How is it possible to compare the dynamic range of a direct conversion radio with a superhet, where a mode-specific filter can be placed at the first mixer, with the expectation that direct conversion would give similar dynamic range as a superhet?
I haven't heard yet a technical way to explain this, especially given how Wes Hayward defined how to measure receiver dynamic range many years ago. 73, Will, wj9b CWops #1085 CWA Advisor levels II and III http://cwops.org/ -------------------------------------------- On Sun, 12/24/17, Joe Subich, W4TV <[email protected]> wrote: Subject: Re: [Elecraft] IC-7610 added to Sherwood's list To: [email protected] Date: Sunday, December 24, 2017, 5:03 PM On 12/24/2017 5:32 PM, Don Wilhelm wrote: > The real shocker is the BDR: only 119 to 122 dB. That’s 30 dB weaker > than the K3S and only 1 dB better than the IC-7300. My guess is that the "Front end selectivity" is not an "A tracking preselector" but rather a "B Band Pass" and that the bandpass is wider that that of the 7300 in order to support the "dual RX" capability of the 7610. It's either that or the design/hardware has some significant bugs. The other explanation would be simply that direct sampling SDR has a far wider measurement variability than traditional receiver topology. Note the 12 dB difference in IMDDR3 between Flex 6700 on 9/29/14 and the Flex 6700 measured on 3/17/17. 73, ... Joe, W4TV On 12/24/2017 5:32 PM, Don Wilhelm wrote: > Rob’s IC-7610 RX performance measurements are now posted, at > sherweng.com. The ‘7610 came in twelfth on his list. > The real shocker is the BDR: only 119 to 122 dB. That’s 30 dB weaker > than the K3S and only 1 dB better than the IC-7300. I guess no one is > using these rigs in high-signal conditions. > > Bragging rights for the K3, KX3 and K3S owners. > > 73, > Don W3FPR > ______________________________________________________________ > 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 > Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected] ______________________________________________________________ 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 Message delivered to [email protected]
