What's WSJT

WSJT is Weak Signal Joe Taylor, and a computer program. The program of WSJT was initially written by Joe Taylor, used for weak-signal radio communication between amateur radio operators. Now there is a new version called WSJT-X for multipurpose, and WSJT is main used for DX above VHF. There are many working modes for WSJT and WSJT-X. They can be divided into fast mode, slow mode and test mode.

Fast Mode:

In the mode, communication is usually established under unstable communication conditions, such as meteor scattering, ionospheric scattering, and so on. with strong error correction rate, suitable for DX above VHF.

Common fast modes of WSJT include JTMS, FSK441, ISCAR, JT6M, MSK144, etc.

Mode Name	Modulation mode	Baud rate	Pitch interval	Bandwidth	Tx/Rx time	SNR	Sub mode	Application	WSJT	WSJT-X
JTMS	MSK	1378 baud	689 HZ	2067HZ	30 S	-1 dB	\	meteor scattering	√
FSK441	4-FSK	441 baud	441 HZ	1764HZ	30 S	-1 dB	FSK315, or North America, 315 baud, different tones	meteor scattering	√
MSK144	OQPSK	2000 baud	441 HZ	2400HZ	30 S	-8 dB	Sh(short message mode)	meteor scattering		√
ISCAR	42-FSK	21.5/43.1 baud	21.5/43.1 HZ	2067HZ	30 S	-17 dB	A/B (B is twice as wide and twice as fast as A)	Ionospheric scattering	√	√
JT6M	44-FSK	21.5 baud	21.5HZ	947HZ	30 S	-10 dB	\	Ionospheric scattering	√

Slow Mode:

In the mode, establish long-term low-power communication under stable communication conditions, suitable for HF DX and EME.

Common slow modes of WSJT include JT65, QRA64, JT4, JT9, FT8, etc.

Mode Name	Modulation mode	Baud rate	Pitch interval	Bandwidth	Tx/Rx time	SNR	Sub mode	Application	WSJT	WSJT-X
JT4	4-FSK	4.375 baud	4.375~ 315 HZ	17.5~ 1260 HZ	60 S	-23 ~-17 dB	A~G (A has the smallest tonal interval, the most sensitive, and G has the largest. Longjiang-2 microsatellites from china is using JT4G)	Microwave EME	√	√
QRA64	64-FSK	1.736~ 27.778 baud	1.736~ 27.778 HZ	111.1~ 1751.7 HZ	60 S	-26 ~-22 dB	A~E (A has the smallest tonal interval, the most sensitive, and E has the largest)	VHF/UHF, EME		√
JT65	65-FSK	2.69 baud	2.69/5.38 /10.77 HZ	178/355 /711 HZ	60/ 30 S	-25~ -21 dB	A/B/C/B2/C2 (A has the smallest tonal interval, the most sensitive, B2: time is short)	VHF/UHF, EME(B/C) MF/HF low power communication(A)	√	A/B/C
JT9	9-FSK	1.736~ 222.222 baud	1.736~ 222.222 HZ	15.6~ 1779.5 HZ	60 S	-27 ~-20 dB	A~H (A has the smallest tonal interval, the most sensitive, and H has the largest)	LF/MF/HF low power communication		√
FT8	8-FSK	6.25 baud	6.25 HZ	50 HZ	15 S	-21 dB	DXpedition	HF low power communication		√