[hpsdr] picoPSU Noise Test - well, I still think they're cute.

[Christopher T. Day]

Ahti, Phil_C, Phil_L, et al.,

True, it was the simplest possible test I could think of with what I had
on hand. It had the feature that if the PSU passed, it would probably be
good for our purposes, but the bug that if it failed, nothing very
certain was learned. I would have preferred the former.

There are no FCC stickers on the picoPSUs - there hardly is enough room.
There is nothing posted yet for picoPSU-60-WI, I would suspect because
it is so new, but there is the following posted for the picoPSU-120:
<
http://resources.mini-box.com/online/picoPSU-120/CE-FCC_statement.jpg
>

I admit to wondering if they still make copper screen to allow lots of
air flow, and figuring that if worse comes to worst, we don't need the
disk power cables so they could be amputated (Ooooh, ouch) and a ferrite
put on the Feeder Supply cable. 

Do people think it would be worth me sending the picoPSU-60-WI to Phil
Lanese for EMI testing? From Ahti's comments, I'm not sure if that would
tell us what we need to know or not.


	Chris - AE6VK


-----Original Message-----
From: Philip Covington [mailto:p.covington at gmail.com] 
Sent: Friday, June 09, 2006 6:11 AM
To: Ahti Aintila
Cc: Eric Ellison; Christopher T. Day; hpsdr at hpsdr.org
Subject: Re: [hpsdr] picoPSU Noise Test - well, I still think they're
cute.

On 6/9/06, Ahti Aintila <oh2rz.sdr at gmail.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Chris,
>
> Your 5-turn magnetic pick-up loop doesn't necessarily tell the whole
> truth. It may be worse or hopefully better.
>
> Actually, we are not so much interested in the near field internal
> magnetic noise. That is not usually going very far and can be
> protected by metal shield.  More serious are the conducted
> differential and common mode noise voltages and currents that may
> propagate along the cables and wires anywhere and even radiate like
> any other electromagnetic transmission.
>
> You will need good measurement setup to find the truth. However, the
> EMC /RFI standards are usually interested only in frequencies above
> 150 kHz. We use our sound cards at frequencies below that where the
> noise levels are not controlled by the standards.
>
> Good luck and 73,
> Ahti OH2RZ

Yes, please don't count these power supplies out yet.  I just would
not push them as the recommended power supply for the project.  When
we get some hardware to run, we can evaluate exactly how bad the
problem is and then make a better decision.

73 de Phil N8VB


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