Although it is not shown on the graph nor in the text, the ARRL report shows the noise in dBc/Hz, i.e. a bandwidth of 1 Hz. This must be adjusted to the appropriate bandwidth. Add 27 dB to get to 500 Hz and about 33 dB to get to a typical SSB bandwidth.
And the worst noise is about -110 dBc/Hz out about 350 kHz from the carrier. Add 33 to that and you get -77 dBc as shown by SM5BSZ.
And the one poster the other day who claimed his Flex 1500 did not have have this issue is incorrect. According to the ARRL lab reports *ALL* Flex models are afflicted.
73 de dave ab9ca/4 On 12/30/13 8:34 AM, Rick Stealey wrote:
With regard to SM5BSZ's SDR wideband-noise performance table (http://www.sm5bsz.com/dynrange/dubus313.pdf):Something doesn't jive with the table in the above report. I spot checked by looking up the Flex5000A in July 2008 QST, fig 3. QST shows wideband noise never gets worse than -120dbc, although the report says it is -77 at 350 KHz. And (as I remember) the K3 report from QST showed phase noise way out at the extremes of the meausrement dropping off much more than this author reported, down into the range of -155 db. Am I reading something wrong? Apparently this report is not recent because the worst performer of late (from QST measurements) has been the FT3000. Too bad SM5BSZ didn't comment on it. Rick K2XT ______________________________________________________________ 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 .
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