[hpsdr] Phoenix

[ad0es]

Helmut,

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1: Would this work attached to the input of the DC854D-E ADC board?

https://www.dxengineering.com/parts/dxe-z10046b-pm#overview

You can find the DC854D-E schematic on my website: https://ad0es.net/dfcADC/

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2: I have an elecraft AT1 step attenuator, switched steps of: 1dB - 1dB 
- 3dB - 6dB - 10dB - 20dB

https://elecraft.com/collections/at1-model/products/at1-step-attenuator-kit

Would this go between the preamp and DC854D-E?

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3: I believe the band pass of the DC854D-E is 1MHz - 70MHZ.  I am 
sampling @ 61.44MHz for Nyquist 30MHz/10 meters.

I think I can live with that for now?

Eventually I expect to build a complete replacement board, but am hoping 
the above 2 items will get me by till then?
Any suggestions for an alternate COTS preamp?  Something I can buy now 
for use during the real front end design cycle?

tia,
Steve AD0ES
ps: thanks for the help, I can code the snot off a gorilla, but I'm a 
complete analog nube...

On 4/15/23 9:46 AM, Helmut Oeller wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi Steve,
>
> You asked for  guidelines of a reliable frontend:
>
> 1. to lift the typical noise figure of the ADC around 40dB, at least
> for  f>10 MHz a preamp with 20 dB gain is necessary.
>
> 2. on the other hand ADC clipping must be prevented due to too much
> gain: 31dB step att like Hermes or 20 dB fix att like Mercury will help.
>
> 3. Antialiasing filtering is mandatory: LPF for 1. Nyquist. If the
> concept allows undersampling, seperate BPF filters with reasonable
> stopband attenuation are to provide.
>
> 73, DC6NY
>