On 7 Aug 2024 at 17:46, Hasan N0AN wrote: > I have been using Martin's settings on my 7300 for over a year. (I arrived > at these settings experimentally, collecting data on the number of decodes > per sequence in the presence of strong signals.) > > AGC FAST and audio level adjusted for about 55 dB on band noise, produced > the largest number of decodes per sequence, but AGC off and riding the RF > Gain was slightly more effective...but rarely worth the bother.
Hi Hasan (and Mike), you might be interested to know that the tests done by Rob Sherwood NC0B on his 7300 revealed that, with AGC off, it could tolerate a *very* much higher level of RF input signal than the 7610 before its audio output began to distort. I can't recall the exact figure but from memory I think Rob found that RF input levels of up to -20dBm were accommodated by the 7300 without any distortion appearing on the audio ouput. That equates to a signal of around S9+50dB, so on that basis the 7300 should be a better rig than the 7610 for operating with AGC off... The significant difference in AGC-off behaviour between the 7610 and the 7300 is presumably down to differences in the DSP and the post-DAC audio chain in the two rigs; it's a shame Icom didn't replicate that aspect of the 7300's design in the 7610. I have no knowledge or experience of other makes and models of rigs so can't comment on at what RF input signal levels their audio outputs might begin to exhibit distortion. Another factor to bear in mind is that by setting the audio level to give a WSJT-X 'thermometer' reading somewhere towards the upper end of its scale, eg. around the 65-70dB mark and then relying on the rig's AGC to keep the level below the soundcard ADC's clipping threshold as indicated by the 'thermometer' turning red, you're making best use of the full range of the ADC, ie. from near the top of its range down to where quantisation effects start to come into play. > BTW, Uwe's latest code, 240806, has lowered the threshold for decoding (in > practice) to -15 SNR for solid decodes and -16 for occasional decodes. > Prior versions were -14 for solid and -15 for rare decodes. Thanks for the tip-off, I'll give Uwe's latest version a try. -- 73, Martin G0HDB -- This email has been checked for viruses by Avast antivirus software. www.avast.com _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
