FM Broadcasting Station Proposal
(Name of the Station)
by
Randy J. Alarcon
Keith Green F. Cabrera
Hanna Mae D. Cambronero
Charlz F. Fontamillas
Erickson D. Malate
Jett-Rett S. Santos
Antipas T. Teologo Jr.
Aaron M. Tiro
Kristine Jean Diane A. Virtudez
Jay Lyn A. Yao
Electronics and Communications Engineering TIP, 2007
A Proposal Report Submitted to the Electronics and Communications Department in Partial Fulfillment of the Requirements for the Course Subject
Broadcasting Engineering and Acoustics
Technological Institute of the Philippines
APPROVAL SHEET
This is to certify that we have read and examined the paper prepared by RANDY J. ALARCON, KEITH GREEN F. CABRERA, HANNA MAE D. CAMBRONERO, CHARLZ F. FONTAMILLAS, ERICKSON D. MALATE, JETT – RETT S. SANTOS, ANTIPAS T. TEOLOGO Jr, AARON M. TIRO, KRISTINE JD A. VIRTUDEZ, JAY LYN A. YAO entitled “FM Broadcasting Station Proposal” and hereby recommend that it be accepted as fulfillment of the practicum requirement for the Course Subject BROADCASTING ENGINEERING AND ACOUSTICS.
Panel Member 1 Panel Member 2
Committee Chair
This paper is hereby approved and accepted as a fulfillment of the requirement for the Course Subject BROADCASTING ENGINEERING AND ACOUSTICS.
Engr. Antipas T. Teologo Jr. Instructor, Broadcasting Engineering and
TABLE OF CONTENTS
Approval sheet 22222222222222222.. 2
Table of contents 22222222222222222.. 3 Abstract ... 4 Chapter I: Introduction 22222222222222222.. 5 Chapter II: Review of Related Literature
A. Broadcast Bands 22222222222222222.. 6 B. Broadcast Bands around the World 22222222.. 7 C. Pre-emphasis and De-emphasis 22222222.. 7
D. FM Stereo 22222222222222222.. 8
E. Dolby FM 22222222222222222.. 9
F. Adoption of FM broadcasting worldwide 22222222.. 9 G. Microbroadcasting 22222222222222222..11
FM Broadcast Standards 22222222..12
Classes of Stations 22222222..12
FM Broadcast Frequency Allocation 22222222..13 Radio – Frequency Protection Ratio (dB) ………..14 FM Transmitter Considerations 22222222..14 FM Stereo Broadcasting 22222222..16 Broadcast Transmission Services 22222222..16 Chapter II: Methodology 22222222222222222..17 Chapter IV: Result and Discussion 22222222..19 Chapter V: Conclusion and Recommendation 22222222..22 Chapter VI: Appendices
a. FM KBP Manual 22222222222222222..23 b. FM Studio Layout 22222222222222222..77 c. Block Diagram for FM Radio 22222222..78
d. Glossary 22222222222222222..79
e. References 22222222222222222..82
g. Pictures 22222222222222222..93
ABSTRACT
DZLA (DZ Logos Arithma) is an FM radio station operating at a frequency of 104.5 MHz. The location of it’s transmitter is at Tabuk, Kalinga with polar coordinates of 17˚24’ (Latitude) 121˚42’ (Longitude).
Tabuk came from the word "Tobog", a living stream that runs from the upper part of the municipality that flows down to the lower part of the town which waters the wide fields of the residents of the place. Its land area accounts to 741.70 hectares with a total population of 76,788 as of 2005 NSO census.
It has 42 barangays with only 8 urban barangays. The main source of living is farming due mainly to its wide tract of lands for agricultural production specially on palay. In fact, Tabuk is dubbed as the rice granary or the bread basket of the Cordillera.It has been also a consistent hybrid producer for the past two years.
Tabuk is a component city and capital of the province of Kalinga. According to the 2000 census, it has a population of 78,633 people in 13,985 households.
Tabuk became the Cordillera’s second city after Baguio and surpassed Bangued, the capital of Abra province on June 23, 2007, when 17,060 voters ratified Republic Act No. 9404, An Act Converting the Municipality of Tabuk into a
Component City of the Province of Kalinga to be Known as the City of Tabuk.
DZLA transmits a 5kW power with an ERP of 10kW. It has an Antenna Height Above Average Terrain (HAAT) of 200 ft. with an antenna gain of 3.01dB.
Chapter I: INTRODUCTION
In 1933, FM radio was patented by inventor Edwin H. Armstrong. FM uses frequency modulation of the radio wave to minimize static and interference from electrical equipment and the atmosphere, in the audio program. In 1937, W1XOJ, the first experimental FM radio station, was granted a construction permit by the FCC.
The first FM broadcasting stations were in the United States, but initially they were primarily used to broadcast classical music to an upmarket listenership in urban areas and for educational programming. By the late 1960s FM had been adopted by fans of "alternative rock" music, but it wasn't until 1978 (the first year that listenership to FM stations exceeded that of AM stations) that FM became mainstream. During the 1980s and 1990s, Top 40 music stations and later even country music stations largely abandoned AM for FM. Today AM is mainly the preserve of talk radio, religious programming, ethnic (minority language) broadcasting and some types of minority interest music. Ironically, this shift has transformed AM into the "alternative band" that FM once was.
After World War II, the FM radio broadcast was introduced in Germany. In 1948, a new wavelength plan was set up for Europe at a meeting in Copenhagen. Because of the recent war, Germany (which did not exist as a state and so was not invited) was only given a small number of medium-wave frequencies, which are not very good for broadcasting. For this reason Germany began broadcasting on UKW ("Ultrakurzwelle", i.e. ultra short wave, nowadays called VHF) which was not covered by the Copenhagen plan. After some amplitude modulation experience with VHF, it was realized that FM radio was a much better alternative for VHF radio than AM. Because of this history FM Radio is still referred to as "UKW Radio" in Germany. Other European nations followed a bit later, when the superior sound quality of FM and the ability to run many more local stations because of the more limited range of VHF broadcasts were realized.
The radio frequency spectrum used for FM is from 88 MHz to 108 MHz and is divided into 100 channels. Each channel has a band of frequency 200 kHz wide. The channels for FM broadcast station starts at 88.1 MHz and ends at 107.9 MHz. The FM broadcast station employs frequency modulation. Frequency modulation is a system of modulation where the instantaneous frequency varies in proportion to the instantaneous amplitude of the modulating signal, and the instantaneous radio frequency is independent of the frequency of the modulating signal.
Broadcast stations in the Philippines are divided into classes. Class-A station transmitter power must not exceed 25kW and an ERP not exceeding 125kW and limited in HAAT of 2,000 ft. The minimum transmitter power shall be 10kW. Class-A stations are only allowed in Metro-Manila and Metro-Cebu. Class-B station transmitter power must not exceed 10kW and an ERP not exceeding 30kW with HAAT of 500 ft. The minimum transmitter power shall be 1kW. A Class-C station is a non-commercial, community station having an authorized ERP of 1,000 watts. A Class-D station transmitter power must not exceed 10 watts. Educational stations are under this class.
