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Oznaka: ham radio

Obavezno koristite SWR-metar

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Kad god me pitaju za savet oko nabavke radio-stanica ne propustim da napomenem da uvek treba imati SWR-metar.

Ne mora biti neki skup, fensi i precizan – bilo kakav je dobar samo ako je ispravan i radi na opsegu na kome vam je potreban. Često za 2m može lepo da odradi posao i neki od onih superjeftinih CB SWR-metara, samo ga prvo isprobajte.

Ako ne možete da kupite – napravite.

Večeras posle dužeg vremena uključim UKT stanicu i na prvo emitovanje vidim da je SWR beskonačan. I pored toga, prolazio sam kroz repetitor sasvim normalno. Da ne bi instrumenta, ja bih stanicu koristio nesvestan problema. […]
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Custom Morse Code for Mobile Phone Ring Tone

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Wouldn’t it be awesome to have Morse Code playing instead of plain ringtone on your phone? You would know who calls without need to reach phone. Of course it would require you to have skill of recognizing Morse Code, but that is minor issue, right? If you do not know it yet, it can be learned. It’s great skill to have, anyways.

Well, there is simple tool that may help: Morse Code Generator . It creates audio file with sound of Morse Code using your custom text. Generated sound is nice sinusoidal tone, pleasant for ears.

What you do is type in text phrase, choose Morse Code speed and Tone frequency and click button Generate. […]
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Dipole Antenna Center Insulator for SO239

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Building dipole antennas is always some kind of improvisation. Center insulator is quite simple and may be made in short time with jigsaw and drill.

As I jumped in CNC world I need some simple tasks to learn how to use FreeCAD and other software. So, dipole center piece is ideal just for that. I’ve finished project and learned a lot in the process.

Finished projects is uploaded to Thingverse: https://www.thingiverse.com/thing:4149187

You may use CNC mill or 3D printer to make this part. Pay attention to use material strong enough to survive possible strong forces. […]
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Universal CAT and programming USB to serial TTL interface for ham radio

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Some years ago I posted article describing Universal CAT and programming USB to RS232 TTL interface for ham radio that I made.

Here is small update, adapter for YAESU FT-8900, FT-8800 and alike radios.

FT-8900 and FT-8800 and some other Yaesu radios use two wire interface. One wire is ground and other is both RX and TX. This is also known as CIV-I interface used in Icom radios.

CIV-I interface is quite simple. There is a diode (universal like 1N14148) connecting RX and TX, oriented cathode toward TX, with one 10K pull up resistor to 5V on RX. Here is schematics:

However, I found out that YAESU FT-8900 already provides pull up voltage on PKS line, so, there is no need for 10K pull up resistor. […]
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Vežbajte otpremanje Morzeove telegrafije samo sa ručicom i računarom

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Za usavršavanje tehnike otpremanja Morzeove telegrafije potrebno je odvojiti dosta vremena za vežbanje. Zgodno je ako to možete da radite kad god imate vremena.

Za to su vam potrebni ručni taster ili ručica i tonski generator. Taster i ručica se nabave (svaki radio-amater valjda to već ima) a kao tonski generator se obično koristi radio-stanica ili, ko se bavi elektronikom, može i da napravi.

Međutim, ako imate računar, on može takođe da završi posao. Postoji nekoliko programa koji rade kao tonski generatori a taster i ručicu na računar povezujete preko serijskog priključka na računaru.

MorseKeyer je jedan od takvih programa. On služi kao klasični ton generator za Morzeovu telegrafiju. […]
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