On 2/2/2021 3:48 PM, Steven Franke via wsjt-devel wrote:
Increasing or decreasing the width of the search window will increase/decrease the number of spurious candidates, so a larger search window means longer total decoding time and higher false decode rate. That’s why we advise users to narrow the search window to the smallest width that makes sense for the purpose.
Makes sense. More questions, which came up first time I tried to use FST4 on 160M, set up at 1839 kHz dial, 1050 Hz offset (I have a trash intermod carrier at 1840). If I set my K3 DSP IF (2.8 kHz roofing filter) for 3.2 kHz, normal for most WSJT-X modes (or even 2.8 kHz), AGC (and dynamic range) can be dominated by strong FT8 signals. As a retired serious pro audio guy, I have long understood the implications of phase shift from high Q filters, but it does seem that either 1) 1839 is not a great choice or 2) I may need to judiciously set the HF corner a bit lower.
Next thought. I called CQ for quite a while set for FST4-60. No responses, but a guy near Phoenix (I'm near SF) posted me to PSKReporter, probably unattended. My question is with respect to decoding, if I set up for FST4-60, would I also decode shorter period FST (and vice versa)?
Also interesting, I saw several 15 sec sequence signals around 1050 and 1150s kHz offset, which seems awfully low for a station using 1840 as a carrier frequency. I didn't bother to go to FT8 to figure out what they were running.
Started out with 5W, was -8 near Phoenix. Looking for mode decodes turned on the amp to get to 225W, now +8, almost exactly as expected, 30 min late a +4 decode. I've done enough on 160M with RBN testing antennas to know that's QSB.
Final thought -- some of this ought to be added to doc for FST4. My definition of a FAQ is what the author of the doc forgot. On principal, I don't read FAQs, I read doc and manuals.
73, Jim K9YC _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
