New Digital Mode from K1JT

“Dear WSJT-X Beta-Test Colleagues,

Steve (K9AN) and I have developed a potential new mode for WSJT-X. We’re
calling the mode “FT8” (Franke-Taylor design, 8-FSK modulation).

FT8 is designed for situations like multi-hop Es where signals may be
weak and fading, openings may be short, and you want fast completion of
reliable, confirmable QSOs.

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, keying rate = tone spacing = 5.86 Hz
– Waveform: Continuous phase, constant envelope
– Occupied bandwidth: 47 Hz
– Synchronization: three 7×7 Costas arrays (start, middle, end of Tx)
– Transmission duration: 79*2048/12000 = 13.48 s
– 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 after manual start of QSO

*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.

Three extra bits are available in the message payload, with uses yet to
be defined. We have in mind special message formats that might be used
in contests, and the like. Your considered suggestions for use of these
bits are very welcome!

K1JT, K9AN, and G4WJS have conducted on-the-air tests of FT8 with
excellent results. We’re now at a stage where tests under a wider range
of conditions are desirable. If you can build WSJT-X from source code
revision r7750 or later, and would like to help, please do so and report
your results to us! Pre-built installation packages will be made
available after further testing is completed.

Suggestions for FT8 setup and examples of use can be found in a screen
shot posted here: http://physics.princeton.edu/pulsar/k1jt/ft8.png

We look forward to receiving your feedback.

— 73, Joe, K1JT “

Hi all,

It will help to have some initial frequency coordination among those
testing the new FT8 mode in WSJT-X v1.7.1.

To help get things started, we suggest using the following frequencies:

Band MHz
————-
160 1.841
80 3.579
40 7.079
30 10.141
20 14.079
17 18.105
15 21.079
12 24.920
10 28.079
6 50.313
4 70.094
————-

Most of these suggestions follow a simple guideline: add 3 kHz to the
commonly used JT65 dial frequency.

For 6 meters we suggest using 50.313, which should be consistent with
band plans in all IARU Regions. (Six meter activity that’s now on
50.276, world-wide, might be moved to 50.310.)

We are very much open to suggestions for changes in the above table.

— 73, Joe, K1JT”

Source: Yahoo Group

DOWNLOAD WSJT-X FOR FT8 HERE

Equipment

DX Engineering UT-KIT4 Complete Coax Cable Tool Kits DXE-UT-KIT4

January 05, 2016 in: Equipment No comments

DX Engineering DXE-UT-KIT4 Complete Coax Cable Tool Kits are cost-saving tool kits contained in a handsome, convenient carrying case. They are designed to enable fast, easy installation of PL-259 and Type N connectors. These kits are furnis... Read more

RS-918SSB HF SDR Transceiver

April 07, 2017 No comments
AOR AR8200 -MK3 ( 500KHz to 3GHz )

December 30, 2014 No comments
GroundBreaker – Isolate your audio to remove RFI and ground loop problems!

June 27, 2018 No comments
ColibriNANO USB SDR Receiver

March 19, 2017 No comments

VHF

Getting started on Ham Radio 2M FM BY K7AGE

July 17, 2015 in: VHF No comments

In this series of Ham Radio videos, I’ll show you how to program a 2M HT to get on the air along with some of the basics of 2M FM operating.. In Part 1, I describes the Icom IC-V80 Sport radio and some of the basics of operating dista... Read more