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Re: DC voltage to AIDC-3731AA

Gene Marks wrote:

I am making a DC-DC converter for the subject downconverter to replace the
current wall wart connected to an inverter and hopefully provide a more
stable voltage supply to the downconverter.

Wayne replies:

About a year ago I was planning to build a DC to DC converter to power my
AIDC downconverter.  Then K5GNA suggested that I simply bypass the 12V
regulator.  I did that, and now I power the downconverter via a bias-tee
with my 13.8V power supply.  The downconverter seems happy, and it was a LOT
less trouble than building a DC to DC converter.  And it's so much simpler
that it is surely much more reliable.

Once you've bypassed the internal 12V regulator, you also have the option to
power the downconverter with the preamp power signal from your transceiver.
I do that with my portable AO40 setup, but I don't do that at home because
my "home" downconverter has a PTC thermistor (on the crystal) that draws too
much current when it's first switched on.

Even if you build a DC to DC converter, you probably won't see any
improvement in your downconverter's performance.  The voltage of your "wall
wart" is so much higher than the dropout voltage of the regulator that the
regulator output should be very stable.

Wayne Estes W9AE
Mundelein, IL, USA

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