I Love my K3+(new syn)! 73, Henry - K4TMC (K3 #98)
On Fri, May 28, 2021 at 1:22 PM BRUCE WW8II <wa8...@gmail.com> wrote: > I LOVE my K3s > > Bruce > WW8II > > On Fri, May 28, 2021 at 12:31 PM Wayne Burdick <n...@elecraft.com> wrote: > > > Sherwood has posted his measurements of the K4D's receiver performance in > > his table: > > > > http://www.sherweng.com/table.html > > > > We're quite pleased with his test results, which confirm that the K4/K4D > > is near the top of its class (direct-sampling SDRs). A K4HD would provide > > somewhat higher dynamic range for those stations in extreme signal > > environments, but the vast majority of operators will find that the > K4/K4D > > more than meets their needs. > > > > I'd like to highlight a few important items in Rob's chart. > > > > First, the K4D has a high 2 and 20 kHz dynamic range value of 101 dB. > > Because it's a direct-sampling radio, this figure will hold at nearly all > > offsets from strong signals. Second is the block dynamic range number > (128 > > dB), higher than almost every other "pure" SDR measured. Finally, there's > > the LO noise (local oscillator; 148 to 155 dB) -- again, very favorable > > compared to all competing SDRs. This is an important number correlated > with > > reciprocal mixing dynamic range (RMDR). > > > > Taken together these demonstrate that the K4D will offer excellent > > performance in crowded band conditions. > > > > Inevitably a question will arise regarding the chart position of the K4D > > relative to a couple of our other transceivers: the K3S and KX3. There's > a > > bit of "apples to oranges" in both comparisons. > > > > The K3S uses a superhet receiver architecture. The K4HD will provide a > > receive setting that emulates this superhet performance when and if it's > > needed. But the "pure" (direct sampling) method used by the K4 (all > models) > > has many advantages. One is the elimination of artifacts associated with > > crystal filters. Another is that, as a pure SDR, the K4 has a far more > > flexible architecture. We'll be able to provide updates to the receive > and > > transmit digital signal chains that cannot be added to a superhet like > the > > K3S or its competitors. > > > > The KX3 is another Elecraft radio high on Sherwood's chart. Its > > performance is excellent, especially at its price point. But its numbers > > relative to the K4 are somewhat misleading, as hinted at by Rob's > > footnotes. The KX3 uses a quadrature downsampling architecture, which > > digitally samples at baseband audio rather than at RF. This is ideal for > a > > radio like the KX3 that has to have very low current drain for portable > > operations. The K4 uses a direct-samping architecture that requires a > > higher power digital signal chain, resulting in important benefits over > > quadrature downsampling including much higher and more consistent > opposite > > sideband image suppression and 2nd-order intermod rejection. So the two > are > > really designed for different applications. > > > > Overall, this first independent test of the K4 validates the performance > > of our SDR architecture. Feel free to send us any further performance > > questions. > > > > 73, > > Wayne > > N6KR > > > > > > ______________________________________________________________ > > 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 wa8...@gmail.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 kilo4...@gmail.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
