JT65

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JT65
JT65AWaterfall.png
Frequencies 1838.0 kHzKiloHertz (kHz) 10^3 Hz1,838,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
1.838 MHzMegaHertz (MHz) 10^6 Hz
,3576.0 kHzKiloHertz (kHz) 10^3 Hz3,576,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
3.576 MHzMegaHertz (MHz) 10^6 Hz
,7039.0 kHzKiloHertz (kHz) 10^3 Hz7,039,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
7.039 MHzMegaHertz (MHz) 10^6 Hz
,7076.0 kHzKiloHertz (kHz) 10^3 Hz7,076,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
7.076 MHzMegaHertz (MHz) 10^6 Hz
,10139.0 kHzKiloHertz (kHz) 10^3 Hz10,139,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
10.139 MHzMegaHertz (MHz) 10^6 Hz
,14076.0 kHzKiloHertz (kHz) 10^3 Hz14,076,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
14.076 MHzMegaHertz (MHz) 10^6 Hz
,18102.0 kHzKiloHertz (kHz) 10^3 Hz18,102,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
18.102 MHzMegaHertz (MHz) 10^6 Hz
,18098.0 kHzKiloHertz (kHz) 10^3 Hz18,098,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
18.098 MHzMegaHertz (MHz) 10^6 Hz
,24917.0 kHzKiloHertz (kHz) 10^3 Hz24,917,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
24.917 MHzMegaHertz (MHz) 10^6 Hz
,50276 kHzKiloHertz (kHz) 10^3 Hz50,276,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
50.276 MHzMegaHertz (MHz) 10^6 Hz
1,838 kHzKiloHertz (kHz) 10^3 Hz
1.838 MHzMegaHertz (MHz) 10^6 Hz
50,276 kHzKiloHertz (kHz) 10^3 Hz
50.276 MHzMegaHertz (MHz) 10^6 Hz
Frequency Range 1.838 MHzMegaHertz (MHz) 10^6 Hz1,838,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
1,838 kHzKiloHertz (kHz) 10^3 Hz
- 50.276 MHzMegaHertz (MHz) 10^6 Hz50,276,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
50,276 kHzKiloHertz (kHz) 10^3 Hz
Mode USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
Modulation MFSKMultiple Frequency Shift-Keying
ACF
Bandwidth 180 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).0.18 kHzKiloHertz (kHz) 10^3 Hz
1.8e-4 MHzMegaHertz (MHz) 10^6 Hz
,360 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).0.36 kHzKiloHertz (kHz) 10^3 Hz
3.6e-4 MHzMegaHertz (MHz) 10^6 Hz
,710 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).0.71 kHzKiloHertz (kHz) 10^3 Hz
7.1e-4 MHzMegaHertz (MHz) 10^6 Hz
0.18 kHzKiloHertz (kHz) 10^3 Hz
1.8e-4 MHzMegaHertz (MHz) 10^6 Hz
0.71 kHzKiloHertz (kHz) 10^3 Hz
7.1e-4 MHzMegaHertz (MHz) 10^6 Hz
Location Worldwide
Short Description JT65 is an amateur radio QSO communication protocol developed by Joe Taylor, K1JT. JT65 has 3 submodes: JT65A, JT65B, and JT65C. The most popular submode of JT65 is JT65A. JT65 gets '65' from the 65 tones it uses.
I/Q Raw Recording
Audio Sample
JT65 is an amateur radio QSO communication protocol developed by Joe Taylor, K1JT. JT65 has 3 submodes: JT65A, JT65B, and JT65C. The most popular submode of JT65 is JT65A. JT65 gets '65' from the 65 tones it uses.

Each transmission begins at t = 1s after the start of a UTC minute and finishes at t = 47.8 s. Each transmission must begin within the first 4 seconds of the minute to be decoded. Multiple stations transmit on the same carrier using both FDM and TDM methods. Initiating stations choose either the Even or Odd minute to transmit, and responding stations transmit on the opposite minute.

A sync (low) tone is to mark the lower boundary of each station's signal. The synchronizing tone is at 1270.5 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. The initiating station is responsible for choosing an offset that does not conflict with another station's signal. JT65 uses 126 contiguous time intervals, each of length 0.372 s (4096 samples at 11025 samples per second). Within each interval the waveform is a constant-amplitude sinusoid at one of 65 pre-defined frequencies, and frequency changes between intervals are accomplished in a phase-continuous manner.

Submodes[edit]

The three main submodes , JT65A, B, and C, differ in the frequency shifts between each of the 65 tones. For JT65A, the shift is 2.7 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. For JT65B, its 5.4 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. For JT65C, its 10.8 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. The general rule used is the resolution function 2.7m, where A uses m=1, B uses m=2, and C uses m=4.

Two experimental submodes, JT65B2 and JT65C2 are twice as fast as their counterpart JT65B and JT65C respectively. The tone frequency shifts are the same.

Samples[edit]

JT65A JT65B JT65C
JT65A.png
JT65B.png
JT65C.png

JT65B2 JT65C2
JT65B2.png
JT65C2.png

Frequencies[edit]

The signals are usually found in the data portion of the Amateur Radio Bandplans between the CWContinuous Wave (Morse) and the PSKPhase-Shift Keying/RTTYRadio TeleTYpe windows. They are always transmitted in USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables) mode regardless of band.

The most popular JT65A frequency is in the 20 Meter band.

  • 160m: 1838.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 80m: 3576.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 40m International: 7039.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 40m USA: 7076.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 30m: 10139.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables).
  • 20m: 14076.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 17m: 18102.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables).
  • 17m Alternate: 18098.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 12m: 24917.0 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)
  • 6m EME: 50276 kHzKiloHertz (kHz) 10^3 Hz USBUpper Side Band Modulation (Radio, referring to reception and modulation mode)Universal Serial Bus (Computer, referring to USB Ports and cables)


Decoding Software[edit]

Hobby Level Software

Video Examples[edit]

Additional Links[edit]


Additional Images[edit]