Chapter II. REVIEW OF RELATED LITERATURE
A. Broadcast Bands
The original FM broadcast band in the United States until 1946 was on 42 to 50 MHz with 0.2 MHz channel spacing. This band was abandoned after World War II and is now allocated to fixed, mobile, and land mobile radio services.
The term "FM band" can upset purists, because it conflates a modulation scheme with a range of frequencies. It is effectively shorthand for 'frequency band in which FM is used for broadcasting'. The exact range of frequencies used varies around the world, but always falls within the VHF part of the radio spectrum. The term "VHF" was previously in common use for "FM" within the EU. ("UKW," which stands for "Ultrakurzwellen" in German, meaning "ultra short wave", is still widely used in Germany.).
B. Broadcast Bands around the World
Throughout the world, the broadcast band is 87.5 to 108.0 MHz, or some portion thereof. In the U.S. it is 87.8 to 108.0 MHz. Japan is the only exception, using the 76 to 90 MHz band with 0.1 MHz channel spacing. In the former Soviet republics, and some Eastern Bloc nations, an additional older band from 65.9 to 74 MHz is also used. Assigned frequencies are at intervals of 30 kHz. This band, sometimes referred to as the OIRT band, is slowly being phased out in many countries. The frequency of an FM broadcast station (more strictly its assigned nominal centre frequency) is usually an exact multiple of 100 kHz. In most of the Americas and the Caribbean, only odd multiples are used. In some parts of Europe, Greenland and Africa, only even multiples are used. In Italy, "half-channel" multiples of 50 kHz are used. There are other unusual and obsolete standards in some countries, including 0.001, 0.01, 0.03, 0.074, and 0.3 MHz.
C. Pre-emphasis and De-emphasis
Random noise has a 'triangular' spectral distribution in an FM system, with the effect that noise occurs predominantly at the highest frequencies within the baseband. This can be offset, to a limited extent, by boosting the high frequencies before transmission and reducing them by a corresponding amount in the receiver. Reducing the high frequencies in the receiver also reduces the high-frequency noise. These processes of boosting and then reducing certain frequencies are known as emphasis and de-emphasis, respectively. The amount of pre-emphasis and de-pre-emphasis used is defined by the time constant of a simple RC filter circuit. In most of the world a 50 µs time constant is used. In North America, 75 µs is used. This applies to both mono and stereo transmissions and to baseband audio (not the subcarriers).
The amount of pre-emphasis that can be applied is limited by the fact that many forms of contemporary music contain more high-frequency energy than the musical styles which prevailed at the birth of FM broadcasting. They cannot be
pre-emphasized as much because it would cause excessive deviation of the FM carrier. (Systems more modern than FM broadcasting tend to use either programme-dependent variable pre-emphasis, e.g., dbx in the BTSC TV sound system, or none at all.). The problems with pre-emphasis due to the high frequency energy in modern music can be greatly attenuated using psychoacoustics principles, as Oscar Bonello demonstrates in his March 2007 AES paper. A new device, the IM cancelled high frequency clipper, is able to produce heavy audio clipping at high audio frequencies, with low listener fatigue.
D. FM Stereo
In the early 1960s, several systems to add stereo to FM radio were considered by the FCC, including one submitted by E. H. Armstrong, the inventor of FM, which avoided many of the problems with the Zenith-GE pilot tone multiplex system. The Armstrong system was rejected by the FCC because it did not allow sub-carrier services, and the Zenith system has become the standard method in most countries.
It is important that stereo broadcasts should be compatible with mono receivers. For this reason, the left (L) and right (R) channels are matrixed into sum (M) and difference (S) signals, i.e. M = (L+R)/2 and S = (L−R)/2. A mono receiver will use just the M signal. A stereo receiver will matrix the M and S signals to recover L and R: L = M+S and R = M−S.
The M signal is transmitted as baseband audio in the range 30 Hz to 15 kHz. The S signal is amplitude-modulated onto a 38 kHz suppressed carrier to produce a double-sideband suppressed carrier (DSBSC) signal in the range 23 to 53 kHz.
A 19 kHz pilot tone, at exactly half the 38 kHz subcarrier frequency and with a precisely defined phase relationship to it, is also generated. This is transmitted at 8-10% of overall modulation level and used by the receiver to regenerate the 38 kHz subcarrier with the correct phase.
The final multiplex signal from the stereo generator is the sum of the baseband mono audio (M), the pilot tone, and the DSBSC subcarrier. This multiplex, along with any other subcarriers, modulates the FM transmitter.
Converting the multiplex signal back to left and right is performed by a stereo decoder, which is built into stereo receivers.
In order to preserve stereo separation, it is normal practice to apply pre-emphasis to the left and right channels before matrixing, and to apply de-pre-emphasis at the receiver after matrixing.
Stereo FM signals are far more susceptible to noise and multipath distortion than mono FM signals. This is due to several factors, including the following:
• the addition of the two sidebands of the difference subcarrier to the baseband signal increases the noise bandwidth of the signal by a factor of three (9.5 dB) as compared with a mono signal.
• as mentioned above, the pre-emphasis is applied to the audio signals before encoding. This results in the pre-emphasis acting in the wrong direction on the lower sideband of the difference subcarrier, i.e. decreasing the level as the frequency rises, which will have a further deleterious effect on the S/N of the difference signal.
For this reason many FM stereo receivers include a stereo/mono switch to allow listening in mono when reception conditions are less than ideal, and most car radios are arranged to reduce the separation as the S/N ratio worsens, eventually going to mono while still indicating a stereo signal is being received.
In addition, the reception of vertically and horizontally polarised signals at different phase relationships from the same transmitter site will further corrupt stereo reception and invoke an earlier resolution within the receiver to mono presentation.
A short lived quadraphonic version of the Zenith-GE system used an additional subcarrier at 76 kHz.
E. Dolby FM
A commercially unsuccessful noise reduction system used with FM radio in some countries during the late 1970s, Dolby FM used a modified 25 µs pre-emphasis time constant and a frequency selective companding arrangement to reduce noise. See: Dolby noise reduction system.
Despite having been developed in the 1940s, FM broadcasting took a long time to be adopted by the majority of radio listeners.
The first FM broadcasting stations were in the United States, but initially they were primarily used to broadcast classical music to an upmarket listenership in urban areas and for educational programming. By the late 1960s FM had been adopted by fans of "alternative rock" music, but it wasn't until 1978 (the first year that listenership to FM stations exceeded that of AM stations) that FM became mainstream. During the 1980s and 1990s, Top 40 music stations and later even country music stations largely abandoned AM for FM. Today AM is mainly the preserve of talk radio, religious programming, ethnic (minority language) broadcasting and some types of minority interest music. Ironically, this shift has transformed AM into the "alternative band" that FM once was.
Belgium, the Netherlands, Denmark and particularly West Germany were among the first countries to adopt FM on a widespread scale. Among the reasons for this were:
1. The medium wave band in Western Europe is heavily overcrowded, leading to severe interference problems and, as a result, most MW frequencies are suitable only for speech broadcasting.
