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What's WSJT

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 ratePitch intervalBandwidthTx/Rx timeSNR       Sub mode
ApplicationWSJT
WSJT-X
JTMS
     MSK1378 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-FSK21.5 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
ApplicationWSJT
WSJT-X
JT4
4-FSK4.375 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

 √   √
QRA6464-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 baud6.25 HZ  50 HZ15 S-21 dB
DXpedition

HF low power

communication


    √


Test Mode:

For testing signal propagation range or strength.

Common test modes of WSJT include WSPR, Echo, etc.

WSPR: Low power transmission is used to detect potential propagation paths.

Echo is to measure your own EME reflected signal. EME signals take about 2.5 seconds to get to and from the moon.

1. Transmit single audio signal for 2.3 seconds;

2. Waiting for 0.2 seconds;

3. Receive 2.3 seconds;

4. Analysis of the signal;

5. Repeat.






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