26 June 2014

Rebuilding a dual-band mobile antenna

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Until few months ago in the car I used one of those ultralight dual-band magmount antennas. They come with such a long RG174 coax that all t...
21 June 2014

Newly built memory keyer (based on K3NG work)

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This is the 400th post on this blog! O ne year and half after discovering my old memory keyer had been dipped in battery chemicals , I fin...
18 June 2014

Talking AT commands to GSM cell/smartphone (over Bluetooth)

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Today's discovery, by chance, was that some cellphones/smartphones expose a "standard old fashioned" serial modem when connect...
03 May 2014

First time in Japan

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This morning on 12 m I got my first reply from JA. OM JF2IWW was 539 with deep QSB, but he copied my 5 W and gave me a 439. Then fading took...
02 May 2014

How cellphones vibrates

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V ibration alert in mobile phones is accomplished with a small but powerful electric motor that spins a small asymmetrical weight. In the pi...
15 April 2014

Not much gong on (on 10 metres)

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As usual, Spring decreases my will to build circuits (that's why there were no updates for a while). But I feel the urge to radiate some...
24 February 2014

AD9850 board and temperature

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My AD9850 DDS chip and the 125 MHz canned oscillator run pretty warm to the touch. No info were found online, so here you are my values in r...
18 February 2014

Arduino controlled AD9850 DDS signal generator

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Been blog-silent for a while, but my AD9850 DDS is now complete. The Arduino (Nano) code evolved day-by-day while assembling the circuit. I ...