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

[Eric Ellison]

Phil

I couldn't agree more. Don't countem out but don't recommend them. There are
a lot of really neat things going for these units, it behooves us (IMHO) to
at least attempt to identify the weaknesses and see if we can overcome them.
Really that is what this group is all about. Just because this was not an in
house "HPSDR - Design" doesn't mean we can work a little at solving the
problem, or making good choices.

I was thinking today, just from the shape and size of the unit, that, some
tin snips and some copper flashing from the local hardware, might solve the
problem, with a PicoEnclosure. I don't think they generate too much heat
(advertising).

As Ahti says, it might just be near field radiated noise. Someone just needs
to come up with some 'copper based orgami' to test.

One thing it does say as Bill alerted, "We gotta qualify everything" and not
rush to judgement.

Just my 2 cents.

Eric
 

-----Original Message-----
From: Philip Covington [mailto:p.covington at gmail.com] 
Sent: Friday, June 09, 2006 9:11 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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