2. Particularly in Germany after World War II, the best available medium wave frequencies were used by the Allied occupation forces both for broadcasting entertainment to their troops and for broadcasting cold war propaganda across the Iron curtain
The regional structure of German broadcasting meant that the few remaining AM frequencies available for civilian domestic broadcasting fell far short of the number required and the broadcasters looked to FM as an alternative
Public service broadcasters in Ireland and Australia were far slower at adopting FM radio than those in either North America or continental Europe. However, in Ireland several unlicenced commercial FM stations were on air by the mid-1980s. These generally simulcast on AM and FM.
In the United Kingdom, the BBC began FM broadcasting in 1955, with three national networks carrying the Light Programme, Third Programme and Home
Service (renamed Radio 2, Radio 3 and Radio 4 respectively in 1967). These three networks used the sub-band 88.0 - 94.6 MHz. The sub-band 94.6 to 97.6 MHz was later used for BBC and local commercial services. Only when commercial broadcasting was introduced to the UK in 1973 did the use of FM pick up in Britain. With the gradual clearance of other users (notably Public Services such as police, fire and ambulance) and the extension of the FM band to 108.0 MHz between 1980 and 1995, FM expanded rapidly throughout the British Isles and effectively took over from LW and MW as the delivery platform of choice for fixed and portable domestic and vehicle-based receivers.
In addition, Ofcom (previously the Radio Authority) in the UK issues on demand Restrictive Service Licences on FM and also on AM (MW) for short-term local-coverage broadcasting which is open to anyone who does not carry a prohibition and can put up the appropriate licensing and royalty fees. In 2006 almost 500 such licenses were issued.
FM started in Australia in 1947 but did not catch on and was shut down in 1961 to expand the television band. It was not reopened until 1975. Subsequently, it developed steadily until in the 1980s many AM stations transferred to FM because of its superior sound quality. Today, as elsewhere in the developed world, most Australian broadcasting is on FM - although AM talk stations are still very popular.
Most other countries expanded their use of FM through the 1990s. Because it takes a large number of FM transmitting stations to cover a geographically large country, particularly where there are terrain difficulties, FM is more suited to local broadcasting than national networks. In such countries, particularly where there are economic or infrastructural problems, "rolling out" a national FM broadcast network to reach the majority of the population can be a slow and expensive process.
G. Microbroadcasting
Low-power transmitters such as those mentioned above are also sometimes used for neighborhood or campus radio stations, though campus radio stations are often run over carrier current. This is generally considered a form of microbroadcasting. As a general rule, enforcement towards low-power FM stations is
stricter than AM stations due to issues such as the capture effect, and as a result, FM microbroadcasters generally do not reach as far as their AM competitors
A. FM Broadcast Standards
Parameters Philippine Standards
Frequency Band 88 -108 MHz
No. of Channels 25
Bandwidth per Channel 200 kHz
Permitted Bandwidth 240 kHz (monophone)
Channel Spacing 800 kHz
Center Frequency Stability ± 2 kHz
Baseband Frequency 50 - 15000 Hz
Type of Modulation FM
Type of Emission F3E
Guardband 25 kHz above Upper Side Band
25 kHz below Lower Side Band Frequency Deviation ± 75 kHz (for 100% modulation)
Pre-Emphasis 75us time constant
Pilot Subcarrier 19 kHz
Antenna Polarization Horizontal or circularly-polarized
Type of Receiver Superheterodyne
Intermediate Frequency 10.7 MHz
B. Classes of Stations
Stations Authorized Power
Class A Not exceeding 15 kW
Class B Not exceeding 10 kW
Class C Not exceeding 1 kW
C. FM Broadcast Frequency Allocation
FMn = FM1 + (n – 1)BW (MHZ) Where: FM = Chanel Frequency in MHz
FM1= Frequency in the 1st FM Channel (88.1MHz)
n =Channel number
BW = Channel Bandwidth (200kHz)
Philippine Major Cities Frequency Assignments
Channel No. Frequency (MHz)
FM2 88.3 FM6 89.1 FM10 89.9 FM14 90.7 FM18 91.5 FM22 92.3 FM26 93.1 FM30 93.9 FM34 94.7 FM38 95.5 FM42 96.3 FM46 97.1 FM50 97.9 FM54 98.7 FM58 99.5 FM62 100.3 FM66 101.1
FM70 101.9 FM74 102.7 FM78 103.5 FM82 104.3 FM86 105.1 FM90 105.9 FM94 106.7 FM98 107.5
D. Radio – Frequency Protection Ratio (dB)
Freq Monophonic Stereophonic
Spacing Steady Tropospheric Steady Tropospheric (kHz) Interference Interference Interference Interference
0 36 8 45 37 25 31 12 51 43 50 24 16 51 43 75 16 22 45 37 100 12 27 33 25 150 8 28 18 14 200 6 6 7 7 250 2 2 2 2 300 -7 -7 -7 -7 350 -15 -15 -15 -15 400 -12 -20 -20 -20 E. FM Transmitter Considerations 1. Construction
The transmitter shall be constructed either on racks and panels or in totally enclosed frames protected as required by the Philippine Electronics Code and the Philippines Electrical Code.
2. Enclosure
The transmitter shall be enclosed in the metal frame or grille
separated from the operating space by a barrier or other equivalent means.
3. Grounding of Controls
All external metallic handles and controls accessible to the operating personnel shall be effectively grounded.
No circuit in excess of 150 V shall have any part exposed to direct contact.
4. Interlocks
All access doors shall be provided with interlocks which will
disconnect all voltage sin excess of 350 V when any access door is opened.
5. Bleeder Resistor
Proper bleeder resistor or other automatic means shall be installed across all capacitor banks to lower any voltage which may remain accessible with access door open, to less than 350 V within 2 seconds after the access door is opened.
6. Wiring and Shielding
Wiring between units of the transmitter, with the exception of circuits carrying radio frequency energy, shall be installed in conduits of fiber or metal raceways for protection from mechanical injury.
All instruments having one more than 1,000 v potential to ground shall be protected by a cage or cover.
F. FM Stereo Broadcasting
Two audio channels (L and R) are mixed to provide two new signals. The first is the sum of the two input channels (L+R), and the second is the difference of the two (L-R).
The sum channel (L+R) is modulated directly n the baseband assignment between 50 and 15 kHz.
The difference signal (L-R) is DSBSC modulated in the 23 to 53 kHz slot about a stereophonic Subarrier of 38 kHz.
Some FM stations are frequency division multiplexing an additional
channel on their carrier for the purpose of providing background music for public buildings, a system licensed as
Subsidiary Communications Authorization (SCA)
Parameters Philippine Standards
Pilot Subcarrier 19 kHz ± 2Hz
Stereophonic Subcarrier 38 kHz (2nd harmonic of Pilot Subcarrier) Stereophonic Subcarrier suppression
level
< 1% modulation of the main carrier
G. Broadcast Transmission Services
1. Studio-to-transmitter Link (STL) – stations in this service are to be used for relay of aural programming materials from studio to transmitter and between fixed facilities in other locations.
STL Frequency Band Allocation
Band A 310 – 315
Band B 734 – 752
860 – 880 942 - 953
2. Remote Pickup Broadcast Stations – stations in this service are to be used for the transmission of aural programming materials and associated cues and data.
