FM30/FM150/FM300 Broadcast Transmitter User's Manual ©2007 Crown Broadcast, a division of International Radio and Electronics Corporation 25166 Leer Drive, Elkhart, Indiana, 46514-5425 U.S.A.
Revision Control Revision Initial Release Print Date March 2007 Important Notices ©2007, Crown Broadcast, a division of International Radio and Electronics Corporation. Portions of this document were originally copyrighted by Michael P. Axman in 1994. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form by any means without the written permission of International Radio and Electronics, Inc.
Contents Section 1– Getting Acquainted 1-1 1.1 1.2 1.2.1 1.2.2 1.2.3 1.2.4 1.2.5 1.2.6 1.2.7 1.3 1.4 1.5 1.5.1 1.5.2 1.5.3 1-2 1-3 1-4 1-4 1-4 1-4 1-5 1-6 1-6 1-7 1-9 1-10 1-10 1-10 1-10 Your Transmitter Applications and Options Stand Alone Backup Booster Exciter Translator Satellator Nearcasting Transmitter/Exciter Specifications Receiver Specifications Safety Considerations Dangers Warnings Cautions Section 2– Installation 2-1 2.1 2.2 2.2.1 2.2.2 2.2.3 2.3 2.3.1 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.
Section 3-Operation 3-1 3.1 3.2 3.2.1 3.2.2 3.2.3 3.3 3.3.1 3.3.2 3.3.3 3.4 3.5 3.6 3.7 3.8 3.9 Initial Power-up Procedures Power Switches DC Breaker Power Switch Carrier Switch Front Panel Bar-Dot Displays Audio Processor Input Highband and Wideband Display Modulation Display Input Gain Switches Processing Control Stereo-Mono Switch RF Output Control Digital Multimeter Fault Indicators 3-2 3-4 3-4 3-4 3-4 3-5 3-5 3-5 3-5 3-6 3-6 3-6 3-7 3-7 3-8 Section 4-Principals of Operation 4-1 4.1 4.2 4.3 4.
Section 5-Adjustments and Tests 5-1 5.1 5.1.1 5.1.2 5.2 5.2.1 5.2.2 5-2 5-2 5-2 5-2 5-2 5-2 5-3 5-4 5-4 5-4 5-4 5-4 5-4 5-5 5-5 5-5 5-5 5-5 5-6 5-6 5-6 5-6 5-7 5-7 5-7 5-7 5-8 5-8 5-8 5-8 5-9 5-9 5-9 5-9 5-9 5-9 5-10 5-10 5-10 5-10 Audio Processor Adjustments Pre-Emphasis Selection Pre-Emphasis Adjustment Stereo Generator Adjustments Separation Composite Output Using a Modulation Monitor 5.2.3 19kHz Level 5.2.4 19kHz Phase 5.3 Frequency Synthesizer Adjustments 5.3.1 Frequency (Channel) Selection 5.3.
Section 6-Reference Drawings 6-1 6.1 6.2 Views Board Layouts and Schematics 6-2 6-4 Section 7-Service and Support 7-1 7.1 7.2 7.
Section 1—Getting Acquainted This section provides a general description of the FM30, FM150, and FM300 transmitters and introduces you to safety conventions used within this document. Review this material before installing or operating the transmitter.
1.1 Your Transmitter The FM30, FM150, and FM300 are members of a family of FM stereo broadcast transmitters. Crown transmitters are known for their integration, ease-of-use, and reliability. The integration is most apparent in the standard transmitter configuration which incorporates audio processing, stereo generation, and RF amplification without compromised signal quality. A single Crown transmitter can replace several pieces of equipment in a traditional system.
1.2 Applications and Options Crown transmitters are designed for versatility in applications. They have been used as stand-alone and backup transmitters and in booster, translator, satellator, and nearcast applications. The following discussion describes these applications further. Model numbers describe the configuration of the product (which has to do with its intended purpose) and the RF output power which you can expect. The number portion of each name represents the maximum RF output power.
1.2.1 Stand-Alone In the standard configuration, the FM30, FM150, and FM300 are ideal stand-alone transmitters. When you add an audio source (monaural, L/R stereo, or composite signal), an antenna, and AC or DC power, the transmitter becomes a complete FM stereo broadcast station, capable of serving a community. As stand-alone transmitters, Crown units often replace multiple pieces of equipment in a traditional setup (exciter, audio processor, RF amplifier). 1.2.
1.2.4 Translator A receiver configuration (FM150R, for example) replaces the audio processor/stereo generator board with a receiver module. This added feature makes the FM30, FM150, and FM300 ideal for translator service in terrestrial-fed networks. These networks represent a popular and effective way to increase your broadcasting coverage. Translators, acting as repeater emitters, are necessary links in this chain of events.
1.2.5 Satellator One additional option is available for all configurations—an FSK Identifier (FSK IDer). This added feature enables the FM30, FM150, and FM300 to transmit its call sign or operating frequency in a Morse code style. This option is intended for use in satellite-fed networks. Transmitters equipped in this fashion are often known as "satellators.
