The Other Side of Mae: Monday Matters: How Radio Stations Work

Monday Matters is dedicated to all things that matter.

Have you ever wondered how radio stations work? Has it ever crossed your mind the difference between AM radio and FM radio? How about the four letters that serve as the name for each radio station? You probably listen to your radio every day but just don't have the attention to mind. Well for this blog entry, I would like to share to you what me and my students learned during our mini field trip / educational tour to DXDD AM and FM Ozamis!

Last semester, me and my students had learned about electromagnetic waves in our Electromagnetism II class in school. Electromagnetic waves are transverse waves without a medium that is, they can travel through empty space. They travel as vibrations in electrical and magnetic fields thus having some magnetic and electrical properties. The following image is the electromagnetic spectrum which is the range of electromagnetic waves when placed in order of increasing frequency:

Photo from Web

As you might notice, radio waves have the longest wavelengths but have the lowest frequencies. This means that radio waves are not harmful to the human body compared with the X-rays and gamma rays that have the highest frequencies.

Since we are now talking about frequencies, each radio station in an area broadcasts at a certain frequency. The number on the radio dial tells us the radio station's specific frequency. Say for example, 100.7 DXDD FM. That means that the radio station is broadcasting an FM (Frequency Modulated) radio signal at a frequency of 100.7 megahertz (MHz) with NTC-assigned call letters DXDD (NTC stands for the National Telecommunications Commission, a Philippine government agency). The Philippine pre-assigned call letters are DZ for Manila, DW for Luzon, DY for Visayas, and DX for Mindanao. According to DJ Carlo of DXDD FM Cool Radio, the last two letters would be at the prerogative of the radio station upon application for operation and with the approval of NTC of course.

On the other hand, AM (Amplitude Modulated) radio is confined to a band from 535 kHz to 1, 700 kHz. In the case of DXDD AM, they are broadcasting at 657 kHz. Now you might be asking what's the difference between MHz and kHz. The metric prefix mega- is greater than the metric prefix kilo- meaning, FM stations require higher frequencies than AM stations as shown in the diagram below:

Photo from Web

Aside from that difference, DJ Carlo also jokingly said that AM stands for Alay Music while FM stands for Furo Music! Now that is ingenious and definitely true!

Now enough with the theory part and let's go to the technical part! Radio stations nowadays are already hi-tech! Things got smaller and smaller compared with what were used in the olden times that could took up a whole room. Today, only computers, studio control consoles, and microphones are seen inside the radio booth while in the technical room, telephones and VHF/UHF radios are on hand for direct communication with field reporters and listeners.

Hi-Tech Gadgets Used in DXDD AM and FM

From the DJ and broadcaster's booth, the signal is sent out of the studio to the equipment room and into an audio processor to tailor the sound. Then it is transferred to the transmitter to generate and transmit the electromagnetic waves carrying the messages and signal. After that, the signal goes up to the tower on a big cable and for DXDD's case, the tower is located at Brgy. Tinago of this city. Finally, on top of the tower is the antenna that sends the radio waves to our radios at home which now convert the radio waves into sound waves. So from the very complicated processes, we then enjoy listening to AM's news and current event discussions and FM's music!

DJ Carlo Explaining to Us How the Studio Console Works

Sir Jovir on Audio Processing and Transmission

Fr. Edgar on Air (Haven't Took a Photo of Me on the Other Mic During the Interview)

With Broadcast Journalist, Ms. Thata Roxas

Through this mini field trip, me and my students had fully understood Electromagnetism in its real, seen, and tangible field of application. Thanks to the good and awesome people of DXDD AM and FM for accommodating us and teaching us how radio stations work! And for our Basic Electronics class this semester, we hope that we could assemble a simple yet useful electronic device. So this would be Physics made easy! :)