Remote Pickup Band Allocation
Band Frequency (MHz)
Band A 305 – 310
Band B 450 – 451
Band C 455 - 456
3. Communications, Coordination, and Control Links
Band Allocation Band Frequency (MHz) Band A 4 -12 Band B Band C 26.10 – 26.48 162.235 – 162.615 166.250 170.150 Band D 880 - 890
Chapter III. METHODOLOGY
In designing a broadcasting station, these procedures must be followed:
1. Assign a frequency ranging from 88.3 MHz to 107.9 MHz to be used by your broadcasting station.
2. Specify the antenna height above average terrain (HAAT), the effective radiated power (ERP), the transmitted power and the location of the station (choose a province with no station above or below 800kHz of your channel frequency).
3. List all the Co-channels, 1st Adjacency channels and 2nd Adjacency channels with their corresponding ERP and locations.
4. Using the FM Contour Chart and a slider (used when the ERP is more than 1kW), locate the ERP of the each channels in the slider and place it on the center line (or on the 40dB field strength line) parallel to the HAAT of your station.
5. Draw a horizontal line corresponding to this dBu field strength (for co-channels use 60 dBu and 15 dBu, for 1st adjacency channels use 60 dBu and 53 dBu and for 2nd adjacency use 60 dBu and 80 dBu).
6. From the intersection of the two straight lines, determine which distance curve the intersection coincides with. Since the distance is in miles, convert it to kilometers.
7. Get the scale of your map (in this project, the scale is 0.058 cm for every kilometer) and convert your distances to cm. The distance of the stations is their corresponding radius in the map.
8. Locate each station in the map and plot their corresponding field strength in dBu (15, 53, 60 and 80) according to the computed radius.
9. Compute for the Aggregate and distance of the stations to your station location.
Chapter IV. RESULTS AND DISCUSSION
PREDICTION OF SERVICE AREA AND OF INTERFERENCE
FM RADIO BROADCAST STATION (CALL SIGN): DZLA FREQUENCY: 104.5 MHz
LOCATION OF TRANSMITTER: TABUK, KALINGA POLAR COORDINATES: 17˚24’ (Latitude) 121˚42’ (Longitude)
TRANSMITTER POWER: 5kW ERP: 10kW ANTENNA HEIGHT: 200 ft. ANTENNA GAIN: 3.01 dB EXTENT OF FIELDS IN KILOMETERS
80 dBu 60 dBu 53 dBu 15 dBu 10 mV/m 1 mV/m 446 uV/m 5.62 uV/m
8.53 25.75 37.01 214.04
BASIC CONSIDERATIONS:
1. Application for FM BROADCAST AUTHORIZATION must show two field strength contours, these are the 48 dBu (251 uV/m) and the 60 dBu (1 mV/m) contours.
2. THE ALLOCATION PROTECTION RATIOS FOR FM BROADCAST ARE AS FOLLOWS:
FREQUENCY FREQUENCY
RF SIGNAL RATIO RF PROTECTION ADJUSTMENT SEPARATION RATIO (dB) CO – CHANNEL 0 6O dBu : 53 dbu 45
1mV / m : 0.45.62 uV / m
FIRST ADJACENCY 200kHz 6O dBu : 15 dbu 7 (LOWER OR UPPER) 1mV / m : 0.466 mV / m
SECOND
ADJACENCY 400kHz 6O dBu : 80 dbu -20 (LOWER OR UPPER) 1mV / m : 10 mV / m
3. In predicting the distance to the field strength contours (EXTENT OF FIELDS) F (50,50) FM CHANNELS FIELD INTENSITY CHART (FCC) maybe used. The chart is based on an ERP of 1 kW. For other values of ERP, the accompanying sliders shall be used. The distance in miles obtained from use of the chart is converted to kilometers.
4. INTERFERENCE IS IMMINENT, when the aggregates sum of the “EXTENT OF FIELDS” of two stations (based on their frequency separation and RF protection ratio is greater than the physical distance between these two stations.
Chapter V. Conclusion and Recommendation
As a class B station operating at 10 kW ERP, DZLA has a high potential of becoming a prominent FM station at Tabuk Kalinga.
Aside the from the proper selection of its frequency that enables the station to avoid interference with other stations it is located in a place wherein it can have a full capacity of transmitting the signal to various places since the place is actually feasible. Only few will be wasted since the location of the station’s transmitter is located in the middle of Luzon and compared with other nearby stations, it has higher ERP which gives an advantage over its competitors.
The station, following all the standards set by the National Telecommunications Commission (NTC) and KBP, could be somehow seen as a giant FM station after five years and we, the Logos Arithma Inc., as the proponent of this design, strongly recommend our proposed FM radio station.
Chapter VI. Appendices
a. FM KBP Manual
FM BROADCASTING STANDARDS 1. INTRODUCTION
The increasing importance of the role of FM broadcasting in the Philippines has encouraged broadcast engineers and the National Telecommunications Commission to pool their resources together and come up with technical standards and rules and regulations relating to FM broadcast.
These technical standards and regulations were derived from CCIR recommendations, relevant engineering data and rules and regulations of the Federal Communication Commission, and other data supplied by manufacturers of radio equipment and by licensees of FM broadcast stations. These standards and regulations shall be revised from time to time to be effective and compatible with technical progress.
2. DEFINITION OF TERMS
2.1 FM broadcast band
That portion of radio frequency spectrum from 88MHz to 108 MHz. The band is divided into 100 channels.
2.2 FM broadcast channel
A band of frequencies 200 kilohertz wide and I designated by its center frequency. Channels of FM broadcast stations begin at 88.1 megahertz and continue in successive steps of 200 kilohertz to and including 107.9 megahertz.
2.3 FM broadcast station
A station employing frequency modulation in the FM broadcast band and intended to be received by the general public.
A system of modulation where the instantaneous frequency varies in proportion to the instantaneous amplitude of the modulating signal, and the instantaneous radio frequency is independent of the frequency of the modulating signal.
2.5 Center frequency
The carrier frequency allocated by the Authority.
2.6 Frequency Swing
The instantaneous departure of the frequency of the emitted wave from the center frequency resulting from modulation.
2.7 Antenna height above average terrain (HAAT) means
a. The height of the radiation center of the antenna above the terrain 3 to 16 kilometers from the antenna. (Generally, a different antenna height will be determined for each radial direction from the antenna. The average of these various heights is considered as the antenna height above average terrain).
b. Where circular or elliptical polarization is employed the antenna height above the average terrain shall be based upon the height of the radiation center of the antenna which transmits the horizontal components of radiation.
2.8 Antenna field gain
The ratio of the effective free space field intensity produced at 1.6 kilometers in the horizontal plane expressed in millivolts per meter for one (1) kilowatt antenna input power, to 137.6 millivolts per meter.
2.9 Antenna power gain
The square of the ratio of the root mean-square free space field strength produced at 1.6 kilometers in the horizontal plane, in milivolts per meter for one (1) kilowatt antenna power, to 137.6 milivolts per meter. This ratioshould be expressed in decibels (dB). (If specified for a particular direction, antenna power
gain is based on the field strength in that direction only).
