Discussion in 'Working Different Modes' started by KC0BUS, Oct 14, 2016.
What can JT65 do that PSK31 can't do? What can JT9 do that JT65 can't do?
JT65 and JT9 are essentially identical from an operating standpoint. Actually, if you are using WSJT-X and have it set for simultaneous use of JT-9 and JT-65, the only difference you will see is the signal bandwidth on the waterfall display.
JT is basically only for exchanging and confirming locations and signal strengths. PSK-31 allows real time QSOs, just like you could have on RTTY using a keyboard and display. JT is limited to 13 characters per transmissions in 1 minute increments. PSK31 doesn't have length or time restraints.
I see. If RTTY does the same job that PSK31 does, then why did we need PSK31 invented?
JT's Web site says ... JT65 is for VHF and above. JT9 is better below about 17 meters.
Also, JT65 takes up 10 times the bandwidth of JT9.
PSK uses a tiny fraction of the bandwidth used by RTTY. It carries better for a given power level and antenna, as well as making more efficient use of spectrum.
This is a good site to visually differentiate the different digital modes http://www.sigidwiki.com/wiki/Database On there you can both see and hear the difference between RTTY, psk31, JT65, JT9 and darn near every other type of transmission that has ever been identified.
Work across the pond reliably on 10-20w when pretty much nothing else will get through. Decode signals at -28 to -30db that you can't even hear. Best of all, it avoids chats and prolonged QSOs LOL!
While that was true originally when it was designed for moon bounce ops, that is not the case today with the HF versions available.
Respectfully, that's hard to believe. The author of both modes (Joe Taylor, K1JT) clearly states otherwise on http://physics.princeton.edu/pulsar/K1JT/ :
WSJT-X implements JT9, a new mode optimized for weak-signal communication on the LF, MF, and HF bands. JT9 is about 2 dB more sensitive than JT65 and uses less than 10% of the bandwidth. http://physics.princeton.edu/pulsar/K1JT/wsjtx.html
Take a look around. JT-65 is far more popular on HF than JT-9 is.