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M0KGK SDR soundcards page, last updated 2006-12-08
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This is the soundcards page for KGKSDR.  It contains info on soundcards that have been tried with KGKSDR, and some notes and measurements around each one.

Noise performance

Some soundcards (notably onboard ones) are fine if you want to have a look at SDR, but are not that great for serious use.  For DX use, a quality 24 bit soundcard running at 96kHz is recommended and this will mean spending some money.

16 bit cards will work, but the lower resolution and noise performance makes them less than ideal in the DX stakes, especially on the higher bands where noise is much lower.  The following is a chart showing the noise performance of three soundcards:


Chart of soundcard noise performance - click on the pic for larger version

The chart shows four traces, two have been provided for the Soundblaster Live! 24 and are marked (A) and (B).  (A) is where the line in has been set to the maximum value and (B) is where it has been set to approximately half way.

The measurements were carried out by leaving the input unplugged on each soundcard and recording the resulting amplifier/ADC noise.  A 32768 point Fast Fourier Transform with a Hann window was used on the cards (16384 in the case of the lower samplerate AC97), and the results from the frequency domain averaged out over a 5 minute period.

M-Audio's Delta 66 shows the cleanest spectrum, the near-identical Delta 44 card costs 99 in the UK - about ($175 at Jan 06), the Soundblaster Live! 24 turns in a creditable performance and only set me back 12.50 (approx $22).  The onboard AC97 soundcard is OK for having a look at SDR but cannot be recommended for any kind of serious use.

 

These pages and contents are Copyright 2004-2014 Duncan Munro M0KGK.  All trademarks used herein are acknowledged.  Email any queries about these pages to postmaster@duncanamps.com