1.3 Transmitter/Exciter Specifications Frequency Range 87.9 MHz–107.9 MHz (76 MHz–90 MHz optionally available) RF Power Output (VSWR 1.
Subcarrier Suppression 50dB below ±75 kHz deviation FM S/N Ratio (FM noise) Complete Transmitter Better than –60dB Exciter only Better than –70dB AM S/N Ratio Asynchronous and synchronous noise better than FCC requirements RF Bandwidth ±120 kHz, better than –35 dB ±240 kHz, better than –45 dB RF Spurious Products Better than –70dB Operating Environment Temperature (0°C to 50°C) Humidity (0 to 80% at 20°C) Maximum Altitude (3,000 Meters; 9834 Feet AC Power 100,120, 220, or 240 volts +10%/15%);
Note: We set voltage and ampere requirements to assist you in designing your system. Depending on your operating frequency, actual requirements for maximum voltage and current readings are 10–15% lower than stated. Regulatory Type notified FCC parts 73 and 74 Meets FCC, DOC, and CCIR requirements Dimensions 13.5 x 41.9 x 44.5 cm 5.25 x 16.5 x 17.5 inches Weight FM30 10.5 kg (23 lbs) 13.6 kg (30 lbs) shipping weight FM150 11.4 kg (25 lbs) 14.5 kg (32 lbs) shipping weight FM300 16.8 kg (37 lbs) 20.
1.4 Receiver Specifications Monaural Sensitivity (demodulated, de-emphasized) 3.5 µ V for signal-to-noise > 50 dB Stereo Sensitivity (19–kHz pilot frequency added) 31 µ V for signal-to-noise > 50 dB Connector Standard type N, 50 Ω Shipping Weight 1 lb 1.5 Safety Considerations Crown Broadcast assumes the responsibility for providing you with a safe product and safety guidelines during its use.
Section 2—Installation This section provides important guidelines for installing your transmitter. Review this information carefully for proper installation.
2.1 Operating Environment You can install the FM transmitter in a standard component rack or on a suitable surface such as a bench or desk. In any case, the area should be as clean and well ventilated as possible. Always allow for at least 2 cm of clearance under the unit for ventilation. If you set the transmitter on a flat surface, install spacers on the bottom cover plate. If you install the transmitter in a rack, provide adequate clearance above and below.
Illustration 2–1 Removing the Power Connector Cover Illustration 2–2 Selecting an AC Line Voltage Installation 2-3
2.2.2 Fuses The fuse holders are located in the power connector assembly just below the voltage selector. Illustration 2–3 Fuse Holder For 100 to 120 VAC operation, use the fuse installed at the factory. For 220 to 240 VAC operation, use the slow-blow fuse located in a hardware kit within the transmitter packaging. Consult the following table: Transmitter Input Power Fuse FM30 100–120 V 220–240 V 3A 1.5 A FM150 100–120 V 220–240 V 6.3 A 4A FM300 100–120 V 220–240 V 12.5 A 6.
2.2.3 Battery Power Your transmitter can operate on a DC power source (such as 4 or 5, 12–volt deep cycle batteries connected in series). The FM30 requires 28 volts DC for full output power, while the FM150 requires 48 volts, and FM300 requires 72 volts for full output power. Connect the batteries to the red (+) and black (–) battery input binding posts on the rear panel. 2–5 Illustration DC Input Terminals 2.3 Frequency (Channel) Selection Your transmitter is capable of operating between 87.9 and 107.
2. Use small flat blade screwdriver or another suitable device to rotate the switches to the desired setting. (The selected number will appear directly above the white indicator dot on each switch.) See examples of selected frequencies in the illustration below. 3. To change the operating band from 87.9-107.9MHz to 76-90MHz or vice versa, or to adjust the modulation compensation pot, remove the top cover to gain access to these features. See illustrations 2-6 and 2-10.
2.3.1 Modulation Compensator The Modulation trim-potentiometer (see illustration 2–10) compensates for slight variations in deviation sensitivity with frequency. Set the trim-pot dial according to the following graph: Frequency of Operation (MHz) Modulation Compensation Pot Setting 108 106 104 102 100 98 97.1 96 94 92 90 88 86 84 82.4 82 80 78 76 0 10 15 25 35 40 45 55 60 70 75 80 80 80 70 65 55 30 0 Illustration 2–9 Modulation Compensator Settings These compensator settings are approximate.
2.4 Receiver Frequency Selection If you have a transmitter equipped with the receiver option, you will need to set the receiving or incoming frequency. 1. With the top cover removed, locate the receiver module and the two switches (labeled SW1 and SW2). Illustration 2–11 Receiver Module Switches 2. Use the adjacent chart to set the switches for the desired incoming frequency. 3. For frequencies in the Japan FM band, short pins 7&8 on J1 on the receiver card. 4.
