WSJT-X i el mode JT9


El JT9 és un mode digital que permet rebre senyals extremadament febles. És ideal per a emetre amb potències molt baixes, de 5 W. o menys (QRP), en especial a les bandes d’HF. El programa WSJT-X pot emetre i rebre en dos modes simultàniament, el JT9 i el JT65-HF. Descarregueu el WSJT-X aquí.
WSJT-X implements JT9, a new mode designed especially for the LF, MF, and HF bands, as well as the popular mode JT65.  Both modes were designed for making reliable, confirmed QSOs under extreme weak-signal conditions. They use nearly identical message structure and source encoding. JT65 was designed for EME (“moonbounce”) on the VHF/UHF bands and has also proved very effective for worldwide QRP communication at HF; in contrast, JT9 is optimized for HF and lower frequencies. JT9 is about 2 dB more sensitive than JT65A while using less than 10% of the bandwidth. With either mode, world-wide QSOs are possible with power levels of a few watts and compromise antennas. A 2 kHz slice of spectrum is essentially full when occupied by ten JT65 signals. As many as 100 JT9 signals can fit into the same space, without overlap.
WSJT-X offers a “bi-lingual” operating mode in which you can transmit and receive JT65 and JT9 signals, switching between modes automatically as needed.  Displayed bandwidth can be as large as 5 kHz.  If your receiver has as upper-sideband filter at least 4 kHz wide, you can have all the typical JT65 and JT9 activity on screen at once, available for making QSOs with a click of the mouse.  Even with standard SSB-width IF filters, switching between JT65 and JT9 modes is quick and convenient. (K1JT)