µBITx

The µBITx, pronounced Micro -Bit -X  is an amatuer radio transceiver.  It works from 3 – 30 Megahertz.  It is a kit, sort of, and is very inexpensive.  Mine was $109 with a $10 dollar extra charge for REALLY fast shipping from India. It was accepted for shipment 65 hours before delivery in South Texas.

There are many cool things about this radio. 3- 30 Megahertz is a very big swath of radio frequency. It sends and receives morse code and single side band voice. AM radio waves are made by combining a radio frequency signal, a plain sin wave at a fixed frequency with an audio wave. What comes out of the radio is the fixed frequency wave called the carrier and two side bands that are the carrier plus and minus the frequency of the audio. The carrier , although it is called a carrier carries no information other than what the fixed frequency is. The two side bands duplicate the audio information. What single side band does is eliminate the carrier and one of the side bands early in the process and amplifies the remaining sideband. Having to only amplify one part of the signal allows it, using the same amount of power, to be stronger. All of the juice goes into the one side band making it louder, stronger.  It also creates a much less wide signal allowing more conversations to go on at the same time. Please do not consider me an expert on any of this. My knowlege is really limited and people with more abound.

So, how does this radio work?  Old radios produced the carrier with a combination of components. The easiest way  to make an oscillator is with a coil and a capacitor. The coil holds a charge in magnetic field, and a capacitor holds one in an electric field. These two devices when set up properly send energy back and forth between each other at a certain frequency determined by how they are constucted, how “big” they are. The problem with these simple oscillators is that they change frequency with temperature, and the heat up with use.
Skipping all of the other intermediate steps in oscillator development, at least in part because I really know little about all of this brings us to the µBITx.

The µBITx creates its base frequency with chip that has a circuit designed to create the frequency of your choice. You program in what you want and the frequency comes out. The chip accepts commands using a language called I2C. THis language goes over a pair of wires.  The computer that sends this is a small computer I am a bit familiar with called an Arduino.