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<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009>------------------------------I plan to run my hpsdr
with an amplifier at full legal limit. I also want to be sure to maximize
receiver performance. Therefore, I've been concerned that there may be the
need to have the boardset well-protected, from an RF point-of-view, from
the external environment. </SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>First of all, does
anyone have practical experience with the importance of grounding and shielding
(or not) for hpsdr?-----------------------------</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>It´s taken me a
while to sort all the tx RFI problems at typically 1KW output. I´m not sure that
all the things I did were necessary but they possibly add up to sensible
precautions in a good installation.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>1) Merc/Pen/Ozy on
the Atlas in a box with slots in the back plate just big enough for the
connecters. Atlas bolted to box on metal spacers.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>2) Merc and Penny
coax cables in miniature Teflon microwave cable with 2 passes through
stack of 3 small ferrite torids (43 or 67 Material) close to backplane
entry</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>3) Mic and headphone
cable wrapped around ferrite toroid again at back plane entry. 1nF 1206
SMD across Electrect insert pins (cheap Skype headset)</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>4) Added missing
filter components on ATX SM PSU mains in and removed all unused connectors and
leads on Low voltage output. Added stacked beads on 12V 5V etc outputs and
parallel 10nF and 1nF to ground. Ran output to Atlas in shielded
cable.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>5) My install uses
my own design intermediate amps (2x2SC1969 to 2XMRF454) and LPF/HPF
driven by the Penny open collectors in a separate die cast. Relay supply is
filtered and relays decoupled by 10nF</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>6) All antennas run
on 600 ohm open wire with Gunella cross coupled baluns and about a
yard of coax into the shack. I added a choke balun at the tuner input on some
50mm ring cores (think they were Phillips 2C4 )</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>7) Do not attempt to
use PC powered speakers.They are impossible to RF proof. Best to strip the amp
out and place in a metal enclosure </SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>Hope this is of some
help.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=312322916-16032009></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=312322916-16032009>Shel
C1IZU</SPAN></FONT></DIV>
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