[aprssig] PSK31 and OLPC?

[Jim Lux]

While the idea of a little HF modem that hooks up to the OLPC is interesting, I don't know that PSK31 is an appropriate modulation format.  Recall that PSK31 was designed with different design constraints than the sort of wide area tactical comms that Bob is talking about.  It had to run on a limited horsepower PC (substantially less than the OLPC has), be suitable for ham-to-ham keyboard interaction (not message passing), and, not least, had to be something that the originator felt comfortable implementing.

Just because it is popular with hams does not mean that it is a good choice for non-ham HF comms.

For message passing, I think there are better choices. One might want to have some form of FEC, for instance.  With the processing available in the PC, one can probably use more sophisticated signal processing.   Why not use something like MIL-STD-188 ALE?

Jim, W6RMK