On 10/6/2010 5:15 PM, Scott Ellington wrote: > There does indeed seem to be something funny about the 400 Hz filter.
There are several issues. First, every 8-pole CW filter I've measured has significant offset, and needs to be compensated, just like the 5-pole filters. 100 Hz is typical. Second, what you are probably measuring is the CASCADED response of the 400 Hz filter and the DSP IF filters that you have set. It is entirely normal for that cascaded bandwidth to be less than 400 Hz. There are filter measurements on my website. To see the bandwidth of the 400 Hz filter, you must set the IF filter much wider than 400 Hz (like 1kHz) and tell the K3 that the 400 Hz filter is a 1kHz filter. That will cause the400 Hz filter to be switched in at 1kHz bandwidth. There are some filter measurements on my website. http://audiosystemsgroup.com/K3FilterStudy-250HzRoof.pdf 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