2.10 Effective radiated power (ERP)
The product of the transmitted power ( transmitter output power les transmission line loss) multiplied by (a) the antenna power gain or (b) the antenna field gain squared. Where circular or elliptical polarization is employed , the term “effective radiated power” is applied separately to the horizontal and vertical components of radiation.
2.11 Field intensity
“Field intensity” as used in these standards shall mean the electric field intensity in the horizontal direction.
2.12 Free space field intensity
The field intensity that would exist at a point in the absence of waves reflected from the earth or other reflecting objects.
2.13 Service area
As applied to FM broadcasting, means the service resulting from an assigned effective radiated power and antenna height above average terrain.
2.14 Radio-frequency (RF) Protection Ratio
The value of the radio-frequency wanted-to-interfering signal ratio that enables, under specified conditions, the radio-frequency protection ratio to be obtained at the output of a receiver.
2.15 Percentage modulation
The ratio of the actual frequency swing to the frequency swing defined as 100 percent modulation, expressed in percentage. For FM broadcasting stations, a frequency swing +75 kilohertz is defined as 100 percent modulation.
2.16 Multiplexing
In its simplest sense, multiplexing implies that two or more independent sources of information are combined for carriage over a single medium, namely, the radio frequency “carrier”, and then are separated at the receiving end. In stereophonic broadcasting , for example, program information consisting of left and right audio signal are multiplexed onto an FM carrier for transmission to receivers which subsequently recover the original audio signals.
2.17 FM Stereophonic Broadcast
The transmission of a stereophonic program by a single FM broadcast station utilizing the main channel and a stereophonic sub-channel.
2.18 Channel
A transmission path. The distinction between the concept of a “Channel” and a “signal” are not always clear. The usage herein distinguishes between transmission channels; e.g., main channel, stereophonic subchannel, etc., and left and right audio “signal”.
2.19 Composite Baseband signal
A signal which is the sum of all signals which frequency-modulates the main carrier. The signal can be represented by a formula which includes all signal components: the main channel signal, the modulated stereophonic subchannel, the pilot subcarrier and the SCA subcarrier(s).
2.20 FM Baseband
The frequency band from 0 Hertz (Hz) to a specified upper frequency which contains the composite baseband signal.
2.21 Main Channel
which contains the main channel signal.
2.22 Main Channel Signal
A specified combination of the monophonic or left and right audio signals which frequency-modulates the main carrier.
2.23 Stereophonic Sound
The audio information carried by plurality of channel arranged to afford the listener a sense of spatial distribution of sound sources. Stereophonic sound includes, but is not limited to, biphonic (two channel), triphonic (three channel) and quadraphonic (four channel) services.
2.24 Stereophonic Sound Subcarrier
A subcarrier within the FM broadcast baseband used for transmitting signals for stereophonic sound reception of the main broadcast program service.
2.25 Stereophonic sound Subcarrier
The band of frequencies from 23 KHz to 99 KHz containing sound subcarriers and their associated sidebands.
2.26 Subchannel
A transmission path specified by a subchannel signal occupying a specified band of frequencies.
2.27 Subchannel Signal
Subcarrier(s) and associated sideband(s) which frequency-modulate the main carrier. It is synonymous with “subcarrier”, as in the stereophonic subcarrier or SCA subcarrier.
2.28 Pilot Sub-carrier
A pilot sub-carrier serving as a control signal for use in the reception of FM stereophonic broadcast.
2.29 Left (or Right) signal
The electrical output of a microphone or a combination of microphones placed so as to convey the intensity, time, and location of sounds originating predominantly to the listener’s left (or right) of the center of the performing area.
2.30 Left (or Right) stereophonic channel
The left (or right) signal as electrically reproduced in the reception of an stereophonic broadcast.
2.31 Stereophonic separation
The ratio of the electrical signal caused in the right (or left) stereophonic channel, to the electrical signal caused in the left (or right) stereophonic channel, by the transmission of only a right (or left) signal.
2.32 Frequency Deviation
The peak difference between the instantaneous frequency of the modulated wave and the carrier frequency.
2.33 Injection Ratio
The ratio of the frequency swing of the FM carrier by a subchannel signal to the frequency swing defined as 100 percent modulation, expressed in percentage. The total injection of more than one subchannel signal is the arithmetic sum of each subchannel.
2.34 Cross-talk
An undesired signal occurring in one channel caused by an electrical signal in another signal.
2.35 Linear Crosstalk
A form of “crosstalk” in which the undesired signal(s) is created by phase or gain inequalities in another channel or channels. Such crosstalk may be due to causes external to the stereophonic generator; consequently it is sometimes referred to as “system crosstalk”.
2.36 Nonlinear Crosstalk
A form of crosstalk in which the undesired signal(s) is created by harmonic distortion or intermodulation of electrical signal(s) in another channel or channels. Such crosstalk may be due to distribution within the stereophonic generator or FM transmitter; consequently it is sometimes referred to as “transmitter crosstalk”.
2.37 SCA
The term SCA is an acronym for a “subsidiary Communication Authority.”
2.38 Index of Cooperation
As applied to facsimile broadcasting, is the product of the number of lines per inch, the available length in inches, and the reciprocal of the line use ratio (e.g. 105 x 8.2 x 8/7 = 984).
2.39 Line-use ratio
As applied to facsimile broadcasting is the ratio of available line to the total length of scanning line.
Means the portion of the total length of scanning line that can be used specially for picture signals.
2.41 Rectilinear scanning
The process of scanning an area in a predetermined sequence of narrow straight parallel strips.
2.42 Optical density
The logarithm (to the base 10) of the ratio of incident to transmitter or reflected light.
2.43 Experimental period
The period between 12 midnight to 5:00 a.m. local standard time (1600-2100 GMT). This period may be used for experimental purposes in testing and maintaining apparatus by the licensee of any FM broadcast station on its assigned frequency and not in excess of its authorized power, provide no interference is caused to other station maintaining a regular operating schedule within such period.
2.44 Operating Power
This is the product of the plate voltage (Ep) and the plate current ( Ip) of the last ratio stage and efficiency factor, F, expressed: Operating power =Ep x Ipx F. This is the indirect method of determining the operating power of each FM station for the purpose of specifying the operating power range of FM transmitters. The factor F shall be established by the transmitted manufacturer for each type of transmitter and shall be specified in the instruction book (s) supplied to each customer with each transmitter.
2.45 Last radio stage
power to the antenna.
2.46 Qualified technician
As applied to FM broadcasting means a person who is a holder of any class of radio Telephone Operator’s License or its equivalent except those mention in Section 7.4 as issued by the existing regulatory body.
3. ALLOCATION OF FREQUENCY FOR FM BROADCAST STATION (See Table 1.)
4. CLASSES OF FM BROADCAST STATIONS.
4.1 Class-A Stations
A class-A station shall have an authorized transmitter power not exceeding 25 kilowatts and an Effective Radiated Power (ERP) not exceeding 125 kilowatts and limited in antenna height of 2,000 feet above average terrain. The minimum transmitter Power shall be 10 KW.
Class-A station shall only be allowed in Metro-Manila and Metro-Cebu.
4.2 Class-B station
A Class-B station shall have an authorized transmitter power not exceeding 10 kilowatts and an Effective Radiated Power not exceeding 30 kilowatts, and limited in antenna height of 500 feet above average terrain. The minimum transmitter power shall be 1 KW.
