

Acknwoledgement

Contributing

  1. Fork it https://github.com/handiko/gr-APRS/fork
  2. Create new branch (git checkout -b add-blah-blah)
  3. Do some editing / create new feature
  4. Commit your works (git commit -m "Adding some blah blah blah..")
  5. Push to the branch (git push -u origin add-blah-blah)
  6. Create a new Pull Request