Hallo,
in der neuen Betriebsart lassen sich fast richtige QSOs fahren und das in einem Affentempo. Und auf dem Band ist die Hoelle los.
Bitte von der WSJT-X Seite die Betaversion 1.8 herunter laden.
Auszug: https://physics.princeton.edu/…t/Release_Notes_1.8.0.txt
ZitatAlles anzeigenBrief Description of the FT8 Protocol
-------------------------------------
WSJT-X Version 1.8.0 includes a new mode called FT8, developed by K9AN
and K1JT. The mode name "FT8" stands for "Franke and Taylor, 8-FSK
modulation". FT8 uses 15-second T/R sequences, provides 50% or
better decoding probability down to -20 dB on an AWGN channel, and
maintains good performance on Doppler-spread fading channels. An
auto-sequencing facility includes an option to respond automatically
to the first decoded reply to your CQ. FT8 QSOs are 4 times faster
than those made with JT65 or JT9. FT8 is an excellent mode for HF
DXing and for situations like multi-hop E_s on 6 meters, where deep
QSB may make fast and reliable completion of QSOs desirable.
Some important characteristics of FT8:
- T/R sequence length: 15 s
- Message length: 75 bits + 12-bit CRC
- FEC code: LDPC(174,87)
- Modulation: 8-FSK, tone spacing 6.25 Hz
- Constant-envelope waveform
- Occupied bandwidth: 50 Hz
- Synchronization: 7x7 Costas arrays at start, middle, and end
- Transmission duration: 79*1920/12000 = 12.64 s
- Decoding threshold: -20 dB; several dB lower with AP decoding
- Multi-decoder finds and decodes all FT8 signals in passband
- Optional auto-sequencing and auto-reply to a CQ response
- Operational behavior similar to JT9, JT65
73 de Hajo