Freq. 74-90 Freq. 88-108 MHz MHz 74.9 87.9 75.0 88.0 75.1 88.1 75.2 88.2 75.3 88.3 75.4 88.4 75.5 88.5 75.6 88.6 75.7 88.7 75.8 88.8 75.9 88.9 76.0 89.0 76.1 89.1 76.2 89.2 76.3 89.3 76.4 89.4 76.5 89.5 76.6 89.6 76.7 89.7 76.8 89.8 76.9 89.9 77.0 90.0 77.1 90.1 77.2 90.2 77.3 90.3 77.4 90.4 77.5 90.5 77.6 90.6 77.7 90.7 77.8 90.8 77.9 90.9 78.0 91.0 78.1 91.1 78.2 91.2 78.3 91.3 78.4 91.4 78.5 91.5 78.6 91.6 78.7 91.7 78.8 91.
Freq. 74-90 Freq. 88-108 MHz MHz 82.9 95.9 83.0 96.0 83.1 96.1 83.2 96.2 83.3 96.3 83.4 96.4 83.5 96.5 83.6 96.6 83.7 96.7 83.8 96.8 83.9 96.9 84.0 97.0 84.1 97.1 84.2 97.2 84.3 97.3 84.4 97.4 84.5 97.5 84.6 97.6 84.7 97.7 84.8 97.8 84.9 97.9 85.0 98.0 85.1 98.1 85.2 98.2 85.3 98.3 85.4 98.4 85.5 98.5 85.6 98.6 85.7 98.7 85.8 98.8 85.9 98.9 86.0 99.0 86.1 99.1 86.2 99.2 86.3 99.3 86.4 99.4 86.5 99.
Freq. 74-90 Freq. 88-108 MHz MHz X 103.3 X 103.4 X 103.5 X 103.6 X 103.7 X 103.8 X 103.9 X 104.0 X 104.1 X 104.2 X 104.3 X 104.4 X 104.5 X 104.6 X 104.7 X 104.8 X 104.9 X 105.0 X 105.1 X 105.2 X 105.3 X 105.4 X 105.5 X 105.6 X 105.7 X 105.8 X 105.9 X 106.0 X 106.1 X 106.2 X 106.3 X 106.4 X 106.5 X 106.6 X 106.7 X 106.8 X 106.9 SW1 SW2 4 C 4 C 4 C 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D 5 D D E E F F 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 A A B B C C D D E E F Freq. 74-90 Freq.
2.5 RF Connections Connect the RF load, an antenna or the input of an external power amplifier, to the type-N, RF output connector on the rear panel. VSWR should be 1.5:1 or better. The RF monitor is intended primarily for a modulation monitor connection. Information gained through this connection can supplement that which is available on the transmitter front panel displays. If your transmitter is equipped with the receiver option, connect the incoming RF to the RF IN connector.
2.6 Audio Input Connections Attach audio inputs to the Left and Right XLR connectors on the rear panel. (The Left channel audio is used on Mono.) Pin 1 of the XLR connector goes to chassis ground. Pins 2 and 3 represent a balanced differential input with an impedance of about 50 kΩ . They may be connected to balanced or unbalanced left and right program sources. The audio input cables should be shielded pairs, whether the source is balanced or unbalanced.
2.7 SCA Input Connections You can connect external SCA generators to the SCA In connectors (BNC-type) on the rear panel. The inputs are intended for the 60 kHz to 99 kHz range, but a lower frequency may be used if the transmitter is operated in Mono mode. (The 23 to 53 kHz band is used for stereo transmission.) For 7.5 kHz deviation (10% modulation), input of approximately 3.5–volts (peak-to-peak) is required. Illustration 2–15 SCA Input Connectors 2.
Illustration 2–16 Composite In and Audio Monitor Connections 2.9 Audio Monitor Connections Processed, de-emphasized samples of the left and right audio inputs to the stereo generator are available at the Monitor jacks on the rear panel. The signals are suitable for feeding a studio monitor and for doing audio testing. De-emphasis is normally set for 75 µsec; set to 50 µsec by moving jumpers, HD201 and HD202, on the Audio Processor/Stereo Generator board. 2.
2.11 Program Input Fault Time-out You can enable an automatic turn-off of the carrier in the event of program failure. To enable this option, see illustration 2-18 on page 2-16. The time between program failure and carrier turn-off is set by a jumper (JP1) on the voltage regulator board (see page 6–14 for board location).
Pin Number Function 1. Ground 2. FMV Control 3. Composite Out (sample of stereo generator output) 4. FSK In (Normally high; pull low to shift carrier frequency approximately 7.5 KHz. Connect to open collector or relay contacts of user-supplied FSK keyer.) 5. /Auto Carrier Off (Pull low to enable automatic turnoff of carrier with program failure.) 6. Meter Battery (Unregulated DC voltage; 5 VDC=50 VDC) 7. Meter RF Watts (1 VDC = 100 Watts) 8. Meter PA Volts (5 VDC = 50VDC) 9.
Notes: 2-18 FM30/FM150/FM300 User’s Manual
Section 3—Operation This section provides general operating parameters of your transmitter and a detailed description of its front panel display.
3.1 Initial Power-up Procedures These steps summarize the operating procedures you should use for the initial operation of the transmitter. More detailed information follows. 1. Turn on the DC breaker. Illustration 3–1 DC Breaker 2. Turn on the main power switch.
