Izbornik Zatvoriti

Kategorija: Radio-amaterizam

Upotrebljavate li SWR-metar?

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Skraćena veza: https://pedja.supurovic.net/veza/9846

Neophodno je da antena koja se povezuje na predajnik ima impedansu koja odgovara impedansi predajnika. Ako ove impedanse nisu usklađene, u antenskom sistemu se javlja reflektovana snaga. Ova snaga se sabira sa emotovanom snagom i javljaju se vrhovi snage koji mogu biti značajno veliki i izazvati i kvar radio-stanice. Takođe, usled neusklađenosti impedanse velika je verovatnoća da će izračena snaga u antenu biti znatno manja do zanemarljiva. Takođe se povećavaju neželjene smetnje koje antenski sistem emituje u okolini radio-stanice.

Neusklađenost impedansi antenskog sistema i predajnike je uvek loša stvar i mora da se izbegne. Da bismo to izbegli moramo prvo da izmerimo. […]
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Fast hand writing for receiving Morse code

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Skraćena veza: https://pedja.supurovic.net/veza/9817

Receiving Morse code is a challenge. It is achievable and there are operators that reached stunning skills of receiving Morse Code in very high speeds. One of the limitations is hand writing speed, thus most high skilled operators receive Morse Code „in head“. But sometimes you do have to write it down, right?

First helping technique that should and is learned along with learning Morse Code itself is optimal hand writing. This cuts number of strokes for each character which speeds up writing. Also it is important where strokes end to minimize movement between written characters.

This image shows one of the ways to optimize hand writing. […]
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Radio-amateri od RATEL-a dobijaju pretnje izvršiteljima

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Skraćena veza: https://pedja.supurovic.net/veza/9797

U drugoj polovini 2019. godine radio-amateri su od RATEL-a dobili obaveštenje da je RATEL doneo odluku da promeni iznos naknade za korišćenje radio-frekvencija za radio-amatere. Iznos je sa dotadašnjih 10 dinara podignut na 1000 dinara. Da,  dobro ste pročitali – uvećanje od samo 100 puta!

Ovim su radio-amateri dobili izuzetnu zahvalnicu za sav svoj rad na tehničkom obrazovanju mladih i sve svoje humane aktivnosti u vanrednim situacijama.

Naročito je interesantno da je RATEL obavestio da je ovu promenu uveo retoraktivno za 2018. godinu.

Obaveštenje je sadržavalo poziv radio-amaterima da se izjasne da li se slažu sa ovom odlukom a nisu ga ni dobili svi radio-amateri. […]
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Fixing Baofeng UV-B5 broken battery latch using 3D printer

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Skraćena veza: https://pedja.supurovic.net/veza/9740

I’ve got UV-B5 years ago. It survived lots of use and still served fine. There was one glitch – in some moment latch that keeps battery locked was broken. Radio was still usable but it happens from time to time that battery slips out of socket and radio silently turns off. It was quite annoying but hardly fixable issue.

Until today.

As I recently got myself 3D printer (Prusa I3 MK3S) I get to an idea to model and print replacement part. As every experienced computer expert, I first looked if someone else already did that. And indeed, Thingverse member Olex had the same issue and already did modeling. […]
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Universal CAT and programming USB to serial TTL interface for ham radio

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Skraćena veza: https://pedja.supurovic.net/veza/9536

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. […]
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