How can I get file transfer rates above 566bps in VARA FM Chat? S/N between stations is +22.4 / +22.3 and VU is -21 / -25 so signal is solid. Tried sending several file types and transfer rate never goes above 566bps. Both versions of VARA are registered. Running VARA Chat as VARA FM. Both radios are using VARA wide into 9800bps 6 pin data ports and Signalink Black audio transformers with pin 4 connected (9600) instead of 1200bps pin 5.