3. Verify the following: A. The bottom cooling fan runs continuously. B. The Lock Fault indicator flashes for approximately 5 seconds, then goes off. 4. Set the Input Gain switches for mid-scale wideband gain reduction on an average program level (see section 3.4). 5. Set the Processing control (see section 3.5; normal setting is “50”). 6. Set the Stereo-Mono switch to Stereo (see section 3.6). 7. Turn on the Carrier switch. 8. Check the following parameters on the front panel multimeter: A.
3.2 Power Switches 3.2.1 DC Breaker The DC breaker, on the rear panel, must be on (up) for transmitter operation, even when using AC power. Electrically, the DC breaker is located immediately after diodes which isolate the DC and AC power supplies. 3.2.2 Power Switch The main on/off power switch controls both the 120/240 VAC and the DC battery power input. 3.2.
3.3 Front Panel Bar-Dot Displays Bar-dot LEDs show audio input levels, wideband and highband audio gain control, and modulation percentage. Resolution for the gain control and modulation displays is increased over a conventional bar-graph display using dither enhancement which modulates the brightness of the LED to give the effect of a fade from dot to dot. (See section 4.7.) 3.3.
3.4 Input Gain Switches The “+6 dB” and “+12 dB” slide switches set audio input sensitivity according to the following table. Normal Input Sensitivity +6dB +12dB +10dBm Down Down +4dBm Up Down -2dBm Down Up -8dBm Up Up Switches Illustration 3–4 Input Gain Switches Find, experimentally, the combination of Input Gain switch settings that will bring the Wideband gain-reduction indicator to mid scale for “normal” level program material.
3.7 RF Output Control Set this control for the desired output power level. Preferably, set the power with an external RF wattmeter connected in the coaxial line to the antenna. You may also use the RF power reading on the digital multimeter. The control sets the RF output voltage. Actual RF output power varies as the approximate square of the relative setting of the control. For example, a setting of “50” is approximately 1/4 full power. 3.
PA DC Volts—Supply voltage of the RF power amplifier. PA DC Amps—Transistor drain current for the RF power amplifier. PA DC Temperature—Temperature of the RF power amplifier heatsink in degrees C. Supply DC Volts—Unregulated DC voltage at the input of the voltage regulators. For battery operation, this reading is the battery voltage minus a diode drop. Voltmeter—Reads the voltage at a test point located on the front edge of the motherboard.
Section 4—Principles of Operation This section discusses the circuit principles upon which the transmitter functions. This information is not needed for day-to-day operation of the transmitter but may be useful for advanced users and service personnel.
4.1 Part Numbering As this section refers to individual components, you should be familiar with the part numbering scheme used. The circuit boards and component placement drawings use designators such as “R1”, “R2”, and “C1.” These same designators are used throughout the transmitter on several different circuit boards and component placement drawings. When referencing a particular component it is necessary to also reference the circuit board that it is associated with.
4.2 Audio Processor/Stereo Generator Circuit Board The audio board provides the control functions of audio processing-compression, limiting, and expansion, as well as stereo phase-error detection, pre-emphasis and generation of the composite stereo signal. Illustration 6-4 and accompanying schematic may be useful to you during this discussion. The overall schematic for the audio board is divided into two sheets; one each for the processor and stereo generator sections of the board.
Q1 (Q2) is a recover/expansion gate with a threshold about 18 dB below the normal program level. The amount of short-term expansion and time for gain recovery is controlled by the PROCESSING control, located on the front panel display board. (See section 3.5.) Audio components above 15,200 Hz are greatly attenuated by eighth-order switchedcapacitor elliptical filter, U5 (U11). The filter cut-off frequency is determined by a 1.
Processed, pre-emphasized left and right audio is passed through third-order lowpass filters comprised of U202A (203A) and associated circuitry. The filters decrease the level of audio products below 30 Hz. This low-frequency roll off is necessary to prevent disturbance to the phase-lock loop in the RF frequency synthesizer by extremely low-frequency audio components. (See caution at section 2.8.) U204 is a precision, four-quadrant, analog multiplier.
4.3 RF Exciter Circuit This circuit is also known as the Frequency Synthesizer. The Frequency Synthesizer part of the motherboard is no longer a separate module as was the case on older transmitters.The entire component side of the motherboard is a ground plane. Frequency selector switches located on the front panel of the transmitter establish the operating frequency. The VCO (voltage-controlled oscillator) circuitry is inside an aluminum case.
4.5 Metering Circuit The ALC and metering circuitry is on the motherboard (see Illustration 6–6). This circuit processes information for the RF and DC metering, and produces ALC (RF level-control) bias. It also provides reference and input voltages for the digital panel meter, voltages for remote metering, fan control, and drive for the front-panel fault indicators. Illustration 6–6 and accompanying schematics complement this discussion.
4.6 Motherboard The motherboard is the large board in the upper chassis interconnecting the audio processor/stereo generator board or the optional receiver module or the Omnia digital audio processor to the RF exciter and metering circuits. The motherboard provides the interconnections for this boards, eliminating the need for a wiring harness, and provides input/output filtering.
