Hi David,
There are lots of factors for sure including the robustness of the mode, noise floor of the frequency, width of the passband, the regional legality of symbols/sec of the transmitter, etc. it goes on and on.
Thanks for the reminder! I'll check my local coordinator's band plan to see which channels are for digital simplex.
Personally, I personally wouldn't bother with RTTY as it's not 8bit clean (if you need to send binary data), it's not very robust, it's quite slow (especially for a medium like FM over VHF), etc.
I'm stuck at physical layer i.e. didn't manage to convert any byte into audio, that's why I wanted to start with RTTY. With minimodem I could run echo "hello, world" | minimodem -t rtty and it plays the tones. If I want to play any sound with Direwolf other than direwolf -x, do I must set up a network stack and run echo "hello, world" | nc localhost 8000?
Is your goal to send arbitrary strings?
Yes for today. Once I can send arbitrary bytes on air, the L2~L7 are just computer science, which I have slightly more confidence with.
Thanks,
Yishuai
