Table 2 of the ARRL review finally answered my questions about the relative performance of the 2700 and 2800 Hz filters at 1 Hz and 2 Hz spacing. The results are very impressive. Can someone explain to me why the above/below results for these two filters are so disparate at these narrow spacings? The review suggests that the observed asymmetry is quite unusual. Is the performance of a radio most accurately described by the larger or the smaller of the above/below values? Is the asymmetry due to a design problem in the roofing filters or something in the K3 circuitry? If the asymmetry could be corrected by a change in roofing filter design, would the above/below values both become similar to the average of the two values? For instance, would the 94/81 IMD values at 1 kH spacing for a redesigned 2800 Hz filter approach 87.5/87.5, which would be a truly spectacular result for a radio with a single 2800 Hz roofing filter.
Doug N0HH (K3/10 #1213) _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
