[hpsdr] Power Supply test

[stoskopf at tri.net]

Deciding that to plant a $5 tree, you should dig a $10 hole, I ran thru
some computer magazine reviews of ATX supplies and settled on the
Turbo-Cool 510 ATX for the $200 range.  Also ordered the 1 Amp load
resistor recommended.

Arrived today.  Excellent temperature controlled fan..quiet.

Rated 0.05% P-P ripple.

A brief test with only the load and the Bitscope 310 revealed about 60 mV
p-p spike/switching noise.  The fft of the noise was flat from DC to about
2 MHz and smooth roll-off to 2.5 MHz.  This on the +12V line and is right
at the spec.  I need to play a bit with loading, but I'm not really
interested in putting this much noise in the box with a microvolt front
end.

Not a critique of PC Power and Cooling as it is well built, but maybe just
typical of a switcher.

N0UU