21 January 2008

LED ERP vs. current

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While searching for optical RX-TX systems that would carry voice, I stumbled across an article of the only Italian HAM (AFAIK) that has docu...
18 January 2008

HP iPAQ h5450 dead/flat battery

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So, you forgot to recharge your iPAQ h5400 PPC handheld for a week and it doesn't power up anymore? Not even if you leave it plugged to...
07 January 2008

MCW optical TX - first test

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Finally, more than a year after the idea of an optical RX-TX system was born, I have been able to send (pseudo)information through modulated...
24 December 2007

The Joule Thief

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I had it ready for months, but never finalized. This Xmas 2007 we needed a simple way to light the Nativity scene, so I took the chance to g...
11 December 2007

Driving a LED from TTL/CMOS

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It's the first thing you learn about TTL/CMOS chips: they cannot ( should not ) drive a LED directly. A transistor driver is needed, and...
13 November 2007

CCD as infrared sensors

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This might be obvious to many of you, but it wasn't to me. CCD , the digital camera sensor, is sensitive to infrared light, such as the ...
12 November 2007

Antenne Yagi per usi portatili - Q&A

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Data la visibilita' che ha questo blog tramite alcuni motori di ricerca (e' una semplice constatazione), postero' qui in forma a...
29 October 2007

Multiband beam (70 MHz)

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I have no experience on this matter, so this is a purely theoretical post . If looking for a directional antenna that covers 50 MHz, 70 MHz ...