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 ...
22 October 2007

Antenna tuners are reversible

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I'm back on posting after a few weeks without any shack or lab activity. I had few minutes to spare, so I wanted to do a measurement on ...
28 September 2007

Closed for holidays

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About to take a short vacation, with lots of open projects: FT-817 hands free adapter Finishing 4m TX #1 Rebuilding 4m TX #2 (it has a short...
25 September 2007

Controlling canned oscillators

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For a number of projects it might be interesting to control the frequency of a canned oscillator. Some of them have a control pin, others an...