[hpsdr] picoPSU Noise Test

[Achim Vollhardt]

I have to support Bob's comment. A PSU unit compatible with low EM
radiation is built in a complete different design than this picoPSU,
although I have to admit they LOOK nice.. just not for HF work.

Shielding is only half the way.. ALL in- and outputs need heavy
capacitive decoupling AND inductances. And by the time you are done with
it, it may have been better to design a plain linear power supply from
scratch. Power effectiveness is nice, but admittedly not the point with
HPSDR but HF performance.

Is the following the specs for the HPSDR?

5V 6A 10A 1.5%
5VStand By 1.5A 2A 1.5%
3.3V 6A 8A 1.5%
-12V 50mA 50mA 5%
12V 400mA 450mA 3%

(took it from a picoPSU post earlier)

If yes, I would vote for a straight linear approach. Don't get me wrong,
I am much in favour of switched PSUs and have designed some for up to
400W with >90% eff, but the price you pay in terms of EM radiation is
high. And and 80 W (approx.) linear PSU is certainly less work.

73s Achim, DH2VA

ps: I also would not bother about trying a standard ATX PSU.. same
problem, perhaps not as pronounced.


> Date: Fri, 09 Jun 2006 08:34:41 -0400
> From: Robert McGwier <rwmcgwier at comcast.net>
> Subject: Re: [hpsdr] picoPSU Noise Test - well, I still think they're
> 	cute.
> To: hpsdr at hpsdr.org
> Message-ID: <44896AE1.9020906 at comcast.net>
> Content-Type: text/plain; charset=windows-1252; format=flowed
> 
> WOW. That is nasty. For my part, I will be using my Shenzen Mastech 
> bench supplies until I find one that is quieter than church mouse.
> 
> No, there is no point. That P.S. effectiveness for our project is right 
> up there next to a screen door in a submarine. You really might have 
> predicted this. From the pictures we have been seeing, EMI/RFI is not a 
> consideration. There is insufficient filtering just from the component 
> sizes and essentially no shielding whatsoever.
> 
> Bob