When propagation is really bad JT9 can still save your QSO. However, don't forget that FT8 would only decode till -20dB. Now, with the new mode FT8 this all sounds a little silly. According to Wikipedia, JT65 uses 65-tone MFSK (Multiple Frequency-Shift Keying), whereas JT9 uses 9-tone FSK (Frequency-Shift Keying) probably hence the numerals in the respective names.
Jt9 vs jt65 free#
Henk wrote a nice article about it and posted a 6T9 logo on his site. You are free to use this logo anywhere you want to promote JT65 to JT9. Henk PA2S and Steve GM0HUU contributed with the invention of 6T9. Hopefully this post will contribute to the migration from JT65 to JT9.
Besides that, on 60m, british stations are not allowed above 1000Hz in the waterfall and do call/listen with JT9. source: specifications JT65A/JT65/JT65-HF mode is normally used on HF, MF, LF and 6 meter bands. The system allows approximately +/-600Hz auto-tuning on receive. The lowest tone of the JT65 signal is normally 1270Hz. JT65A signal bandwidth extends about 200Hz above 1270.5Hz sync. Q65 offers submodes with a wide range of T/R sequence lengths and tone spacings it is highly recommended for EME, ionospheric scatter, and other weak signal work on VHF, UHF, and microwave bands. Sync tone is the reference mouse-click frequency for JT65. As with modes such as PSK31 and WSPR, you interface your HF rig to a computer, and send out text. It’s also great for making contact over distance with low power, where a voice signal just can’t make the trip. Icom version for transceivers with 13 Pin Din Accessory Connector. JT9 can have ten-times the signals but decoding of overlapping signals is much less likely to happen. JT65 is one of the more specialist data modes that I’ve played with, but I must admit, it’s quite addictive. The JT65 sub-band can often be seen with multiple overlapping signals and they usually decode correctly. JT9 is much better for spectrum efficiency and uses less power due to narrower bandwidth.
JT65 takes up just under 180 Hz and about 16 Hz for JT9. It is about 2 dB more sensitive than JT65 while using less than 10 of the bandwidth. Differences between JT65 & JT9 are bandwidth and signal reports. Did you know for instance that it is possible to receive JT65 and JT9 on the same frequency, especially important because there is no JT9 allocation on 60m and 6m. JT9 is optimized for the MF and HF bands. Strangely enough I still see few on the even more sensitive mode JT9. The JT65 frequencies are going to be overcrowded. Henk PA2S has mentioned it at the start of this year.
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