Both the Inrad and Elecraft filters use crystals that are hand- screened for low IMD. We built several high-performance test fixtures for ourselves and Inrad to make sure this was done consistently.
A slight improvement may be possible, but it would probably double the cost of the filters. The K3's receive IMD numbers are already excellent. 73, Wayne N6KR On Dec 31, 2010, at 2:00 PM, juergen wrote: > Hi Bill > > I understand the differences in IF frequencies. > > The question still remains, how much extra IMD dynamic could be > squeezed from the K3 if high performance 8mhz roofing filters were > used. We have seen no data on the K3 filters that quantified their > impact on IMD dynamic range. > > PA3AKE has shown that careful selection of crystals and building a > roofing with due care contributes a significant amount to the > ultimate IMD dynamic range. > > http://www.xs4all.nl/~martein/pa3ake/hmode/roofer_intro.html > > I wonder if a company like Network Sciences did build an improved 8 > mhz filter how much performance increase we would see. Surely if a > 20db jump in IMD dynamic range can be achieved at 70mhz, imagine > what the improvement would be at 8mhz! We will never know unless > someone tries. > > 73 > John > > > --- On Fri, 12/31/10, Bil Tippett <[email protected]> wrote: > >> From: Bil Tippett <[email protected]> >> Subject: Re: [Elecraft] Latest Sherwood table >> To: [email protected] >> Date: Friday, December 31, 2010, 4:18 AM >>> I wonder how such a high >> performance filter would work in the K3? >> Not that its >> needed in the K3. However in the interest of science, >> it might be a worthy >> pursuit. It also might push the K3 well ahead of the FT5000 >> in ultimate >> performance. >> >> Not very well since it's at 70 MHz. ;-) The >> Inrad filters are >> already better than whatever is in the FT5000 since >> Sherwood measured >> ultimate rejection in the K3 at 105 dB vs 90 dB for the >> 5000. >> >> 73, Bill W4ZV >> >> >> >> >> ______________________________________________________________ >> 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 >> > > > > ______________________________________________________________ > 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 ______________________________________________________________ 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