4.3 Class-C station
A Class-C station is a non-commercial, community station having an authorized radiated power not exceeding 1,000 watts (ERP).
4.4 Class-D station
watts.
Educational station shall be allowed to operate with Class-D transmitter power.
4.5 All classes of FM station shall be protected to the 1 mV/m cotour or 60 dBU contour.
4.6 Table of Assignments
The frequency assignment for the cities of Manila, Laoag, Legaspi, Cebu, Davao and Zamboanga shall be selected from table 2.
Table 2
Channel No. Frequency (mHz) 202 88.3 206 89.1 210 89.9 214 90.7 218 91.5 222 92.3 226 93.1 230 93.9 234 94.7 238 95.5 242 96.3 246 97.1 250 97.9 254 98.7 258 99.5 262 100.3 266 101.1 270 101.9
274 102.7 278 103.5 282 104.3 286 105.1 290 105.9 294 106.7 298 107.5
4.7 Radio frequency Protection Ratios
4.7.1 The following radio frequency protection ratios (Table 3) provide for the minimum physical separation between stations and protection of stations from Interference.
RADIO-FREQUENCY PROTECTION RATIOS (dB) (based on the horizontal component of radiation)
____________________________________________ Frequency
Spacing R.F. Signal Ratio (kHz)
____________________________________________
0 60 dBu : 15 dBu
200 60 dBu : 53 dBu
400 60 dBu : 80 dBu
4.7.2 Intermediate frequency amplifiers of most FM broadcast receivers are design to operate on 10.7 megaHertz. For this reason the assignment of two
stations in the same area, one with a frequency 10.6 or 10.8 mega-
Hertz removed from that of the other, should be avoided if possible.
4.7.3 FM Broadcast Stations, shall not be authorized to operate in the same city or in nearby cities with a frequency separation of less than 800 kHz.
4.7.4 The nature and extent of the protection from interference accorded the FM stations is limited solely to that which results from the application of the radio frequency protection ratio.
4.7.5 A commercial broadcast entity may establish only one primary FM radio station within the geographical boundaries of any province.
5 TECHNICAL REQUIREMENTS
5.1 Safety Requirements
5.1.1 Conformity with Electrical Wiring Rules
All equipment using electrical power shall conform with the provisions of the Philippine Electrical Code and the Philippines Electronics Code so as to ensure the safety of property, equipment, and personnel and the public in general.
5.1.2 All component parts shall be in accordance with generally accepted standards or those of the International Standards.
5.2 Transmitting Facilities
5.2.1 Location and Layout
the absence of other comparable sites, may be shared by and be made available to as many applicants as possible.
b. The transmitting site should be selected consistent with purpose of the station, i.e., whether it is intended to serve a small city, a metropolitan area, or a large region. The location should be so chosen that line-of-sight can be obtained from the antenna over the principal city or cities to be served.
5.2.2 Antenna System
a. It shall be standard to employ horizontal polarization. However circular or elliptical polarization of the clockwise or counter-clockwise rotation may be employed, if so desired.
b. The antenna must be constructed such that it is clear of surrounding buildings or objects that would cause shadow problems.
c. In the event a common tower is issued by two or more licensees for antenna and / or antenna supporting purposes, the licensee who owns the tower shall assume full responsibility for the maintenance of the tower structure, its painting and lighting requirements. In case of shared ownership, only one licensee shall assume such responsibility.
For the protection of air navigation, the antenna and supporting structure shall be painted and illuminated in accordance with ATO regulations.
5.2.3 Transmitter and Association Equipment a. Electrical Performance Standards
The general design of the FM broadcast transmitting system (from input terminal of the microphone preamplifier, through audio
facilities at the studio through lines or other circuits between studio and transmitter, through audio facilities at the transmitter, but excluding equalizers for the correlation of deficiencies in microphone response shall be in accordance with the following principles and specifications:
1) The transmitter shall operate satisfactorily in the operating power range with a frequency swing of + 75 kiloHertz, which is defined as 100 percent modulation.
2) The transmitting system shall be capable of transmitting a band of frequencies from 50 to 15,000 Hertz. Pre-emphasis shall employed in accordance with the impedance-frequency characteristics of a series inductance-resistance network havinga
time constant of 75 microseconds (See Annex Fig. 2). The deviation of the system response from the standard pre-emphasis
curve shall lie between two limits. The upper of these limits shall be uniform: (no deviation) from 50 to 15,000 Hertz. The lower the limit shall be uniform from 100 to 7,500 Hertz and 3 db the upper limit; from 50 to 100 Hertz and the lower limit shall fall from the 3 db limit at a uniform rate of 1 db per octave (4 db at 50 Hertz); from 7,500 to 15,000 Hertz, the lower limit shall fall from the 3 dB limit at a uniform rate of 2 dB per octave (5 dB at 15,000 Hertz).
3.) At any modulating frequency between 50 and 15,000 Hertz and at modulation percentages of 25, 50 and 100 percent combined audio frequency harmonics measured in the output of the system shall not exceed the root-mean-square values given in the following table:
Modulating
Frequency Distortion 50 to 100 Hz2222..3.5%
100 to 7,500Hz222...2.5% 7,500 to 15,000 Hz22.3.0%
4) Measurements shall be made employing a 75 microsecond de-emphasis in the measuring equipment and 75 microsecond pre-emphasis in the transmitting equipment, and without compression, if a compression amplifier is employed. Harmonics shall be included to 30,000 Hertz.
5) It is recommended that none of the three main divisions of the system (transmitter, studio to transmitter circuit, and audio facilities) contribute over one-half of these percentage since at some frequencies the total distortion may be come the arithmetic sum of the distortion of the divisions.
6) The transmitting system output noise level (frequency modulation) in the band of 50 to 15,000 Hertz shall be at least 60decibels below 100 percent modulation (frequency swing + 75 kilohertz).
The measurement shall be made using 400 Hertz modulation as a reference. The noise measuring equipment shall be provided with standard 75 microsecond de-emphasis; the ballistic characteristic of the instrument shall be similar to those of the standard VU meter.
7) The transmitting system output noise level (amplitude modulation) in the band of 50 to 15,000 Hertz shall be least 50 decibels below the level representing 100 percent modulation. The noise-measuring equipment shall be provided with a standard 75 microsecond de-emphasis; and the ballistic characteristics of the instrument shall be similar to those of the standard VU meter.
8) Automatic means shall be provided in the transmitter to maintain the assigned center frequency within the allowable
tolerance of (+ 2000 Hertz).
9) The transmitting shall be equipped with suitable indicating instruments for the determination of operating power and with other instruments as are necessary for proper adjustment, operation, and maintenance of the equipment.
10) Adequate provision shall be made for varying the transmitter output power to compensate for excessive variation in the line voltage or for others factors affecting the output power.
11) Allowances shall be provided in all component part to avoid overheating at the rated maximum output power.
12) If a limiting or compression amplifier is employed, precaution should be maintained in its connection in the circuit due to the use of pre-emphasis in the transmitting system.
