INTRODUCTION

Radio broadcastingis aone-waywirelesstransmission overradio wavesintended to reach a wideaudience. Stations can be linked in radioto broadcast a commonradio format, either inbroadcast syndicationorsimulcastor both. Audio broadcasting also can be done viacable radio, local wiretelevision networks,satellite radio, andinternet radioviastreaming mediaon theInternet. The signal types can be eitheranalog audioordigital audio. Radio is the transmission of signals by modulation of electromagnetic waves with frequencies below those of visible light.

Amplitude Modulation (AM) is a way of broadcasting radio signals. It transmits the information in the form of electromagnetic waves.AM works by modulating (varying) theamplitudeof the signal or carrier transmitted according to the information being sent, while the frequency remains constant.

The Radio Broadcasting Industry in the Philippines has gone through several changes throughout its nearly eight decades of history. From its fetal stages of pure entertainment, to its adoption of its role as a tool for information in the late 40s.

In the present time, Davao City has five AM Radio Stations: 576 AM- Bombo Radyo Davao, 621 AM- RMN Davao, 1125 AM- Super Radyo Davao, 1296 AM- Radyo Patrol Davao, 1404 AM- Kingdom Radio.DESIGN BACKGROUND

The to be established AM station, DXJC 1287 kHz, is anews/talkradio stationserving mainly inBo. Obrero, Davao City with a power of 2500 watts. The station'sstudio, as well as the transmitter, will be assembled in the fifth floor of the College of Engineering building in the University of Southeastern Philippines. DXJC will operate 20 hours a day, from 4 oclock in the morning until midnight, 7 days a week.

DESIGN CONCEPT

a.) Frequency For the project, a frequency of 1287 kHz is used. A channel at the high end of the mediumwave band (526.5 - 1606.5 kHz) is selected because the antennas needed are smaller than at lower frequencies, and the night time range enhancement is greater.b.) Type of ModuleSince the coverage area is relatively small, DXJC will broadcast in mono where typically there is only onemicrophone, oneloudspeaker, or (in the case ofheadphonesand multiple loudspeakers) channels are fed from a commonsignalpath. In the case of multiple microphones the paths are mixed into a single signal path at some stage. Aside from mono being less expensive for recording and reproduction, recording is easy and only requires basic equipment.

c.) Station LocationThe station, as well as the transmitter, will be located at the fifth floor of the College of Engineering building in the University of Southeastern Philippines. The area of coverage will be mainly Bo. Obrero, Davao City with a land area of approximately 800,000 square meters.Below are the topographical map of Davao City and the elevation profile of Obrero, Davao City.Topographic Map

Elevation Profile of Bo. Obrero, Davao City

System of Designing

i. Equipment Configuration

ii. Transmitter Design

a.) RF Oscillator stage This stage produces the carrier frequency of the AM Station. The oscillator is a Crystal oscillator made of resonant quartz crystal.

b.) Buffer Buffer amplifier is used to match the output impedance of the oscillator to the input impedance of the frequency multiplier.

c.) Frequency Multiplier This generates higher harmonics of the oscillator carrier frequency, it is a tune circuit that can be tuned to the requisite carrier frequency that is to be transmitted, which is 1287 kHz.

d.) Power Amplifier It is a class C amplifier that gives high power current pulses of the carrier signal at its output. It is a high-level transmitter.

e.) Audio driver and Audio power amplifiers The audio driver amplifier amplifies the audio produced at the station, it is then power amplified by a class A or B power amplifier.

f.) Modulated Power Amplifier This is the output stage of the transmitter. The class C amplifier amplifies the power of the AM signal to the reacquired transmitting power, which is 2.5 kilowatts. This signal is finally passed to the antenna, which radiates the signal into space of transmission.

iii. Sound ReproductionOur station will be using monaural sound reproduction, often referred to as monophonic sound or simply mono, which is practical since we use voice frequencies most of the time. Monaural sound reproduction typically has only one microphone or speaker, in the case of multiple sound sources, a common signal path will be used where all the sound sources are fed.