Motherboard Jumper Configuration Chart 4.6.
4.7 Display Circuit Board The front-panel LEDs, the numeric display, the slide switches, and the processing and RF level controls are mounted on the display circuit board. To access the component side of the board, remove the front panel by removing 12 screws. The board contains circuits for the digital panel meter, modulation peak detector, and LED display drivers, as well as indicators and switches mentioned above. Illustration 6–9 and accompanying schematic complement this discussion.
4.8 Voltage Regulator Circuit Board The voltage regulator board is the longer of two boards mounted under the chassis toward the front of the unit. It has switch-mode voltage regulators to provide +12, –12, and 20 volts. It also contains the program detection and automatic carrier control circuits. Illustration 6–10 and accompanying schematic complement this discussion. U3E and U3F convert a 38–kHz sine wave from the stereo generator into a synchronization pulse.
4.9 Power Regulator Circuit Board The power regulator board is the shorter of two boards mounted under the chassis toward the front of the unit. The board has the isolating diode for the battery input, the switch-mode voltage regulator for the RF power amplifier, and circuitry for PA supply current metering. Illustration 6–10 and accompanying schematic complement this discussion.
4.11 RF Driver (FM150/FM300) The RF Driver assembly is mounted on a 100 mm x 100 mm plate in the under side of the chassis. Illustration 6-14 and accompanying schematic complement this discussion. The driver amplifies the approximate 20 milliwatts from the frequency synthesizer to about 8 watts to drive the RF power amplifier. An MHW6342T hybrid, high-gain, wideband amplifier, operating at about 20 volts, provides about one watt of drive to a single BLF245 MOSFET amplifier.
4.13 Chassis The AC power supply components, as well as the bridge rectifier and main filter capacitor, are mounted on the chassis. Switching in the power-entry module configures the power transformer for 100, 120, 220, or 240 VAC; see section 2.2 for switching and fuse information. A terminal strip with MOV voltage-surge suppressors and in-rush current limiters is mounted on the chassis between the power entry module and the toroidal power transformer.
4.15 Receiver Circuit Board Option This option allows the transmitter to be used as a translator. The receiver board receives terrestrially fed RF signal and converts it to composite audio which is then fed into the exciter board. Microprocessor controlled phase lock loop technology ensures the received frequency will not drift, and multiple IF stages ensure high adjacent channel rejection. Refer to illustrations 4–6, 6–16 and its schematic for the following discussion.
When a stereo signal is present, LED 3 illuminates which indicates that left and right audio is available. Then the stereo signals go to gain stages and out to the RCA jacks on the back of the cabinet. These can be used for off-air monitoring of the audio signal. Incoming frequency can be monitored from the frequency monitor BNC jack on the back. The stereo buffer, stereo decoder, and gain stages and have no effect on the signal that goes through the transmitter. The power supply is fairly straight forward.
Section 5—Adjustments and Tests This section describes procedures for (1) advanced users who may be interested in customizing or optimizing the performance of the transmitter and (2) service personnel who want to return the transmitter to operational status following a maintenance procedure.
5.1 Audio Processor Adjustments 5.1.1 Pre-Emphasis Selection Select the pre-emphasis curve (75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the appropriate pins of header HD1 on the audio processor/stereo generator board. (See section 2.9.) If you change the pre-emphasis, change the de-emphasis jumpers, HD201 and HD202 on the audio processor/stereo generator board, to match. (See section 2.8.) 5.1.
5.2.2 Composite Output You can make adjustments to the composite output in the following manner: Using a Modulation Monitor 1. Set the Stereo-Mono switch to Mono. 2. Check that the setting of the Modulation compensation control (see illustration 2–9) on the RF Exciter circuit , falls within the range specified for the frequency of operation. (See section 2.3.1.) 3. Feed a sine wave signal of about 2.
5.3.2 Modulation Compensator Refer to section 2.3.1 5.3.3 Frequency Measurement and Adjustment Next to the 10.24–MHz VCXO in the RF Exciter circuit on the motherboard, is a 50K potentiometer (R101). Use R101 to set the frequency of the 10.24–MHz VCXO while observing the output frequency of the synthesizer. Use one of two methods for checking frequency: 1. Use an FM frequency monitor. 2. Couple a frequency counter of known accuracy to the output of the synthesizer and observe the operating frequency. 5.3.
5.4.3 SWR Calibrate When the Carrier switch is off, or the RF power is less than about 5 watts, the SWR circuit automatically switches to a calibrate-check mode. (See section 4.5 for more information.) Set the digital panel meter to read SWR. With the Carrier switch off, set the SWR CAL trim pot (R66) to read 1.03. 5.4.4 PA Current Limit Since it may not be practical to increase the PA current to set the PA Current Limit control, you may use this indirect method.
5.7 Voltage Regulator Adjustments JP1, a 10–pin header on the Voltage Regulator board, sets the time between program failure and carrier turnoff. Pins 1 and 2 are the two pins closest to the edge of the board. The times are approximate. Sections 2.11, 2.12, and 4.8 contain further information. 1. Short pins 1 and 2 for a 30–second delay. 2. Short pins 3 and 4 for a 2–minute delay. 3. Short pins 5 and 6 for a 4–minute delay. 4. Short pins 7 and 8 for an 8–minute delay.
