Simple AM Radio receiver for emergency situations

Radio receivers are very simple and amazing. They can be very helpful in times of need. We already have a post about creating a simple DIY AM transmitter. We know that our society is obsessed with new time technology like social media, gadgets, smartphones etc. All these new media are based on internet and data. If anything happens to cell phone, internet or telecom sector our communications can be affected. We all know how much important communication is. So we are making a simple AM radio receiver to help us in time of emergency.

There may be a time where there is no means of communication. We may be in some disaster. In such a situation, we may need to make DIY tools for communication. The best thing we can do is use an AM transmitter and receiver. This is a good backup plan and fun project as well. If you have a readymade one for an emergency that is good. Else if you do not have this, it is very simple to make.

We already have AM transmitter making steps in our older articles. In this article, we just show steps of making the receiver. The receiver end takes the transmitted signal and then gives output in sound which can be heard by us. It can be used for an emergency and it can be a fun project to play with your children. Children can also build this as their science project.

Preparation for build

Finding things we need is very easy. Below listed items are easily available in the local electronic parts store. People in the USA  can find in RadioShack. Other people can also try their local stores and online sites. These are the things we need to make our simple AM radio receiver.

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1) Antenna (Copper Wires/Metallic rod)
2) Tuner (Copper Coil and Capacitor)
3) Germanium Diode
4) Connecting wires
5) Speaker
6) 150K Ohm Resistor

We bought everything from local stores near us. We are based in Kathmandu and such parts are available in Bandemudha.  There is a market in Bangemudha on the way to Nara Devi from Ason’s Annapurna Chowk. After collecting all the parts lets start building our DIY AM receiver or radio. This is actually a crystal radio and it is one of the simplest forms. Just follow the schematic diagram given above in this post.

Explanation

First of all, for the radio, the antenna is most important. We are making this using insulation less copper wire or iron rod of any length (longer the better). End of the antenna goes to wire that connects the copper coil. The coils other ends have capacitors in parallel as shown. One of them is a variable capacitor. This system makes up for a tuner circuit in radio.

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We have actually set up a tuner (resonator) for maintaining the required frequency. We also use a germanium diode and a resistor. The resistor is rated at 150K Ohm. When the resonator is used in a specific condition the resonance happens. In that condition, the circuit will provide clear sound which is required by us.

It is a very simple radio project. This can be made better with a lot more parts. We can add a better tuner, better range and more power as well. We wanted to make this short as possible just to give an idea to make it look simple and interesting for everyone.

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