13) Any emission appearing on a frequency removed from the carrier by between 120 kHz, and 240 kHz, inclusive, shall be attenuated at least 25 decibels below the level of the un-modulated carrier.
14) Any emission appearing on a frequency removed from the carrier by more than 240 kHz and up to and including 600 kHz shall be attenuated at least 35 db below the level of the unmodulated carrier.
15) Any emission appearing on a frequency removed from the carrier by more than 600 kHz shall be attenuated at least 43 +10 Log10 ( Power, in watts ) decibels below the level of the unmodulated carrier, or 80 decibels, whichever is the lesser attenuation.
b. Construction
In general, the transmitter shall be constructed either on rocks and panels or in totally en-closed frames protected as required by the Philippine Electronics Code and the Philippine
Electrical Code and those set forth below:
The transmitter shall comply with the following:
1) Enclosure. The transmitter shall be enclosed in a metal frame or separated from the operating space by a barrier or other equivalent means. All metallic parts shall be connected to ground.
2) Grounding of controls. All external metallic handles and controls accessibility to the operating personnel shall be effectively exposed to direct contact. A complete dead front type of switch-board is preferred.
3) Interlocks on doors.
a) All access doors shall be provided with interlocks which will disconnect all voltages in excess of 350 volts when any access door is opened.
b) Means shall be provided for making all tuning adjustment, requiring voltages in excess of 350 volts to be applied to the circuit, from the front of the panels with all access doors closed.
c) Proper bleeder resistor or other automatic means shall be installed across all capacitor banks to lower any voltage which may remain accessible with access door open to less than 350 volts within 2 seconds after the access door is opened.
d) All plate supply and other high voltage equipment, including transformer, filters, rectifiers and motor generator, shall be protected so as to prevent injury to operating personnel.
e) Power equipment and control panel of the transmitter shall meet the above requirements exposed 220 volts AC switching equipment on the front of the power control panel is not recommended.
1) The transmitter panels or units shall be wired in accordance with standard switchboard practice, either with insulated leads properly cabled and supported or with rigid bus bar properly insulated and protected.
2) Wiring between units of the transmitter, with the exception circuits carrying radio-frequency energy, shall be installed in conducts or approved fiber or metal raceways for protection from mechanical injury.
3) Circuits carrying radio-frequency energy between units shall be coaxial, or two-wire balanced lines, or properly shielded. 4) All stages or units shall be adequately shielded and filtered to prevent interaction and radiation.
d. Metering equipment
1) All instruments having more than 1,000 volts potential to ground on the movements shall be protected by a cage or cover. (some instruments are designed by the manufacturer to operate safely with voltages in excess of 1,000 volts on the movement). 2) In case the plate voltmeter is located on the low potential side of the multiplier resistor with the potential of the high potential terminal to the instrument at or less than 1,000 volts above ground, no protective case is required. However, it is good practice to protect voltmeters subject to more than 5,000 volts with suitable over-voltage protection device(s) across the instrument terminal in case the winding opens.
3) Transmission line meters and any other radio-frequency instrument which is necessary for the operator to read, shall be so installed as to be easily and accurately read without the operator risk contact with circuits carrying high potential radio-frequency energy.
e. Indicating Instruments
1) Each FM broadcast station should be equipped with indicating instrument for measuring the plate voltage and current of the last radio stage and the transmitting line radio frequency power. 2) In the event that the plate voltage or plate ampere in the last radio stage is defective, the operating power shall be maintained by means of the radio-frequency power meter.
f. Installation
1) The installation shall be made in suitable quarters.
2) Since an operator must be on duty at the transmitter control during operation, suitable facilities for his welfare and comfort shall be provided at the control point.
g. Other technical data. An accurate circuit diagram, as furnished by the manufacturer of the equipment, shall be retained at the transmitter location.
5.2.4 Monitoring Equipment a. Frequency Monitor
1) The licenses of each station have in operation, either at the transmitter or at the place where the transmitter is controlled, a frequency monitored of a type approved by the Commission which shall be independent of the frequency control of the transmitter.
2) In the event that the frequency monitor becomes defective, the station may be operated without such equipment pendings its repair or replacement for a period not in excess of 60 days without further authority of the Commission: Provided, That:
a) Appropriate entries shall be made in the operation log of the station to show the date and the time the monitor was removed from and restored to service.
b) The Engineer in Charge of the Region in which the station is located shall be notified both immediately after the monitor is found to be defective and immediately after the repaired or replacement monitor has been installed and is functioning properly.
c) The frequency of the station shall be compared with an external frequency source of known accuracy at sufficiently frequent interval to insure that the frequency is maintained with the tolerance. An entry shall be made in the station log as to the method used and the result thereof.
3) If conditions beyond the control of the licensee or permittee prevent the restoration of the monitor to service within the above allowed period, informal request may be filed with the Engineer in Charge of the Region in which the station is located for such additional time as may be required to complete rep[airs of the defective instrument or equipment.
Modulation Monitor
The modulation monitor (deviation monitor) is an optional requirement for an FM station. The FM station may refer to the monitoring section of the Authority, to the Standard Authority of the KBP of to other FM station for modulation measurements.
5.3 Stereophonic Transmission Standards
a. The modulating signal for the main channel shall consist of the sum of the left and right signals.
b. A pilot subcarrier at 19,000 Hertz plus or minus 2 Hz, shall be transmitted that frequency-modulate the main carrier between the limits of 8 to 10 percent.
c. The stereophonic subcarrier shall be the second harmonic of the pilot subcarrier and shall cross the time axis with a positive slope simultaneously with each crossing of time axis by the pilot subcarrier.
d. Amplitude modulation of the stereophonic subcarrier shall be used.
e. The stereophonic subcarrier shall be suppressed to a level less than one percent modulation of the main carrier.
f. The stereophonic subcarrier shall be capable of accepting audio frequency from 50 to 15,000 Hz.
g. The modulation signal for the stereophonic subcarrier shall be equal to the difference of the left and right signals.
h. The pre-emphasis characteristics of the stereophonic subchannel shall be identical with those of the main channel with respect to phase and amplitude at all frequencies.
i. The sum of the side bands resulting from amplitude modulation of the stereophonic subcarrier shall not cause a peak deviation of the main carrier in excess of 45 percent of total modulation (excluding SCA subcarriers) when only a left (or right) signal exists; simultaneously in the main channel, the deviation when only a left (or right) signal exists shall not exceed 45 percent of total modulation (excluding SCA subcarriers).
j. The maximum modulation of the main carrier by all SCA subcarrier be limited to 10 percent.
k. At the instant when only a positive left signals applied, the main channel modulation shall cause an upward deviation of the main carrier frequency; and the stereophonic subcarrier and its sidebands signal shall cross the time axis simultaneously and in the same direction.
l. The ratio of peak main channel deviation to peak stereophonic subchannel deviation, when only a steady state left (or right) signal exists, shall be within plus or minus 3.5 percent of unity for all levels of this signal and all frequency from 50 to 15,000 Hertz.
and the stereophonic subcarrier sidebands envelope, when only steady state left (or right) signal exists, shall exceed plus or minus 3 degrees for audio modulating frequencies from 50 to 15,000 Hz.
