New Mode for MF and LF

If you are on 160 meters, or perhaps on 472 or 137 kHz, you may be interested in a new mode called JT9, designed especially for making QSOs on these bands. JT9 uses the structured messages introduced in 2003 for the JT65 mode, now widely used for EME and for QRP operations at HF. JT9 can operate at signal levels as low as -27 dB (in a 2500 Hz reference bandwidth), with one-minute timed transmissions. It also offers slower transmissions of 2, 5, 10 and 30 minutes duration, and the slowest mode can decode signals as weak as -40 dB. With one-minute transmissions, submode JT9-1 has a total bandwidth of 15.6 Hz -- less than one-tenth the bandwidth of a JT65A signal. The other submodes are narrower still: a JT9-30 signal occupies about 0.4 Hz total bandwidth.

JT9 is implemented in an experimental version of WSJT called WSJT-X. Some further details can be found at ,
and an early version of WSJT-X can be downloaded from .

If you want to try JT9, I suggest using dial frequency 1838, which is also used for JT65A, PSK31, and MFSK. In default configuration WSJT-X allows transmission and reception 1 to 2 kHz above the dial frequency.

Please note: WSJT-X is in an early development stage. Your feedback (direct email to me is best) will be much appreciated. And feel free to email me for a sked!

-- 73, Joe, K1JT