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<DIV>Alexander</DIV>
<DIV> </DIV>
<DIV>50 micro volts = -73 dbm (S-9) when using the XG-2 </DIV>
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<DIV>73 de Joe K1RQG</DIV>
<DIV> </DIV>
<DIV>In a message dated 2/28/2009 2:00:42 P.M. Eastern Standard Time,
alexander.geckeler@gmx.de writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" face=Arial color=#000000 size=2>*****
High Performance Software Defined Radio Discussion List *****<BR><BR>Hello
Ben,<BR><BR>thanks for your suggestions.<BR>I bought an Elecraft XG-2 and will
use it as a signal source.<BR>At what what output level it should be used -
1microV or 50 microV to <BR>calibrate
Mercury?<BR><BR>Alexander<BR><BR><BR><BR>-------- Original-Nachricht
--------<BR>Betreff: [hpsdr] Mercury Level Cal<BR>Datum:
Sat, 28 Feb 2009 13:42:31 -0500<BR>Von: W4sc
<www4sc@alltel.net><BR>An: HPSDR Reflector
<hpsdr@hpsdr.org><BR><BR><BR><BR>***** High Performance Software Defined
Radio Discussion List *****<BR><BR>All,<BR><BR>In level calibration of Mercury
RX, be aware of the following that may<BR>leave you with a less than optimal
calibration. A good, consistant<BR>calibration could not be obtained while
attempting on 14.2MHz at -70dbm.<BR><BR>If you use a signal generator
connected via a cable, make sure the<BR>inter-connecting cable is of good
quality and condition and no longer than<BR>required. In the specific
case, it was determined that the interconnect<BR>cable (RG-58) had a bad
connector, and the shielding effectiveness was not<BR>good enough. Leakage
into the setup from external sources (ie computer<BR>clocks, and
general<BR>electrical noise, external radio signals ect, ect.) should be
eliminated.<BR>Level calibration was being attempted on 14.2 MHz, and in this
particular<BR>case the 20M band seems rife with computer and other external
noise.<BR>Possibly due to the 14.314MHz crystal osillator within the host
itself.<BR><BR>Level calibration was eventually performed at 15MHz, first at
-70dbm, then<BR>at -90dbm.<BR><BR>The following is suggested to mitigate this
leakage problem:<BR><BR>1) Use a good quality inter connect cable, such as a
double shielded RG-142<BR>This can give about 20db better isolation over RG-58
type cable.<BR>2) Use the Elecraft signal generator (XG1 or XG2) connected
directly to<BR>Mercury.. This will eliminate the interconnect. Be sure of the
SGx output<BR>level. This setup may also benefit from having a shield
around the<BR>generator.<BR>3) Find and use a "quiet" frequency.<BR><BR><BR>de
Ben W4SC<BR></FONT></BLOCKQUOTE></DIV>
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