FT8/FT4/FST4WJT9: WSJT 2-Way Narrow Modes For Amateur Radio
The mode is described by K1JT as follows:
Important characteristics
- T/R sequence length: 15 s
- Message length: 77 bits (up from 75 in prior versions) + 12-bit CRC
- FEC code: LDPC(174,87)
- Modulation: 8-FSK, keying rate = tone spacing = 5.86 Hz
- Waveform: Continuous phase, constant envelope
- Occupied bandwidth: 47 Hz (later refined to 50 Hz)
- Synchronization
- Transmission duration: 79*2048/12000 = 13.48 s (note some refinements have been made since the original description and the duration is now 12.64 seconds)
- Decoding threshold: -20 dB (perhaps -24 dB with AP decoding, TBD)
- Operational behavior: similar to HF usage of JT9, JT65
- Multi-decoder: finds and decodes all FT8 signals in passband
- Auto-sequencing
*Comparison with slow modes JT9, JT65, QRA64:* FT8 is a few dB less sensitive but allows completion of QSOs four times faster. Bandwidth is greater than JT9, but about 1/4 of JT65A and less than 1/2 QRA64.
*Comparison with fast modes JT9E-H:* FT8 is significantly more sensitive, has much smaller bandwidth, uses the vertical waterfall, and offers multi-decoding over the full displayed passband.
*Still to come, not yet implemented:* We plan to implement signal subtraction, two-pass decoding, and use of "a priori" (already known) information as it accumulates during a QSO. (note that since the original release, a significant portion of this has since been implemented)
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In addition, a new mode “FT4” is in development. More details on this can be found in the announcements section
Avisos
New one here in my shack. Only thing running is WSJT-X connected to my FT2000. I am just letting it listen, in fact here I let it run over night. No other rigs transmitting. WSJT-X is still decoding normally… Mais but has lost rig control. It does this randomly, and frequently. Only way to recover is to reboot the computer, nothing else will recover it. Don't have to reboot the rig, just the computer. WSJT-X V2.2.2. Any ideas? K0YA
Rex Weatherford compartilhou um link.
KE0MHJ/R Jan VHF Contest Limited Rover
6m, 2m, 70cm
Follow me on APRS at KE0MHJ-5
Saturday EM39, EM38, EM28, EM29, EN20, EN30.
Check QRZ.com for a few details.
Thanks for the contacts, lets hope for an opening in EN20.
Robert Grant compartilhou uma publicação.
Osvaldo Araujo compartilhou um link.
Once again it is time to remind members of one of our rules, it's that we ask members not to ADD or INVITE others. We have had complaints, and have been reported to Facebook, by people who have been added and wonder why they are getting a notice from the group. They think its SPAM or SPOOF, and this creates issues.
If you'd like to add or… Mais invite people, tell them about the group, and let them make their own decisions. They will need to answer the mandatory group questions just like everyone else, but they'll be doing it voluntarily.
Please follow this rule, we don't need the 'added' headaches.
Pun intended.
James Shaver alterou o nome do grupo "FT8/FT4/JT9: WSJT 2-Way Narrow Modes For Amateur Radio" para "FT8/FT4/FST4WJT9: WSJT 2-Way Narrow Modes For Amateur Radio".
Fred Price compartilhou um link.
This is a reminder for those who are going to participate in the ARRL January VHF contest this weekend.
Make sure you are using the NA VHF Contest mode. To set this up
File>Settings>Advanced tab put a check in… Mais Special operating activity and then check NA VHF Contest, then click ok. The report is grid square and not a SNR. This is no matter if using FT8, FT4, or MSK144.
Information about the contest can be found here

















