Hi Jim,
2.7 kHz 5-pole. I have added this information to my chart. 73, Adam VA7OJ/AB4OJ From: Jim Bolit [mailto:jbol...@outlook.com] Sent: 15-Sep-15 05:13 To: Adam Farson; 'Johnny Siu' Cc: Elecraft List Subject: RE: [Elecraft] K3 to IC-7800 Comparison? Adam, Please confirm what roofing filter was used for your test on the K3. Tnx Jim W6AIM . -------- Original message -------- From: Adam Farson <far...@shaw.ca> Date: 9/14/2015 3:14 AM (GMT-06:00) To: 'Johnny Siu' <vr2...@yahoo.com.hk> Cc: Elecraft List <elecraft@mailman.qth.net> Subject: Re: [Elecraft] K3 to IC-7800 Comparison? Hi Johnny, The K3 with the KSYN3A is in a closely-packed cluster of radios which score highest in the NPR test. Its exact ranking depends on which test frequency is being compared. The differences are very slight, mostly within a couple of dB. In practice, I regard an NPR value of 80 dB or higher as excellent. 73, Adam VA7OJ/AB4OJ From: Johnny Siu [mailto:vr2...@yahoo.com.hk] Sent: 14-Sep-15 00:54 To: Adam Farson; Elecraft List Subject: K3 to IC-7800 Comparison? Hello Adam, From reading of your NPR chart, could I understand that apart from IC7851, the K3 (with new KSYN3A installed) is the second best in terms of NPR test? 73 Johnny VR2XMC _____ 寄件人︰ Adam Farson <far...@shaw.ca> 收件人︰ Elecraft List <elecraft@mailman.qth.net> 傳送日期︰ 2015年09月14日 (週一) 2:51 PM 主題︰ Re: [Elecraft] K3 to IC-7800 Comparison? 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 <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 jbol...@outlook.com ______________________________________________________________ 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
