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<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>G’day<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>It has been interesting to read some of the comments
about potential cases for the HPSDR.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>One of the important things to consider is ultimately
whether you wish to make a stand-alone HPSDR that contains not only Ozy, Mercury
and Penelope boards mounted on the Atlas backplane but also items such as a
100W PA, Alex filter boards, a 12V fan to cool everything and, potentially, maybe
Gibraltar when it comes along.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>I wanted to do all of the latter, with the intention
of running the HPSDR from old-fashioned linear power supplies (one switch-mode
power supply in my Pentium IV pc is quite enough ‘switch-modeing’ for
me - more is not worth the potential RFI problems).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>As a result, I did a back-of-an envelope sketch of an
old-fashioned box/radio chassis 18cm high by 29.5cm wide by 30.5cm deep, with a
tray-type chassis fixed to the front panel on which the Atlas backplane plus
Mercury, Ozy and Penelope could be mounted on top (along with a 50 to 100W PA
board out of an old commercial HF radio) and the Alex Tx LPF/Rx HPF boards
could be mounted underneath. The various USB/DB9/DB25/BNC sockets protrude
through the back panel, so the back of the unit is a kind patch panel/external
connection panel.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>My friend Bob VK6CG turned my dodgy back-of-an-envelope
sketch into a clever and practical design, which Phil VK6APH and myself plan to
use in a series of articles next year on how to practically put together a
HPSDR in the RSGB’s RadCom magazine and that will hopefully find its way
into a book about practical SDR in the next year or so. The only problem
is finding time to actually do this…<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>This design currently exists in prototype form and
there are no drawings available (and, yes, no time to produce them either
;-) ). However, those old-timers who are used to building chassis
for valve or old fashioned transistor designs will know what sort of chassis I
am talking about – the kind of thing that can be turned out on a garage
work bench with a decent vice, drill and pop-riveter.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Hopefully this gives some would-be HPSDR case builders
food for thought. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Vy 73<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'>Steve, VK6VZ<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-AU style='font-size:
10.0pt;font-family:Arial'><o:p> </o:p></span></font></p>
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