have made quite a few changes!
1) Stripped out the Interrupt based RTTY (while technologically superior just doesn't sit with my style of coding)
2) replaced the loop() quite a bit - quite simple pattern that is run through, does a few checks:
2a) resets everything every 100 strings
2b) every 5 strings if the GPS is ON will check the navmode and correct it
2c) every 2 minutes (millis counter) it will prep a APRS packet, first working out its position, then adding the correct call suffix then sending it via the HX-1
2d) finally it'll transmit a RTTY string via the RFM22b