iv. The Antennaa. Radiating Element

The radiating element should be constructed vertically and made as tall and "fat" as possible. If the length of the radiating element falls short of being a full quarter wavelength at the operating frequency, a capacitive "hat" should be added. This makes the antenna look longer electrically and thus improves radiation efficiency. Output Power = 2.5 kilowatts (ERP) Operating Frequency = 1287 kHz Field Strength at 30 km = =2.025/106.347=0.019 mV/m

bThis is the radiation pattern for a 3dBi omnidirectional antenna, the most practical one for our application. This makes the shape of a donut. As long as you are inside of the red lines you have a 3 dBi gain, but if you get outside of the line you have no reception. This means that you can fly twice as far away from yourself as long as you dont fly outside of the reception field.

b. Grounding System Eight evenly-spaced radial wires 43 meters in length Buried 6-8 inches below groundGrounding is another important factor that will give the station a better coverage. In this design, we will use a large number of radial wires, defined as 120 radials, 90 electrical degrees in length, composed of #10 soft-drawn bare copper wire buried at least six to eight inches underground.

STUDIO DESIGN

MARKETING, ADVERTISING AND PROMOTIONS

Radio Advertising Rates:

a.) Blocktime ratesPer Hour- 1,500/ broadcastPackage price: Monday- Friday, 15,000/monthPer Half Hour- 750/ broadcastPackage price: Monday- Friday, 7,500/month

b.) Tape Ads (Recorded Materials)30 Seconds- 500/ SpotPackage Price: 10, 000/month (4 Spots/Day)

COSTS AND BUDGETING

Listed in the table are the components used in the installation process which also includes the System Commissioning and Labor Cost. The total landed cost is inclusive of the Value Added Tax (VAT).Item #QTYUnitDescriptionPriceAmount

1125feetLDF4-50A 1/2" Andrew Heliax Coaxial Cable, Standard129.816,225.00

22pcsLMR-400-75 type N male plugs and grounding6,600.006,600.00

31pcsBehringer Ultramizer Audio Processor4,400.004,400.00

42pcsSHURE SM574,356.004,356.00

51pcsAltec Lansing VS2621 Speakers2,350.002,350.00

62pcsTechno Tamashi TH-1049599.00599.00

71pcsALTO Equalizer 31 band mono4,500.004,500.00

81pcsMICKLE MT7-USB Mixing Console4,999.004,999.00

91pcsMARTI STL 20M72,500.0072,500.00

101pcsProcaster AM Transmitter30,580.0030,580.00

112pcs800 ft. 10-Gauge Bare Copper Grounding Wire8,404.0016,808.00

121pcs10 kw Briggs and Stratton 30207 Generator101,156.00101,156.00

AM Station Studio Construction150,000.00150,000.00

12monthsBuilding Rental10,000.0010,000.00

Labor Cost63,760.95

TOTAL AMOUNT 425,073.00

RETURN ON INVESTMENT

I, Overall Investment = Php 188 682.90G, Gain from investment:Average gain from radio advertising approximately = t*aWhere: t = advertising airtime in sa= average radio advertising rateG=t*a = 5hrs(3600s/hr) * 800/60s G = 240 000ROI=(G-I)/I = (240 000 188 682.90)/188 682.90 = 0.2719 = 27.19% on daily basisROI=(G-I)/I = (240 000*30 188 682.90)/188 682.90 = 37.16 monthly basis

Republic of the PhilippinesUniversity of Southeastern PhilippinesCOLLEGE OF ENGINEERINGObrero Campus, Davao City

BROADCAST ENGINEERING AND APPLIED ACOUSTICS

DXJC 1287kHz

Submitted to:Engr. Joey Dela Cruz

Approved by:

Rudy M. AyentoUMBN Chief-Tech

Chiclet CoronadoDXUM-AM, Radyo UkayNetwork Traffic Clerk

Submitted By:Cedric D. ConolJoannacel A. Paraiso