[hpsdr] Atlas Power Supply

[Sattler, Jay]

After lurking on the list for a few weeks, finally a topic I can help
shed some light on.  While working for HP, I had the task of qualifying
ATX power supplies for Industrial computer products.  If I recall
correctly, the ATX Power Supply Specification defines Output
Ripple/Noise requirements only for 10Hz-20MHz.  For that range it's
50mVp-p on the 3.3 and 5 V rails and 120mVp-p on the 12V rails.  Outside
of that range, it's governed by the appropriate FCC emission
requirements.  My testing showed lot of low cost computer power supplies
had some pretty ugly spurious emissions in the HF band.  Myself, I think
I'll build up a nice clean linear power supply for my Atlas.  Any ideas
on the current draw requirements for each of the rails?   

-----Original Message-----
From: hpsdr-bounces at hpsdr.org [mailto:hpsdr-bounces at hpsdr.org] On Behalf
Of Christopher T. Day
Sent: Thursday, November 30, 2006 11:13 PM
To: John Koster; Philip Covington
Cc: hpsdr at hpsdr.org
Subject: Re: [hpsdr] Atlas Power Supply


***** High Performance Software Defined Radio Discussion List *****

I've been using the following switcher supply.

http://www.mini-box.com/picoPSU-60-WI?sc=8&category=13

I am not in a position to say this is an acceptable alternative, just
what I have. I don't have anything to compare it with. There are
certainly some odd artifacts that I see in the panadaptor display, but I
don't know for certain if they are from the microPSU or the +-15V supply
in the SDR-1000 for the instrument amp or something from my rather high
RF environment. (I live at the foot of the primary radio-TV transmitting
tower for the San Francisco Bay Area.)

In terms of filters, it sounds like a good idea. There were some
references earlier in this mailing list to a technique for finessing the
noise from a switcher that looked interesting if someone wanted to
follow it up.


	Chris - AE6VK



-----Original Message-----
From: John Koster [mailto:w9ddd at tapr.org] 
Sent: Thursday, November 30, 2006 9:14 AM
To: Philip Covington
Cc: hpsdr at hpsdr.org
Subject: Re: [hpsdr] Atlas Power Supply

***** High Performance Software Defined Radio Discussion List *****


On Thu, 30 Nov 2006, Philip Covington wrote:

> ***** High Performance Software Defined Radio Discussion List *****
> 
> On 11/29/06, Bruce K3CMZ <k3cmz at arrl.net> wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > Has a power supply source been found
> > for the Atlas / HpSDR project?
> >
> > I think it is time for me to start getting
> > ready!
> >
> > Bruce K3CMZ
> 
> We need to do some testing with the JANUS board and PC power supplies 
> to see how they might affect the excellent performance of the JANUS 
> board.  I think at this point everyone has been powering the JANUS 
> from linear lab bench supplies.
> 
> Phil N8VB

This may suggest another project.  A filter block that goes in-line 
between the PC PSU and the Atlas back plane. 

-- 
73,
John, W9DDD

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