Over the past two months I've been enjoying weak signal low band DXing on good antennas with my K3 using roofing filters for CW (500Hz) and SSB (2.1 KHz) . My K3 has the latest DSP board and the firmware is up to date with the thirty-two(?) NR choices. What I'm finding is that the NR Firmware likes to see a wide bandwidth from which the weakest signals can be dug out of the in the noise on SSB or CW. If I narrow up the bandwidth with the optional filters I can't copy the signals as well. i.e. with NR enabled together a 2.1 or 500 Hz filter. I hear best with NR together with the 2.7 KHz filter. Interesting! This means that QRM must be considered as a secondary matter within the bandpass if the NR feature is to work at its best for me. I find different NR settings depending on band conditions and the ultimate setting varies with incoming signals. I've been working lots of JAs on 80 meters where the NR truly helps. The narrow CW/SSB filters are great but I don't use NR with them. Weak signal reception comes down to using the narrow roofing filters without NR. OR, just the 2.7 KHz wide filter with NR enabled. Yes, over and over, the 2.7 KHz bandwidth together with NR brings them out from the depths of ESP level to readable signals. So, why have the optional filters? I use them to get signals so I can copy them through QRM when the band is busy. . Happy Holidays
73, John, W1QS ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
