[Laser] Mystery Modulated Light

[Chuck Hast]

For those of us who reside in the Linux/Mac/Unix world there is
Baudline:

http://www.baudline.com/download.html

I have used this tool to dig out all kinds of offending signals.
Put it on a older laptop and it makes a great tool to do all
kinds audio subaudo and as high as your sound card can
process.


On Sat, Jun 30, 2012 at 7:23 PM, MICHAEL COUTURE
<mikecouture at bellsouth.net> wrote:
> Hi Steve & Group,
>
> I don't know if it has been suggested before but there is a FREE audio spectrum program that will look at signals in the dirt all the way up to kHz range. Here's the url:
> http://www.weaksignals.com/
>
> It's called Spectran and works GREAT. Just download and install it. Hope that helps.
>
> Mike C.
>
> --- On Sat, 6/30/12, steve kavanagh <skavanagh73 at yahoo.ca> wrote:
>
> From: steve kavanagh <skavanagh73 at yahoo.ca>
> Subject: [Laser] Mystery Modulated Light
> To: laser at mailman.qth.net
> Date: Saturday, June 30, 2012, 6:14 PM
>
> There's not a whole lot to record....it sounds just like a constant frequency tone.  My receiver has significant rolloff above 2 kHz, so the harmonics I hear are probably at lower levels than in the raw signal.  But it might be worth taking a look with an oscilloscope at the receiver output instead of a spectrum analyzer, to see what the waveform is like (duty cycle of pulse, or is it a triangle wave, etc.).
>
> I agree with Stuart that most of the LED drivers I have seen data sheets for operate above 30 kHz.  I did see one that was FM-ed at a 1 kHz rate to minimize EMC spectral density problems.
>
> Maybe there is someone running a beacon with no ID !
>
> 73,
> Steve VE3SMA
>
>
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-- 

Chuck Hast  -- KP4DJT --
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."
---
Home web site:
www.wchast.com

ZoneMinder Demo and test site
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