<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Rod, <div><br></div><div>When using Hermes (or a single Mercury) with multiple receivers operating the Alex filters are switched according to whether you have selected automatic Alex switching or manual Alex switching. </div><div><br></div><div> If in automatic mode, the HPFs (the filters on the Rx Alex fliter board) are switched to the high pass filter appropriate for the lowest frequency of the multiple receivers and the LPFs (the filters on the Tx Alex filter board) are switched to the low pass filter appropriate for highest frequency being used by the multiple receivers, except on transmit in which case the LPFs are switched to the filter appropriate for the transmit frequency. </div><div><br></div><div>This arrangement allows all bands that are being used by the multiple receivers to pass through Alex, automatically. </div><div><br></div><div>In manual Alex switching mode the filters are switched according to how you have set the frequency limits on the manual Alex setup menu. </div><div><br></div><div>If your Alex filters are not switching in this manner then further examination is indicated to determine why not. </div><div><br></div><div>73, Joe K5SO</div><div><br></div><div><div><div>On Dec 1, 2012, at 10:42 AM, Rod Brink wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">***** High Performance Software Defined Radio Discussion List *****<br><br>
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<div><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt">I got to wondering
how Hermes (or Mercury) would behave when Alex is used and multiple Rx operation
is invoked. In Rx the antenna signal is routed first through the Tx LPFs
and then through the Rx bandpass filters. So the question is: if each
receiver is tuned to a different band, which set of filters is
selected?</span> <!--?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" /--><o:p></o:p></p></div>
<div><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt">I ran a little
test. I don't have the Rx bandpass filters, only the Tx LPFs but am
certain the behavior is the same. What seems to happen is that initially
the filter corresponding to VFO A is selected. When the cursor is moved to
a different band on the panadaptor <strong><span style="FONT-FAMILY: 'Verdana','sans-serif'">and the frequency is
changed</span></strong> the filters are instantly switched to that
band.</span> <o:p></o:p></p></div>
<div><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt">Under these
conditions signals on all receivers cannot be simultaneously seen on the
panadaptor. They <strong><span style="FONT-FAMILY: 'Verdana','sans-serif'">would</span></strong> be were it not
for Alex's bandpass filters getting in the
way.</span> <o:p></o:p></p></div>
<div><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt">Isn't the whole
purpose of multiple Rx operation to give contestors a view of signals
simultaneously occurring on multiple bands...?</span></p><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt">73,</span></p><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt">Rod,
KQ6F</span></p><p class="MsoNormal"><span style="FONT-FAMILY: 'Verdana','sans-serif'; FONT-SIZE: 10pt"></span><o:p></o:p> </p></div>
<div><p class="MsoNormal"> <o:p></o:p></p></div></font></div></div>
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