[Laser] White color LEDs

[Charles Pooley]

White cannot be modulated at a high frequency--the phosphor is slow.  Also it is 
of a larger area than the blue driver chip (which acts like a typical LED).

Red is usually best if the detector is silicon, or blue or near UV is the 
detector is PM tube.

Lasers, either red 650 nm or blue 405 nm are far better, because a narrow 
interference filter can be used for cutting out background illumination.
With optics the beam can be of any width you want, from arc seconds to degrees.





________________________________
From: "Zilvinas, AUGMA" <zilvinas at augma.lt>
To: laser at mailman.qth.net
Sent: Thu, October 21, 2010 4:08:48 AM
Subject: [Laser] White color LEDs

Hi all,

There are many cheap powerful white LEDs available (f.e. dealextreme.com)
Are there any _significant_ disadvantages using white color instead red 
in our applications (voice comms)?

Thanks and best 73!
Zilvinas LY2SS
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