Any beginner can build this from components that can be found in an electronics scrap heap or are at least inexpensive. Yet, this device is both an interesting demonstration piece and a practical tool because it relies on cool physical principles to provide a useful function. When used with a radio receiver, it can determine…
After you finish reading this article, please also read the sequel: This real-time Morse decoder uses the Goertzel algorithm to detect a CW tone of 708 Hz. In order to better isolate the useful signal, the program introduces comparing the magnitudes for three frequency bins – the central one and two adjacent ones on both…
This shield was designed with no particular project in mind. It aims to be useful for both automatic and keypad-operated antenna selectors in general. This is just hardware, providing slightly more than a set of ten relay drivers, but there are many projects/sketches on the Internet (including this blog) that could be easily adapted to…
Gradio sam razne birače antena. Oni se po pravilu sastoje od dva dela – upravljačke i preklopne kutije, koje su povezane upravljačkim kablom. Zadnjih nekoliko godina ustalio se jedan model preklopne kutije, tj. kutije s relejima. Ona je za pet antena i predstavlja kompromis: bilo bi lepo da predviđa više antena, ali je i pet…
The JRL21 Noise Reduction Module removes fan noise much better than expected. (Or perhaps my expectations were too low.) You can listen to two ‘before/after/before‘ audio examples. See links at the end of the article. Prostorija oko radio-uređaja ume biti vrlo bučna, posebno ako su tu veliki pojačavači snage i njihovi ventilatori. Može biti poželjno…
NanoVNA jeste open-source vektorski mrežni analizator – sprava za merenje radnih parametara antena i svega drugog u šta ulaze i kroz šta prolaze signali visokih frekvencija. Minijaturan je i relativno jeftin, dostupan prosečnom radio-amateru koji sam petlja oko antena, filtera, pojačavača. Pomoću NanoVNA može se meriti i analizirati impedansa, odnos stojećih talasa (SWR), meriti frekvencija…
If you follow groups or forums where hams ask for help with equipment issues, you may have noticed that transmitters show a pronounced tendency to fail while they are being used for digital (data) modes. It seems that people often forget that amateur transceivers are not designed to transmit at full power for longer periods…
The FTDI drivers are easily available and often already present in the OS. The interface will present itself to the user as a new COM port. In Device Manager go to this new COM port Properties->Port Settings->Advanced. Then in the Miscellaneous Options section (bottom right) uncheck Serial Enumerator and check Disable Modem Ctrl at Startup.…
Radio-amateri mogu voditi duge razgovore o mikrofonima i SSB modulaciji, kao ovde:https://www.eham.net/article/8069 Iskustvo sa kratkih talasa: ako se sve ostalo podesi kako treba, elektretska (“kondenzatorska”) kapsula od 50 dinara može zvučati odlično. To je ona, na primer, sa slušalica s mikrofonom za PC ili: https://www.mgelectronic.rs/mikrofonska-kapsula U prolazu kroz SSB predajnik i prijemnik, audio-signalu ograničeni su…