Noah517:
Thank you for the information. The code works perfectly. I have my ham radio license so I am going to output the audio to a handheld vhf radio and transmit my license with the data.
Here in the UK you cannot use your amateur licence for airborne transmitters, so we are restricted to using ISM band devices, typically at 10mW only.
Simple radio modules such as the RFM22\SI4432 or indeed the LoRa devices can produce FSK RTTY, this is much more effective than AFSK RTTY, distance wise. Baud rate is low, typically 100 - 200baud, but that is OK.
The FSK RTTY can cover similar distances too, no need to send a UHF handheld up in a balloon and use large amounts of transmit power to compensate.