#Image radio tuner portable#
#Image radio tuner code#

The rest is not really physics, but the difference between an analog and a digital radio comes in the circuits after this and basically an analog radio extracts a modulation from the intermediate frequency which is amplified and sent to the speakers or radio output. It is much easier to synthesize an exact mixing frequency to tune with than to change the resonance of the antenna circuit. It is in the mixer you tune the reception in a modern superheterodyne radio receiver. The antenna circuit should indeed have a resonance within the band of frequencies you are interested in but this wide-band signal is then mixed with an internally generated sinusodial signal in the radio in an analog component, this subtracts the frequencies and lets the rest of the radio operate on a much easily handled frequency band (called the intermediate frequency). All this without any battery! :)īut actually the antenna in a normal modern radio is not the component that 'dials in' the selected broadcast frequency. The output signal is an alternating voltage, and by rectifying it with a diode (called a 'crystal' then.) you could extract a signal modulated as a varying amplitude of the carrier wave. You didn't actually change the length of the antenna, but by changing the inductor (a coil) or capacitor connected to the antenna you tuned the resonance.

Sadly, due to the FM receiver band constraints, you can’t listen to Jupiter on this one.In the early days of radio, the resonance of the antenna in combination with its associated inductive and capacitive properties was indeed the item which 'dialed in' the frequency you wanted to listen to. As we can listen in the demo video, it can still output some seriously loud music sounds!

#Image radio tuner code#

The source code shows how it is possible to control the Si4703 FM tuner chip to suit your needs.Īs for ICs, not everything is new, still used the good old LM386 amp to drive the speaker, which is almost 35 years old by now. It has volume control, radio station seek, and four buttons that allows quick access to memorized stations. A small OLED display lets the user see audio volume, frequency, selected station and still has space left to show the current available battery voltage.

#Image radio tuner portable#

With an Arduino Nano as the brains and controller for an Si4703 breakout board, he builds a completely functional and portable FM radio. This little project by is a modern radio DIY tutorial. The challenges of the past resulted in the proven solutions of the present in which we build upon. Now we have things like the Si4703 FM tuner chip that can tune in FM radio in the 76–108 MHz range, comes with integrated AGC and AFC, controlled by I2C, as well as a bunch of other acronyms which seem to make the whole DIY radio-building process outdated. Back in the day, building a DIY radio was fun! We only had to get our hands at a germanium diode, make some coils, and with a resistor and long wire as an antenna maybe we could get some sound out of those old white earplugs.