For Jim K9YC:
Hi Jim, Many thanks for the post on my presentations at the club meeting on Saturday September 5. To quote: "There's an important caveat to his work. The NPR measurements require very sophisticated band-stop filters in his instrumentation setup, and based on the filters he has been able to source, that limits the frequency range where he can do his measurements. An example is in the footnote for the Flex-6700, which has no preselector for the range where he had to do his measurements, which may have caused that radio to measure worse than it would on the ham bands." The instrumentation I use for NPR testing is re-purposed telecom test equipment, as described in my Web article and also in my article in QEX for March/April 2015. I rely on the surplus market for the test sets, and also for the filter pairs (bandstop and bandpass). The bandstop filters typically have 95 dB stopband attenuation and ~ 3 kHz stopband width. A number of these filters are on (or near) amateur bands, e.g. 1940, 3886, 5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz, so all the test data in my web article are on this frequency (which is in the 60m band). The Flex-6700 does not have a preselector for this band, so the noise loading will hit the front end and the ADC harder. This will degrade the NPR reading by a few dB, but it will show how the receiver behaves if heavily loaded on a band for which no preselector is fitted. As I picked up additional filters, the number of frequencies on which I run the test has steadily increased. Links to multi-frequency NPR data for various radios (including the K3 with KSYN3A) are on my website: http://www.ab4oj.com/test/main.html#NPR It was a pleasure meeting you guys over the Labour Day weekend. 73, Adam VA7OJ/AB4OJ ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com