Hi Don, I concurr with Don on his analysis.
I have a 700hz and 200 hz filter and I use them quite a bit for PSK31. If you try to use just the DSP to narrow down the bandwith it does not work as well. I used to only have a 2.7 and 2.1 k hz filters and used the DSP only. However after using the narrow filters my receive on weak signals has improved a lot. Now on the transmitt side of things there are many times that even thought I can hear them I am not able to work them. Part of this is probally due to my receive being more efficient than my TX with my dipole. Also are you using Data A mode and not SSB. Plus you need to turn off much of the noise reduction to make PSK work. I find that I have to go to between 30 and 40 watts to make contacts with my K3 and dipole. I tried to work some of the special events but only got one on PSK and one SSB, but I did not try very hard. Plus they had a lot of traffic. Hope this helps Now its Don Cubed! Don KD8NNU On Tue, Jul 5, 2011 at 8:02 PM, Don Wilhelm wrote: > Don, > > What is your specific problem? If it is strong signals within the > passband, then more narrow roofing filters are the answer. Instead of > using the entire 2.7 kHz bandwidth and depending on the software > application to resolve any one signal, use the K3 filtering to zero in > on a specific signal, and you will find the decoding much better, with > or without the presence of noise. > > Yes, what I am suggesting is that you first reduce the bandwidth of > the K3, and then the PSK31 software has fewer signals to deal with, > and can decode them better. > > I know that most PSK31 operators just use the full SSB bandwidth and > let the software resolve the signals. While that works when all those > transmitting PSK31 keep their power down to a reasonable level, there > are those few who insist on being "band hogs", and transmit at 100 > watts plus. PSK31 can be very effective when used at 15 to 25 watts, > and many do keep it at that - but Special Events and contests, I find > that some crank up the power, and decoding for everyone else on the > band suffers. > > The K3 with its roofing filter selection and DSP filtering can help > greatly, but to take advantage of that, one must reduce the bandwidth > of the K3, and that means not using the full spectrum waterfall > display -- use the K3 VFO to move from signal to signal, and your > decoding will be greatly improved. > > 73, > Don W3FPR > > On 7/5/2011 7:39 PM, Don Putnick wrote: >> After having a less than successful time with PSK31 during the 13 >> Colonies Special Event, I think I need to learn more about noise >> reduction. I've read the section in KE7X's manual, but I'm looking >> for guidance specific to the soundcard digital modes. >> >> 1) It appears the K3's attenuator is fixed at -10 dB. Is that the >> case or is it reprogrammable? >> >> 2) What is the collective wisdom on noise reduction for soundcard >> digital modes: K3 attenuator, K3 noise reduction, PSK31 software >> noise reduction, some combination of the three, or none at all? >> >> Thanks and 73, >> Don NA6Z K3 #5495 >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
