PulseModem A is an APRS client, that reads and reports APRS location and message. The messages are relayed to the APRS-IS network.
APRS is a digital communications protocol that can exchanges information among large number of stations both local and global.
You can send directly via Internet, a.k.a. "TCP/IP" or by radio frequency.
You just need to connect your Amateur Radio with your iPhone with an audio cable. A built-in modem will convert your payload message to AX.25 encoded AFSK message, which will then be sent via your radio.
You just need to setup your Callsign SSID and APRS passcode, then you are connected to the APRS-IS feed. All station messages within 100km of your current position will be read.
A built-in AX.25 modem can also decode RF signal received from your radio. So you do not need Internet in this case!
It depends your area. Common frequnecy in North America is 144.390MHz whereas it is 144.640MHz in other areas.
You can scan 144.390 to 145.570MHz for APRS signal. It is a very identicable chirp which is less than 2 seconds in length.
PulseModem uses the built-in GPS information provided by your iPhone and iPad.
Future versions may interface other standalone GPS units via BLE.
PulseModem A is open source iOS app. In the spirit of amateur radio, the app has to be open sourced. It also leverages many open source technologies, too.
Please go to www.pulsemodem.com for more info.