5.9 Performance Verification Measure the following parameters to receive a comprehensive characterization of transmitter performance: • Carrier frequency • RF output power • RF bandwidth and RF harmonics (see section 5.
5.10 Carrier Frequency Carrier frequency is measured at the output frequency with a frequency monitor or suitable frequency counter. To adjust frequency, see section 5.3.3. (FCC tolerance +/– 2000 Hz per FCC Part 73.1540 and 73.1545.) 5.11 Output Power The output power reading on the front panel display should be 90–105% of the actual value. For a more precise measurement, use a watt meter in the RF output line. See sections 5.4.1 and 5.4.2 for setting power. 5.
5.15 Audio Distortion Make distortion measurements from the de-emphasized output of an FM modulation monitor. Make audio distortion measurements for left and right channels at frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See sections 5.9.1 and 5.9.2. 5.16 Modulation Percentage While feeding an audio signal into the left channel only, confirm that the total modulation percentage remains constant when switching between Mono and Stereo.
5.20 38–kHz Subcarrier Suppression With no modulation, but in the Stereo mode, the 38–kHz subcarrier, as indicated on an FM modulation monitor, should be down at least 40 dB. 5.21 Additional Checks In addition to the tests and adjustments mentioned in this section, the following checks ensure a complete performance appraisal of the transmitter: 1. Perform a physical inspection, looking for visible damage and checking that the chassis hardware and circuit boards are secure. 2.
Section 6—Reference Drawings The illustrations in this section may be useful for making adjustments, taking measurements, troubleshooting, or understanding the circuitry of your transmitter.
6.
Metering Circuit Audio Processor Section RF Low Pass Filter & Reflectometer Stereo Generator Section RF Exciter Circuit DC Input RF output Power Amplifier (FM150/M300 Only) Illustration 6-3 Chassis Top View Voltage Regulator Power Regulator RF Pre-driver/ Amplifier Filter Capacitor AC Power Transformer Bridge Rectifier AC Power Entry Illustration 6-4 Chassis Bottom View Adjustments and Tests 6-3
Notes: 6-4 FM30/FM150/FM300 User’s Manual
6.
Board Layouts and Schematics DWG. NO. 3 REV. 4 5 GAIN R9-14 --------------------------0dB OPEN +6dB 50.5K +12dB 16.8K +18dB 7.21K C5 6 7 R7 R12 49.9 R6 2.00K D2 1N6263 R13 49.9 49.9 R5 R14 5.1K R17 COMP1* Vout INV A NC 1uF 9 R22 8 24.9K C6A 1 +5V 10 9 A B 10uF DS1 DS2 1N5818 1N5818 C29 10uF 510 R68 1.0K 8 6 5 4 3 2 R84 D25 10M D26 R88 POLY D13 4 1 R79 TL072 10K 6 5 4 POLY (C8687-3) U12 THAT2180 TL072 499 +12V 1 IN R91 R92 49.9K 49.
DWG. NO. 1 2 3 REV. 4 5 6 7 H 0 12 11 6 H OPEN C203 100pF R230 7 2 1 RG1 8 3 RG2 Composite Spec. (Turkey): 30Hz - 53KHz +/- 0.2 dBr 53KHz - 76KHz +/- 0.4dBr U201 R206 6 AD622 3.9K 4 5 R205 OPEN R204 49.9K R201 1K EXT IN+ 10 +12V C202 100pF EXTERNAL COMPOSITE INPUT 5 0 R203 1K EXT IN- 9 C204 R217 SCA IN 8 -12V R202 49.9K C201 100pF G G R207 150K 2 C206 3 +12V -12V -12V +7V +7V -7V -7V F .047uF .
Board Layouts and Schematics Illustration 6-6 Motherboard 6-8 Adjustments and Tests FM30/150/300 User’s Manual
DWG. NO. 1 2 J16 FAN A REV. 5 6 7 8 9 J14 -12V +12V RF OUT ALC COMPOSITE1 LOCK /LOCK RF_LVL LOC/REMOTE GND FSK IN -12V NC Vin NC TEMP Vout GND TRM 8 7 2 6 3 TL072 1 U3A -12V OPEN 100 C28 1.0 TL072 7 U3B /LOCK RF_LVL LOC/REMOTE ALC G COMPOSITE1 LOCK -12V RF OUT E2 E3 E4 J9 RF_LVL V+ TEMP GND 1 2 3 TEMP HEADER 3X1 C159 .001 PAI PAV N/C N/C /LOCK FAULT NC FSK IN NC C158 .001 NC J2 +5.
