Hi Edson, Signal strengths reported by JT65 have always maxed out at -1 dB. (Indeed, they start compressing and are significantly nonlinear above -10 dB or so.) The reason is historical: JT65 was developed for EME, where the SNR in 2500 Hz BW is essentially never greater than 0. As originally defined, the JT65 protocol supports signal reports from -1 to -30 dB.
JT9 uses (almost) the same source encoding to compress user messages into 72 bits. But it was developed for use st MF and HF, where signals can be much stronger. By co-opting some code ranges otherwise used for grid squares near the North or South poles, JT9 supports signal reports from -50 to +49 dB. You'll find some relevant information here in the User Guide: http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main-1.7.0-devel.html#_standard_exchange : "JT65 reports are constrained to lie in the range –30 to –1 dB, and values are significantly compressed above about -10 dB. JT9 supports the extended range –50 to +49 dB and assigns more reliable numbers to relatively strong signals." -- Joe, K1JT On 12/22/2015 11:54 AM, Edson W. R. Pereira wrote: > Hello everyone, > > I have been monitoring using wsjt-x v1.7.0 r6286 and am noticing that the > JT65 decoder is not showing signal strengths stronger than -1 dB. Even with > very strong signals the decoder shows -1 dB. The JT9 decoder does show > signal strengths above 0 dB. > > Has anyone noticed this? > > 73 and season's greetings, > > Edson PY2SDR > > --- > - We humans have the capability to do amazing things if we work together. > - Nós seres humanos temos a capacidade de fazer coisas incríveis se > trabalharmos juntos. > > > > > ------------------------------------------------------------------------------ > > > > _______________________________________________ > wsjt-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/wsjt-devel ------------------------------------------------------------------------------ _______________________________________________ wsjt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wsjt-devel
