1. For an experimental works, we have been evaluating FT8 with superb results.
2. However, we want to evaluate a FASTER mode. 3. Any recommendation? Is JT9E a good choice, at 5 seconds cycle time, instead of 15 seconds FT8? Does JT9E mode use the same 'advanced decode technologies' as FT8? How about MSK144? Seems it uses a much wider bandwidth, to send 18 character free text in 5 seconds. Seem not very efficient. 4. After reading highly informative articles of https://physics.princeton.edu/pulsar/k1jt/Work_the_World_part2.pdf https://physics.princeton.edu/pulsar/k1jt/Work_the_World_part1.pdf 5. Wold appreciate clarification of a few questions a. What is the decode sensitivity of JT9E, compare with -20dB SNR of FT8? b. It supports, same as FT8, 13 characters free text, same 42 characters set, right? c. How is the 'FEC strength'? Specifically, time diversity. Does it spreads the 'data' throughout the transmission time, so that, signal with burst noise of, says, 0.4 seconds, will be decoded successfully. d. Bandwidth is 225 Hz, right? e. WSJT-X version 2.0 will decode all signal within the 5 kHz maximum bandwidth, and output via UDP port as "decode message type", right? Same as FT8. f. What are the formula for 9 symbol tone frequency spacing, for encoding by DDS chip? Symbol 0 is 700Hz Symbol 1 is 700 + (1 X ??? Hz) Symbol 2 is 700 + (2 X ??? Hz) g. TX and RX AF carrier freq can be freely set to any freq within the 0 to 5 kHz, same as FT8, right? h. Does WSJT-X version 2, FT8 and JT9E mode, perform the below functions now. The older article said it did NOT do that in Oct 2017. Quoted from article, "For JT65 and WSPR the present decoders go one step further, taking advantage of the fact that when a signal with strong EEC has been decoded we know its transmitted waveform exactly. An amplitude-scaled version of that waveform can be subtracted from the received data and the decoder executed on the remainder to decode weaker, previously hidden signals. This approach has proved very effective: it frequently decodes weak signals lying within 1 or 2Hz of much stronger ones. " >From on air traffic, WSJT-X ver 2.0, FT8 mode can decode a message at says 700Hz. Then, a bit later, it ALSO decode another message at 710Hz which is 10Hz away, instead of the needed 60Hz away. Does it perform the work via the above mechanism? 73 Simon _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
