Information is sent over these carrier waves by modifying the carrier waves with broadcast signals. Radiowaves are broadcasted using carrier waves of uniform wavelength and amplitude. Two example graphs show the relationship between broadcast signals, carrier waves and output signals. Figure 1 shows graphically how amplitude modulation works. The 'AM' in AM radio stands for 'amplitude modulation,' and the 'FM' in FM radio stands for 'frequency modulation.' A radio receiver removes the carrier wave and restores the original signal (the voice or music). The modulation can change either the amplitude or the frequency of the carrier wave. The carrier wave is modulated (varied) in direct proportion to the signal (e.g., voice or music) that is to be transmitted. So how does a radio wave carry sounds such as voice or music to your radio receiver? The radio station broadcasts a carrier wave at the station's assigned frequency. AM radio signals are carried by medium frequency (MF) radio waves (530 to 1710 kilohertz (kHz) in North America, 530 to 1610 kHz elsewhere), and FM radio signals are carried by very high frequency (VHF) radio waves (88 to 108 megahertz (MHz)). Radio waves are divided into many sub-classifications based on frequency. Electromagnetic radiation at frequencies ranging from 3 hertz (Hz) to 300 gigahertz (GHz) are classified as radio waves. For example, electromagnetic radiation at frequencies between about 430 terahertz (THz) and 750 THz can be detected by the human eye and are perceived as light. In a vacuum, electromagnetic waves travel at the speed of light.Įlectromagnetic waves such as light, x-rays, and radio waves are classified by their frequency or wavelength.

Electromagnetic radiation is a propagating wave in space with electric and magnetic components. When you listen to an AM or FM radio station, the sound that you hear is transmitted to your radio by the station using electromagnetic radiation as a carrier-radio waves. For example, light is electromagnetic radiation and so are x-rays. scanner that has specific digital features some don't.Electromagnetic radiation is all around us. site I mention here and look up what you need but you need to post what area you are in, as in nation, state and county and what you are interested in hearing, because each state/county has different requirements in a scanner. If you want clean, simple police scanner just go to that radioref. You can also TRY and wangle with an SDR dongle, the RTL2832 usb stick from China (around $20) but it requires a bit of technical knowledge to get it to work to receive such complex things as scanner chatter- as in installing complicated programs etc. Original price on those is about 599., but they are clearing them out for new stock. You will probably need whats called a trunk tracker digital scanner, those can run several hundred dollars - unless your police dept is in USA and also happens to use APCO25 'phase 1' you might find a Uniden scanner ON SALE or Clearance for around $ if you are Lucky. Go to radioreference dot com and get help there on what you will need to receive police scanner chatter. My Thursday adjustments made it into a nice working radio. This little radio must have been put together on a Monday. One of the adjustments on the main tuning capacitor made a hugh improvement to the reception. This radio does not have the small square tuning transformers. Yeah! The radio reception still sucked though, so I went a bit further and 'messed' with the main tuning capacitor. I replaced the broken antenna, but I then noticed that the radio would not pick up anything above 103.xx Using your instructions to increase the range I was able to put the station 104.3 right back on the dial where it is supposed to be. Not that this little radio is worth my time, but I was curious to see if I could make something out of it. The radio reception absolutely sucked at her camp so I gave her a multi-band radio and she can now listen to her favourite station.

I do not know if they had opened it up and disturbed the copper coils or not. A friend had this little cheap Chinese AM/FM radio and they had broken the antenna. I actually didn't use the instructions as you meant them to be used here.not exactly. Thank you Kipkay this was just the information I was looking for, and I fixed my radio.

Building a transistor radio