From: Jim Choate <ravage@ssz.com>
Date: Sun, 3 Mar 1996 13:19:41 +0800
To: cypherpunks@toad.com
Subject: Re: RNG method (fwd)
Message-ID: <199603030529.XAA03142@einstein.ssz.com>
MIME-Version: 1.0
Content-Type: text



Forwarded message:

> Date: Sat, 2 Mar 1996 23:24:04 -0500
> Subject: Re: RNG method
> > 
> >  - Use a microphone on your sound card and locate it close to the
> > computer fan.
> 
> It's been thought of before, along with scraping the microphone against
> the desk.  I've been told this works best when first turning the gain up
> on the soundcard and setting it for stereo input.
> 

If you use the fan remember in your power supply remember that many of them
run directly off the 120 VAC. As a consequence the sound it makes will have
a strong 60Hz componant.

If you are using a DC bearing fan then there will be a componant in the
noise related to the number of balls in the bearing.

DC bearingless fans should provide the best white noise provided the
bushings are not worn. Once they wear you will be a harmonic related to
shaft diameter, shaft length, and the gap between main shaft and bushing.