[hpsdr] picoPSU Noise Test #2 - not just a pretty face?

[Ahti Aintila]

Chris,

Could you still do the following test:
1. Use Preamp gain "High" instead of "Low" and antenna connector
terminated 50 ohm.
2. Place Sound Blaster MP3+ far away from picoPSU and any power cables
and check the noise level.
3. Move SB MP3+ on top of picoPSU.
4. Any difference in noise levels?

73, Ahti OH2RZ


On 10/06/06, Christopher T. Day <CTDay at lbl.gov> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
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> After the formal TeamSpeak session today, I got into a discussion of my
> picoPSU noise test results with Larry (K2LT) and Duffy(?). The result
> probably will be that I send one of the supplies to Larry for him to test
> with his spectrum analyzer, etc.; he tests such things for broadcasters
> professionally, but the 60W version only arrived Wednesday and I want to
> savor it a bit longer. Meanwhile, he suggested an alternative test.
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> I'm using a SoundBlaster MP3+ for my SDR-1000 sound card. This is only a
> 16-bit box, but it is USB and external to my laptop. Larry suggested that I
> put it, as a better representative of Janus, near the picoPSU and see what
> happens. So, I put my SDR-1000 back on 160m, terminated the input coax with
> a 50ohm dummy load to remove sky noise and set the MP3+ on top of the
> picoPSU-60-WI. See photo at:
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> http://www.hamsdr.com/personaldirectory.aspx?id=318
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> The result is in the RTF (WordPad) file at:
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> http://www.hamsdr.com/personaldirectory.aspx?id=319
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> This time, I see no effect at all turning On the Feeder Supply and picoPSU,
> albeit there is no load yet on the supply!
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> The MP3+ is a quite inexpensive box. From its weight, I would say its case
> is strictly plastic; once I get the nerve to void the warranty and open it
> up, I will check for internal shielding, but I'm betting it's minimal at
> best.
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> Whew, that makes me feel a little better, at least until morning. Comments?
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>             Chris – AE6VK
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