[hpsdr] Analog Vs. Switching power supply for OZY Janus...

[Al]

Henry,
   I have rerun the comparison with SDR-1000 cabled up and connected to 
a 50 ohm load and I can see only a minor difference with the preamp set 
at high. See attached screen shots.

  I am not saying that analog or switching supplies are the right or 
wrong answer for OZY/Janus/SDR-1000,
just that not all switchers are automatically bad.  ( I have seen some 
lab switchers made by well known names that had noise problems. )

The SDR1000 runs on an analog supply.

AL, K0VM



Henry Vredegoor wrote:
> Hi Al, All,
>
> Did you also do a comparison WITH the audio cables connected and a 50 Ohm
> termination at the antenna input?
> Would like to hear/see the results.
>
> 73's,
>
> Henry.
>
>
>   
>> -----Original Message-----
>> From: hpsdr-bounces at hpsdr.org 
>> [mailto:hpsdr-bounces at hpsdr.org] On Behalf Of Al
>> Sent: maandag 11 juni 2007 1:19
>> To: hpsdr at hpsdr.org
>> Subject: [hpsdr] Analog Vs. Switching power supply for OZY Janus...
>>
>>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> I have been running Ozy/Janus with the SDR-1000 and noted the 
>> discussion 
>> of spurious signals when connected to a PC supply..   I would like to 
>> offer that all PC supplies are not created equal. I recently 
>> completed a 
>> comparison test of PC supply vs. analog bench supply and see no 
>> significant difference in the resulting noise floor, number 
>> of spikes or 
>> their amplitude.
>>  Test Conditions.
>>       Janus modified with 1K gain reduction resistors installed ( per 
>> KX2O suggestion). Sample rate = 192 Khz.  All analog cables 
>> disconnected 
>> from Janus.  Parallel control cable connected to SDR-1000. USB cable 
>> connected to computer.
>> PC Supply was a CODEGEN 200X1 (300 watts).
>> Bench supply was a Heathkit IP2718.
>>    
>> Screen shots available on request..
>>
>> AL, K0VM
>>
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>>     
>
>
>   

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