Hi Phil, Just to clarify: Both the KX3 and K3/K3S are SDRs. A major difference between these rigs and something like the IC-7300 or Flex 6xxx series is that our A-to-D converters (ADCs) are protected from wideband interference by a narrowband I.F. The K3/K3S uses crystal filters, while the KX3 uses precision, narrowband low-pass filters.
In direct-sampling SDRs, the ADC is right at the front end of the radio, protected only by wideband LC filters. The result is typically 15-20 dB lower blocking dynamic range. More subtle is the effect of multiple signals, which can combine in phase to hit the limit of the ADC, resulting in unwanted images. It's a tradeoff; a direct-sampling SDR can allow you to look at multiple MHz of bandwidth on its spectrum display, if that's of interest. Wayne N6KR On Sep 3, 2015, at 2:57 PM, Phil Wheeler <w...@socal.rr.com> wrote: > Joe, > > Thanks for addressing what to me is the core issue with any rig -- > performance. A "bells and whistles" user interface -- and that can be a > matter of personal preference -- may sell a lot of rigs, but to me > performance is key in selecting a base station transceiver. I can compromise > performance for special applications like portable ops, QRP, etc. but I want > my main station radio to be near the top of the list in the Sherwoodian sense. > > After looking at the information here > http://www.icomamerica.com/en/products/amateur/hf/7300/default.aspx an in the > pdf file linked here: > http://www.icomamerica.com/en/downloads/DownloadDetails.aspx?Document=746 > and from the general appearance of the Icom-7300 (ports, controls, etc.) I > don't expect it to be near the top when Rob Sherwood tests it. Of course, it > hinges on a number of factors -- including those you brought up below -- and > I could be surprised. Even so, while I'm not spring-loaded against SDR rigs > (the KX3 is basically an SDR radio, after all, and I enjoy mine), I can do > without a touch-screen interface. But I've been at this for 62 years now, so > maybe I'm just "old fashioned" :-) > > 73, Phil W7OX > > On 9/3/15 1:39 PM, Joe Subich, W4TV wrote: >> >>> I think this is Icom's way of dipping their toe in the water and not >>> upsetting their fan base by introducing an SDR in convention looking >>> hardware. I am confident that they will be releasing a whole line of >>> stand alone SDR rigs... >> >> The question will be what quality ADC Icom uses in the front end of the >> 7300 and how clean (phase noise) they can make the synthesizer (clock). >> >> If they have enough ADC bits to provide dynamic range, their claimed >> synthesizer phase noise comparison should put the 7300 at about the >> same level as the Ten-Tec Eagle in the Sherwood "chart" (e.g., 92-95 >> dB IMDDR3, -134 dBc @ 10 KHz phase noise, 125-130 dB 100 KHz blocking >> [ADC limited]). >> >> If Icom "cheaps out" and uses an ADC with limited resolution (number of >> bits) like some of its commercial products, the 7300 is likely to fall >> way down the list - into the neighborhood of the IC-7000 or FT-2000. >> >> 73, >> >> ... Joe, W4TV >> >> >> On 9/3/2015 3:19 PM, Wm Robert Leschyna wrote: >>> Personally I feel that a touch screen is a must in a "stand alone" (no pc >>> needed) SDR, as it allows the future development and or creation and use of >>> soft keys for functions that we may not even think of today. As for the >>> IC7300, most of the time you will likely be using the most commonly used >>> functions which appear to be tied the physical knobs and buttons, and not >>> have to touch the screen that much. >>> >>> SDR is the way of the future, heck it is the way now, and I think this is >>> Icom's way of dipping their toe in the water and not upsetting their fan >>> base by introducing an SDR in convention looking hardware. I am confident >>> that they will be releasing a whole line of stand alone SDR rigs... >>> >>> I have owned a K2 a couple K3s and KX3, I love Elecraft and love supporting >>> a made in North American brand, but frankly am confused as to why Elecraft >>> isn't leading the pack on stand-alone SDR? >>> >>> 73 >>> Bob > > ______________________________________________________________ > 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 n...@elecraft.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
