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<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Dear Alfred,<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>My measurements
of the effect of Dither (and also of Random) in 2009 on a TAPR-Mercury show an increase
of the noise floor of about 4dB, see <a
href="http://openhpsdr.org/wiki/index.php?title=Mercury_-_intermodulation_(IMD)_tests">http://openhpsdr.org/wiki/index.php?title=Mercury_-_intermodulation_(IMD)_tests</a>
.<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Best 73 de Walter
HB9AJG <o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Alfred wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> Hi all<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> First, I
would like to add my congratulations for Phil Harman for this award!<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> I have
noticed a strange behavior of Mercury-EU, which might indicate an individual
board failure:<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> Antenna
input with 50 Ohms terminated, no antenna. When switching on Dither I notice an
increase in background noise level of between 7 and 11 dB depending on the
band! Typical noise value without dither is around -130dBm (slightly better
than tapr-mercury).<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> Doing the
same experiment on my two Tapr-Mercuries, the increase of noise is hardly
noticable with a value of 1 dB.<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>Since I don't
have two Mercury-EU, I can not compare.<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> Normally, I
am running the HPSDR with Dither off, so this is only a "theoretical"
problem, but it is interesting anyway.<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
lang=EN-US style='font-size:10.0pt;font-family:"Courier New"'>> Any
suggestions are much appreciated.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Courier New"><span lang=EN-US
style='font-size:10.0pt;font-family:"Courier New"'>> 73, Alfred, HB9EPU</span></font><font
size=2 face=Arial><span lang=EN-US style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></font></p>
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