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

[Ahti Aintila]

Chris,

I think that Phil_C's suggestion is the most pragmatic choice. After
that Phil_L's "secondary standard 3M/10M EMI lab" would tell what is
the problem and how to solve it.

Of course, if Phil_L has time for the measurements, he obviously with
his experience can already now simulate the actual situation the best
way and suggest necessary filtering and shielding arrangements.

73, Ahti OH2RZ


On 09/06/06, Christopher T. Day <CTDay at lbl.gov> wrote:
> 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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