AX.25 for APRS with FSK Modulation

[kml183]

Hi there!

I am working on some code for a little packet modem that you can interface with over UART/I2C that will support the AX.25 specification. I am using a FSK modulator over RF for my physical layer (si466x G(FSK) chip).

Is it likely that my transmissions would be picked up by a station that relays information to a site like https://aprs.fi? What baud rates are reasonable for APRS?

[ftg]

For 2m amateur band it is 1200baud Bell 202 and essentially nothing else when it comes to pure packet APRS.

Many DMR radios can also send their position along the network, but that is a pure data packet over DMR, even if it eventually shows up on APRS.fi.
There is also 70cm LoRa APRS that uses LoRa for sending the APRS packets.

But +90% of all APRS traffic is 1200baud Bell 202 AFSK.

[NivagSwerdna]

Listen on 144.8000 and see if you can hear traffic.   You could start with decoding... that would prove most of your implementation including checksums etc.

Have fun!  This project is a bit of a rite of passage... go for it!

[nixfu]

>  144.8000

Its 144. 390 in North America.