Note: If the stereophonic separation between left and right stereophonic channel is better than 29.7 decibels and audio modulating frequencies between 50 to 15,000 Hz it will be assumed that (l) and (m) of this section have been complied with.
n. Cross-talk into the main channel caused by a signal in the main stereophonic subchannel shall be attenuated at least 40 decibels below 90 percent modulation.
o. Cross-talk into the stereophonic subchannel caused by a signal in the main channel shall be attenuated at least 40 decibels below 90 percent modulation.
p. For required transmitter performance the maximum modulation to be employed is 90 percent (excluding pilot subcarrier) rather than 100 percent. q. For electrical performance standard of the transmitter and associated equipment, 100 percent modulation is referred to include the pilot subcarrier.
5.4 Subsidiary Communications Authorization (SCA)
5.4.1 Permissible uses of the SCA must fall within one or both of the following Categories
a. Transmission of programs which are of a broadcast nature, but which are of interest primarily to limited segments of the public wishing to subscribe thereto. Illustrative services include: background music stereocasting, detailed weather forecasting, special time signal; and other material of broadcast nature expressly designed and intended for business, professional, educational, religious, trade, labor, agriculture, or other groups engaged in any lawful activity.
b. Transmission of signals which are directly related to the operation of FM broadcast station; for example: relaying of broadcast material to other FM and standard AM broadcast stations; remote cueing and other circuits; remote control telemetering functions associated with authorized STL operation, and similar uses.
5.4.2 An application for SCA shall specify the particular nature and purpose of the proposed use. If visual transmission of program material is contemplated, the application shall include certain technical information concerning the visuals system, on which the Authority shall rely in issuing an SCA. If any significant change is subsequently made in the system, revised information shall be submitted. The technical information to be submitted is as follows:
a. A full description of the visual transmission system.
b. A block diagram of the system, as installed in the station, with all components including filters, identified as to make and type. Response curves of all composite filters shall be furnished.
5.4.3 SCA operations may be conducted without restriction as to time, so long as the main channel is programmed simultaneously.
5.4.4 Nature of the SCA
a. The SCA is of a subsidiary or secondary nature shall not exist apart from FM license or permit. No transfer or assignment of it shall be made separate from the FM broadcast license and failure to transfer the SCA with the FM license renders the SCA void. Any assignment or transfer of an SCA shall, if desired,be requested as part of the main station’s transfer or assignment application.
The licensee or permit must seek renewal of FM license or permit; failure to renew the latter automatically terminates the SCA.
b. The grant or renewal of an FM license or permit shall not be furthered or promoted by the proposed or past operation under an SCA; the license must
establish that this broadcast operation is in the public interest wholly apart from the SCA activities.
5.4.5 Multiplex Operations Engineering Standards
a. Frequency modulation of SCA subcarriers shall be used.
b. The instantaneous frequency of SCA subcarriers shall at all times be within the range 20 to 75 kHz; Provided, however, that when the station is engaged in stereophonic broadcasting, the instantaneous frequency of SCA subcarrier shall at all times be within the range 53 to75 kHz.
c. The arithmetic sum of the modulation of the main carrier by SCA subcarriers shall not exceed 30 percent: Provided, however, that when the station is engaged in stereophonic broadcasting, the arithmetic sum of the main carrier by the SCA subcarrier shall not exceed 10 percent.
d. The total modulation of the main carrier, including SCA subcarriers, shall meet the requirements of 6.2.2.
e. Frequency modulation of the main carrier caused by the SCA subcarrier operation shall, in the frequency range 90 to 15,000 Hz, be at least 60 dB below 100 percent modulation: Provided, however, that when thestation is engaged in stereophonic broadcasting, frequency modulation of the main carrier by the SCA subcarrier operation shall, in the frequency range 50 to 53,000 Hz, be at least 60 dB below 100 percent modulation.
f. The center frequency of each SCA subcarrier shall be kept at all times within 500 hertz of the authorized frequency.
5.4.6 Facsimile engineering standards
The following standards apply to facsimile broadcasting under SCA operations.
a. Rectilinear scanning shall be employed, with scanning spot progressing from left to right and scanned lines progressing from top to bottom of the subject copy.
b. The standard index of cooperation shall be 984.
c. The number of scanning lines per minute shall be 360.
d. The line-use ratio shall be 7/8, or 315 degrees of the full scanning cycle. e. The 1/8 cycle or 45 degrees not included in the available scanning line shall be divided into 3 equal parts, the first 15 degrees being used for transmission at approximately white level, the second 15 degrees for transmission at approximately black level, and the third 15 degrees for transmission at approximately white level.
f. An interval of not more than12 seconds shall be available between two pages of subject copy, for the transmission of a page-separation signal and/or other services.
g. Amplitude or (frequency-shift) modulation of the subcarrier shall be used. h. Subcarrier modulation shall normally vary approximately linearly with the optical density of the subject copy.
i. Negative modulation shall be used, i.e., for amplitude modulation of subcarrier, maximum subcarrier amplitude and maximum radio frequency swing on black; for frequency modulation of subcarrier, highest instantaneous frequency of subcarrier on black.
j. Subcarrier noise level shall be maintained at least 30 dB below maximum (black) picture modulation level, at the radio transmitter input.
k. The facsimile subcarrier transmission shall be conducted in the frequency range between 22 and 28 kHz. Should amplitude modulation of the carrier be employed the subcarrrier frequency shall be 25 kHz with sidebands extending not more than 3 kHz in either direction from the subcarrier frequency. Should frequency modulation of the subcarrier be employed the total swing at the subcarrier shall be within the range from 22 to 28 kHz, with 22 kHz corresponding to white and 20 kHz corresponding to black on the transmitted copy. In multiplex operation, the modulation of the FM carrier by the modulated subcarrier shall not exceed 5 percent. In simplex operation , the modulation of the FM carrier by the modulated subcarrier shall not exceed 30 percent.
i. During periods of multiplex facsimile transmission, frequency modulation of the FM carrier cause by the aural signals shall, in the frequency range from 20 to 30 kHz, be at least 60 db below 100 percent modulation. Frequency modulation of the FM carrier caused by the facsimile shall, in the frequency range from 50 to 15,000 Hertz, be at least 60 dB below 100 percent modulation.
5.5 Studio, Equipment and Allied facilities
5.5.1 The studio being the recognized source of program materials and other forms of intelligence of various kinds and content, must be properly equipped to faithfully respond to these impressions and produce the same to the highest degree possible, up to the turnover point which is the transmitter input. 5.5.2 Studio location and Layout
a. Each shall be associated with a control room for which the operational area of the studio may viewed with. However, when the studio and the control rooms are integrated into one, an announcer shall perform simple panel type functions like level adjustments and switching during his/her board hours.
b. Studios and control rooms shall be constructed that they are adequately insulated from source of extraneous noise and vibration, and the acoustic treatment of such studio and control rooms shall be in accordance with good engineering practice.
5.6 Emergency Equipment & Facilities 5.6.1 Alternate Main Transmitter
a. The regular and the optional main transmitter shall be located in a single place.
b. The external effects from both regular and main transmitters shall substaintially be the same as to frequency and stability.
5.6.2 Auxiliary Transmitter
