Beacon UHF IQ5IN/B

 

Scritto da Marco IU5HKU

Il cuore del beacon è il chip RTX Si4463 prodotto dalla Silicon Labs, programmabile in frequenza senza soluzione di continuità da 114Mhz fino ad 1GHz circa, con una potenza configurabile in 128 step da 0 a 100mW.

A bordo del piccolo modulo trova posto un vcxo con freq.di lavoro 26MHz e la componentistica per il funzionamento del chip e l’adattamento di antenna, la comunicazione col chip avviene tramite linea seriale MISO/MOSI a livello logico 3.3V per cui si rende necessario mettere come minimo delle resistenze di adattamento se si intende farlo lavorare con la famiglia degli arduino 5V (o altri processori embedded simili).
La caratteristica interessante del Si4463 è quella di avere un pin per la modulazione diretta della portante, a scelta tra i 4 general purpose I/O di cui dispone, il tutto è programmabile sfruttando le api che silicon labs mette a disposizione nel datasheet di libera consultazione.
Nel nostro caso tale pin è stato collegato ad un’uscita digitale di arduino per il keying on/off della modalità CW che il chip offre in maniera nativa insieme alla 2(G)FSK e 4(G)FSK e la potenza è stata impostata per il massimo possibile, 100mW.
La parte di temporizzazione della trasmissione e della corretta durata del tono morse è gestita completamente da arduino, che fornisce anche l’alimentazione necessaria a 3.3V, che visto l’esiguo assorbimento di circa 80mA del modulo stesso può essere prelevata direttamente dall’apposito pin di arduino (prelievo massimo ammesso circa 200mA).

Qui di seguito l’articolo completo pubblicato sul mio account di QRZ.com:

This is our CW Beacon, IQ5IN/B, or better say this is the first part, we still waiting for a power amplifier we bought some times ago. Anyway, the entire project is easy to assemble and work for sure at the first try, only five resistors to adapt the communication logical level from 5V to 3.3V, GND and 3.3VCC and you are ready to go. I’ve used an already made source code, only slightly mods were necessaries to adapt the entire things to our purposes, but there is plenty of room for improvments, the Si4463 can work in OOK (on off keying) 2FSK and 4FSK, you can do a lot of interesting things with this module, aprs is the first thing who came in my mind. Some useful links:

Github repository by RA9YER (tu so much Alexander, great piece of code)

https://github.com/alexander-sholohov

Datasheet of the Si446x Transceiver (yes, you can transmit AND receive)

https://www.silabs.com/documents/public/data-sheets/Si4464-63-61-60.pdf

Our beacon, IQ5IN/B was heard this evening in Sicily by Vincenzo IT9TVF a dear friend of mine. He was my first dx contact in my first attempt to have a qso on 2m in SSB and we still have contacts from time to time. His QTH is Carini, 589,5Km far away from here, Sicily, he’s an experienced OM and still mantain the ham spirit as in the beginning of his radio career, great man indeed. In Carini there is a great community of ham radio enthusiast, very active not only in radio, but also in many social activities, you can visit the website of IQ9IL, the Carini hamradio club, and have a look at the beautiful seascape they have, there is also a webcam in the page.

Great part of this little record is in the Vincenzo’s 23 elements UHF Yagi, he’s also a great homebrewer too. Some photos of this great result:

Sorry for the poor quality, as always my smartphone need to be replaced to a better one….in the first you can see the magnificent IQ5IN/B in test from my terrace, in the box take place an arduino and a Si4463, as you can see in the photo in my last post, only ten cm of wire and the signal goes straight into a big wheel antenna, there is nothing more. In the second the distance covered by this little piece of hardware, mainly through open sea (i have a little hill just in front of my terrace who remain in the trajectory unluckly).

 

And this is the transceiver used for the reception, note a slightly shift in frequency that need to be investigated….but hey…only a bunch of mW, and you know how difficult his to be heard in UHF…

Vincenzo was so kind to give us a small video about the reception, you can see the video on his youtube channel at
this link: Vincenzo IT9TVF hearing IQ5IN/B

Thank you so much Vincenzo, best 73 from Tuscany!!

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