[hpsdr] SMPS the wrong way to go

[FRANCIS CARCIA]

I found those little buck regulators running at 300 to 500 kHz. generate a fair amount of noise. fc

--- On Wed, 8/11/10, Ray Page <page.ray at gmail.com> wrote:


From: Ray Page <page.ray at gmail.com>
Subject: Re: [hpsdr] SMPS the wrong way to go
To: phil at pharman.org
Cc: "FRANCIS CARCIA" <carcia at sbcglobal.net>, hpsdr at lists.openhpsdr.org
Date: Wednesday, August 11, 2010, 1:11 PM


If the SMPS were just slapped down on the board, there would be problems. But as Kjell pointed out, the SMPS's connection to the rest of the circuitry is the key to a quiet solution. Follow Kjells advice and there will be no SMPS problems.

-Ray



On Tue, Aug 10, 2010 at 7:49 PM, Phil Harman <phil at pharman.org> wrote:


***** High Performance Software Defined Radio Discussion List *****

Hi Frank,

Normally I would agree with you. However, having tested the very high
frequency SMPSU that Kjell designed on one of the prototype Hermes PCBs I
can confirm that this is the way forward.

This not your usual SMPSU Toto....

73's Phil...VK6APH







> ***** High Performance Software Defined Radio Discussion List *****
>
> An SMPS on the same board with a -140 dBM noise floor RX will degrade the
> board.
> Why make more noise, just remote the regulator or do a better heat sink.
> Any spurs are too much. Frank



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