Board Layouts and Schematics 4 5 1.00V = 10VDC C119 .01 R161 100K 1% 1 U19A 3 D29 1N4148 R194 15K R195 10K 11 50mv per degree C. R164 1M 100K R169 10K R166 220K U20C -12V R181 240K METER PATEMP 3 R158 100K R135 100K 1% D33 1N4148 5 U22B R184 1K 7 ALC TL074 E R155 11K 1% 5 1 2 2 U23C Q7 1 2 3 4 C135 .01 TL074 8 7 6 5 Q6 1 2 3 4 1 R215 10K + R44 51.1K 10 TL074 U24C TL074 R207 3.3K R213 49.
1 2 3 4 5 DWG. NO. 6 REV. 201497F-SCH A 8 9 10 11 12 88-108 MHZ +8V +12V R81 150 +12V 2 1 A2 MAR-6 C79 .001 GND 12 C109 1 D19 1N4148 U13 OSC in 1 2 3 Fin 4 5 6 7 8 HEADER 10 C101 100pF 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 16 15 14 13 12 11 10 9 R105 100K 1% VDD R106 10 C103 C92 1 MC145170 11 10 U15F 74HC14 LOCK C75 .001 U15E 74HC14 C108 3900PF U14C 10 R114 100K 1% MC33284P MC33284P R111 100K 1% 8 13 U14D 12 14 C107 .001 POLY R80 15 TANT. C98 .
Board Layouts and Schematics 1 E . C . N. 2 3 REVISION HISTORY DESCRIPTION REV PRODUCTION RELEASE A 4 DATE DWN 03-08-07 DW APPROVALS CHK CM DW PE DP F F Illustration 6-7 FM Frequency Selection Board (Top-Side) 7 1 2 3 4 5 6 7 8 9 10 RP1 100K RPACK D 10 9 8 7 6 5 4 3 2 1 REV. J1 D1 1N4148 DWG. NO.
Illustration 6-9 FM Display Board FM30/FM150/FM300 User’s Manual 6-13
Board Layouts and Schematics 3 4 5 DWG. NO. 6 REV. Q43113-2F H 8 9 9 +12V 4 R1 68K L VU U1A D1 1N4148 R3 1K 1 6 5.00V 5 C2 1.
Illustration 6-10 FM Voltage Regulator FM30/FM150/FM300 User’s Manual 6-15
Board Layouts and Schematics 1 2 3 4 5 REV. DWG. NO. 6 8 9 10 11 REVISION HISTORY DESCRIPTION 12 APPROVALS CHK CM E . C . N. REV DATE DWN 475 AF REDRAWN ON IREC FORMAT. PWA & PWB NOW RoHS 9-14-06 DW DW DP 493 AG CORRECTED PWB TO CONNECT R29 2-19-07 DW DW PE DP R1 4.7K H CARR SW H U3C R2 10.0K /CARRIER OFF 5 6 74HC14 R33 4.7K D1 1N4148 +12V VDD R3 4.7K G U3A /AUTO CARRIER U3B 1 2 R4 10.0K 74HC14 R23 1.0K D2 1N4148 3 G +6V 4 VCC 74HC14 DZ1 1N4735 6.
Illustration 6-11 FM Power Regulator FM30/FM150/FM300 User’s Manual 6-17
Board Layouts and Schematics 1 2 3 4 5 ON CHASSIS E . C . N. ~ DC INPUT + C1001 0.015F 110V ~ REV 8 APPROVALS CHK CM DATE DWN 10-31-03 DW DW DP 01-29-04 DW DW DP 08-10-04 DW DW DP DW DW DP PRODUCTION RELEASE 274 B CORRECTED Z3 AND Z6 UNIT STATUS FOR M2 AND FM100 323 C SWAPPED Z1, Z2 TO MATCH PWB 475 D PWA & PWB NOW RoHS.
R19 Illustration 6-12 FM Power Amplifier FM150/FM300 FM30/FM150/FM300 User’s Manual 6-19
Board Layouts and Schematics 1 2 3 4 5 6 E . C . N. REV A 7 REVISION HISTORY DESCRIPTION PRODUCTION RELEASE 8 DATE DWN 02-20-07 DW APPROVALS CHK CM DW PE DP F F E C10 .01 R10 12K R11 10K L22 50NH 3 R12 5.6 R16 10, 1/8W LB01 R13 5.6 C13 .01 C12 .01 J01 BEAD BNC RECEPT Q01 SD2942 C16B 6.5-30pF G2 3W C01 .01 C16A 10PF R17 24, 3W G1 C14 .01 R14 5.6 C C25 55pF T21 D2 J02 BNC RECEPT. S T11S T1111P REV. 2 C11 .01 R19 200 C22 0.1 C21 .01 15K 1 DZ10 6.
Illustration 6-13 FM Low Pass Filter #2 FM30/FM150/FM300 User’s Manual 6-21
Board Layouts and Schematics 1 EP 2 3 4 5 6 E . C . N. 7 REVISION HISTORY DESCRIPTION REV REDRAWN J 8 DATE DWN 12-05-03 DW APPROVALS CHK CM PE DP F F E E C11 47pF NPO SHIELD C4 7.1pF C6 9.3pF C8 5.13pF R3 10 R2 73.2 REV. C2 1.35pF J1 RF IN RF OUT L4 87.5nH L5 77.9nH J2 BNC R4 10 D L1 OPEN C1A 10pF C17 3.5pF C1 15.4pF C3 40.9pF C5 38.9pF C7 37.7pF C9 14.1pF C10 2pF D1 R5 73.2 R6 1K 1N6263 FWD R9 1K REFL C19 47pF C1-C10 AND C17 ARE PWB COPPER AREAS C13 0.
