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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=814270618-12032007>Hi
All,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=814270618-12032007>What
would be the advantages/disadvantages of having the preselector switched by
relays or some sort of semiconductor switches?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007>(Besides the obvious ones like e.g. mechanical size,
power handling, switch-over times to name a few)</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007>??</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007>Henry.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=814270618-12032007></SPAN></FONT> </DIV>
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style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
hpsdr-bounces@hpsdr.org [mailto:hpsdr-bounces@hpsdr.org] <B>On Behalf Of
</B>FRANCIS CARCIA<BR><B>Sent:</B> maandag 12 maart 2007 14:43<BR><B>To:</B>
hpsdr@hpsdr.org<BR><B>Subject:</B> [hpsdr] preselectors<BR><BR></FONT></DIV>
<DIV>Hi all,</DIV>
<DIV>I looked at the schematic of my Cubic prepost selector and it is quite
complicated. It has an 8035 processor to select the relays controlling Silver
mica caps and 3/4 inch square package adjustable inductors. The board is about
10 by 12 inches packed with 1/4 crystal can relays and control parts. This is
well above the scope of out board profile. </DIV>
<DIV>A good preselector to check out is the Cubic R3030. You can download the
manual from bama or premium RX. It uses pin diodes for higher bands and relays
for low. Also has a CP640 grounded gate fet amplifier. The R3030 MDS is about
-136 dBM.</DIV>
<DIV>I think it has about 10 filters to cover 15 KHz to 30 mhz. It takes 4
bits to a local decoder to select the correct filter. The can inductors
could be replaced with torroids. The L vales are on the schematic. The board
is about 4 by 6 inches. fc</DIV></BLOCKQUOTE></BODY></HTML>