DIY AM Voice transmitter schematics
DIY AM Voice transmitter schematics

We all live in a world obsessed with technology. Almost everyone has a mobile phone these days. Teenagers mostly indulge in social media like Facebook, Twitter, Instagram, etc. The basic lifeline of all this communication is the “Internet”. Most people use WiFi from Broadband connections or mobile data. No disaster comes with prior notice. Imagine a situation after a disaster where there is no internet, mobile network, landline or any other digital communication. In such a case, a simple DIY AM voice transmitter can be a lifesaver.

AM stands for Amplitude Modulation and FM stands for Frequency Modulation. Both use different technology to make communication possible. There are many benefits of FM but, the AM transmitters and receivers are very easy to make and use. These things remain off-grid from internet and other digital connections. It is very easy to make and simple.

Spies have been using it since World War I as a bug. These days most mobile phones also don’t have FM support. In this situation, a handy AM Transmitter can be a lifesaver. If you are a far thinker then always keep a bag ready for emergencies. For such people, this device is a must. This project is for the geeks, nerd and even normal people. It is always fun to make things on your own. We can gain great knowledge and skill with projects like this.

Building Steps

In order to build a simple low power AM transmitter, we need a few things. Some basic things are wire, soldering iron, solder, and electrical tape. Be very careful while working if heated soldering iron. Also, keep working space clear and read instructions carefully. These are some of the basic things that you need to build or transmitter.

1) Power supply – 9V Battery
2) Battery Clip
3) Circuit Board
4) Audio Transformer- 1000 Ohm to 8 Ohm
5) 1 Mhz Crystal Oscillator
6) 1 Microphone (Mic)

People with a good online market in their countries can order the parts easily. Other people should try to find parts in their local market. For people living in Kathmandu, we recommend Bhedasing, Bangemudha. We can also extract a mic from an old headset. PC headset has a mic which works perfectly. People living in the US can easily buy parts from Radio Shack and other sources. To build, please refer to the schematic diagram in this article.

Explanation and Process

The 1000 ohm winding of the transformer is connected to the mic as shown. Then one end of the 8-ohm winding is connected to the positive lead of the battery. Another end is connected to one end of 1 MHz Oscillator. The negative lead of the battery is connected to another point just below the antenna’s point. One terminal of the oscillator is left open as shown in the schematic diagram above. Use connecting wires of suitable size and solder them so that they will have a strong connection.


Also Read: DIY AM Reciever Project

You can use an audio input jack such as a 3.5 mm jack to feed in audio from another source. The audio emitted by this transmitter can be easily caught by normal AM radio receiver. One thing to be careful is not making the transmitting antenna bigger than 12 inches. Doing so can interfere with other signals. This project should be kept as small as possible. We recommend extending the antenna only in the case of an emergency. Let us hope that we shall be ready with our emergency equipment during a calamity.

Communication is one of the most important things during an emergency. We do need good food, sanitation, and place to live during such times. But we first try to contact our loved ones. Most of the times, normal cell phones, the internet go down and transmitter can be very beneficial.


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