On 9/30/2010 10:45 AM, Don Cunningham wrote: > I use the 400hz 8 pole filter for RTTY, for PSK 31 you will probably want to > see the whole range of avaliable stations, so the SSB filter would be better > in my mind. Not necessarily. While using a wideband 2.7kHz IF and letting the PSK31 decoding software do the filtering in DSP is certainly the most common way to work PSK31, you can gain a lot of signal to noise ratio by using a very narrow IF filter. This would be especially useful under tough noise conditions or heavy QRM.
It's also important to realize that the optional filters you buy are ROOFING filters that protect the IF from overload by strong signals in its passband, which can be QRM or QRN (either local noise or static crashes). IF filtering is provided by DSP, so you can set anything you want by turning a knob. Seasoned operators have generally settled on the stock 2.7 kHz filter, the 1.8 kHz filter for serious SSB contesting or DXing, and the 400 Hz filter for CW. Those who are even more serious contesters also use the 250 Hz filter for CW and RTTY. That's the collection I use. Filters are easy to add later if you only have one RX, so 2.7 kHz plus 400 Hz is a really good starting point. If, however, you have the Sub RX installed, you want to do it right away, because it is a real PITA to do ANYTHING inside the radio, even something as simple as changing filters. That's because the sub-RX is a real "shoe-horn job." 73, Jim K9YC ______________________________________________________________ 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
