On 18/02/2017 07:47, Игорь Ч wrote: > Due to the current explosive growth of HF activity in JT65a mode we > are getting close to a date when existing JT65 bandwidth will be fully > utilized leaving no possibility for weak signal communication but > local contacts. > . > It might be right time now to act towards the new concept for JT65 HF > usage and spectra allocation, considering latest SDR technology for > handling 20kHz bandwidth in the software.
HI Igor, although this is technically possible with average PC sound card sample rates it would tend to exclude those with SSB only rigs who would have to move around just to see which stations are active. I believe this would create a DX cluster type herd mentality with most stations landing on the band segment that has the rare station on. One of the things I really like about JT modes on HF is that QSOs are almost exclusively initiated from on air calls, the ability of everyone to potentially copy everyone is fantastic. Even though it is all about computers and the Internet adds huge benefits, the fundamental principles of listening on air for QSO partners is one reason for the success of the JT modes on HF IMHO. Another matter to consider is that on most HF bands there is simply not enough bandwidth available to spread the JT modes out by a factor of five. Take 40m for example, here in the EU we are operating in the phone band which itself is busy as the solar minimum is approaching (a solar minimum that is forecast to be longer and deeper than most operators have experienced), pressures on spectrum space will undoubtedly increase if the hobby is to succeed and proposals to grab more for any operating mode will not be well received. If a few more stations shifted to JT9 on HF, the potential spectrum utilization gains are similar without requiring many to buy new rigs. Admittedly JT65A on HF has reasonably good overlapping signal decoding which is greatly enhanced by two pass decoding. This is an area that has not been taken advantage of for JT9 yet, when the utilization of JT9 becomes high enough to justify it I'm sure that a win is there to be had by using two pass decoding. Perhaps the near capacity JT65A utilization at times will encourage more to experiment with new bands and JT9 on HF. There is still a lot of space for us all within a conventional SSB bandwidth (plus a bit if you have 4 or 5kHz Rx capability) on each band. Imagine what might happen if everyone who uses JT65A on HF switched to JT9, I doubt we would be looking for more spectrum space for some time. Just my 2c 73 Bill G4WJS. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ wsjt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wsjt-devel
