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PSK31 is a digital communications mode which is intended for live keyboard-to-keyboard conversations, similar to radioteletype. Its data rate is 31.25 bauds (about 50 word-per-minute), and its narrow bandwidth (approximately 60 Hz at -26 dB) reduces its susceptibility to noise. PSK31's ITU emission designator is 60H0J2B. It uses BPSK modulation without error correction or QPSK modulation with error correction (convolutional encoding and Viterbi decoding). In order to eliminate splatter from the phase-reversals inherent to PSK, the output is cosine-filtered before reaching the transmitter audio input. PSK31 is readily monitored and the most popular implementation uses DSP software running on a computer soundcard inside an IBM PC-compatible computer.
There is a preamble at the start of each transmission and a postamble at the end. The preamble is an idle signal of continuous zeroes, corresponding to continuous phase reversals at the symbol rate of 31.25 reversals/second. The postamble is just continuous unmodulated carrier, representing a series of logical ones. This makes it possible to use the presence or absence of the reversals to squelch the decoder so that the screen doesnt fill with noise when there is no signal.
Originally posted by Skada
Most satellite Internets still need a phone cord connection to send out data. So, you would still need to be connected in to the infrastructure. Almost there, but I think shortwave PC might be the way to go.