Illustration 6-14 FM RF Driver FM30/FM150/FM300 User’s Manual 6-23
Board Layouts and Schematics 2 3 4 5 C23 REV DATE DWN M PRODUCTION RELEASE 12-10-03 DW DW DP 279 N XU1 WAS 200479-TERM-10 01-29-04 DW DW MH 316 O PWB CHG'D TO REV. C 06-14-04 DW DW DP 361 P PWB CHG'D TO REV. D 03-22-05 DW DW DP 475 Q PWA & PWB NOW RoHS. 07-28-06 DW DW DP OPEN XU1 MHW6342T C4 OPEN R18 C7 0.01 OPEN 0 D1 OPEN 1 2 3 4 5 6 7 8 9 D2 OPEN 3 2 1 R3 OPEN R6 OPEN C3 .
2 1 3 E . C . N. REV 160-A A 4 5 REVISION HISTORY DESCRIPTION PRODUCTION RELEASE 6 DATE DWN 02-19-02 DW APPROVALS CHK CM PE D D PAD PAD PAD B4 DWG. NO. PAD J1 BNC J2 1 2 3 4 5 6 B3 RF Illustration 6-15 FM Euroamp DC Input Feedthru (Top Side) PAD GND PAD PAD B2 GND FAN TEMP+ SENSE V1+ V2+ C HEADER 6 PAD PAD REV. PAD PAD PAD PAD PAD PAD PAD PAD C2 .01 C1 OPEN C3 .01 C4 .01 C5 .
Board Layouts and Schematics 1 2 3 4 5 DWG. NO. 6 201232-SCH REV. A 8 9 E . C . N. 10 11 REVISION HISTORY DESCRIPTION REV A PRODUCTION RELEASE 12 DATE DWN 04-04-05 DW APPROVALS CHK CM PE DP H H BATTERY IN CB1001 CIRCUIT BREAKER ON MOTHER BOARD G 9 7 5 3 1 x x x 1 2 3 4 5 6 10 8 6 4 2 VOLTAGE REGULATOR RF DRIVER HD702 PL1001 BNC RF IN RF OUT M1HD-S RF POWER AMP RF IN DRVR V+ DRVR V+ -12V PL1005 +12V 1 2 3 4 5 J4 FAN 6 5 4 3 2 1 F HD701 HEADER 6 HD703 HD4 6 C0ND.
Section 7—Service and Support We understand that you may need various levels of support or that the product could require servicing at some point in time. This section provides information for both of these scenarios.
7.1 Service The product warranty (see opposite page) outlines our responsibility for defective products. Before returning a product for repair or replacement (our choice), call our Customer Service department using the following telephone number: (866) 262-8917 Our Customer Service Representative will give you further instructions regarding the return of your product. Use the original shipping carton or a new one obtained from Crown.
Crown Broadcast Three Year Limited Product Warranty Summary Of Warranty Crown Broadcast IREC warrants its broadcast products to the ORIGINAL PURCHASER of a NEW Crown Broadcast product, for a period of three (3) years after shipment from Crown Broadcast. All products are warranted to be free of defects in materials and workmanship and meet or exceed all specifications published by Crown Broadcast. Product nameplate with serial number must be intact and not altered in any way.
The following lists describe the spare parts kit available for your transmitter. For the FM150 and FM300, use part number GFMSPARES. The following parts are included: Item Fuse, 4A Slo-blo 5mmX20mm Quantity 6 Fuse, 6.3A Slo-blo 5mmX20mm 5 Fuse, 12.5A Slo-blo 5mmX20mm 15A 100V N-CH MOSFET 130V RMS 200V PEAK 6500A ZENER 35A 400V Bridge Rectifier 5 2 Diode, BYV72E–150 20A 150V 2 2 1 MOS Gate Driver, 500V IR #IR2125 2 MOSFET, RF SD2942 Switching Regulator, 0.
Factory Service Instructions To obtain factory service, complete the bottom half of this page, include it with the unit, and ship to: International Radio and Electronics Corporation 25166 Leer Drive Elkhart, Indiana, U.S.A. 46514-5425 For units in warranty (within 3 years of purchase from any authorized Crown Dealer): We pay for ground UPS shipments from anywhere in the continental U.S. and Federal Express Second Day service from Hawaii and Alaska to the factory and back to you.
Appendix Transmitter Output Efficiency RF Power Output-FM 30 PADC Volts 27.9 PADC Amps 2.16 RF Power 34 Efficiency 56 26.2 2.09 32 58 24.7 2.02 30 60 22.5 1.91 26 60 20.2 1.77 22 62 17.0 1.56 17 64 14.1 1.34 14 74 12.6 1.22 10 65 10.5 1.04 7 64 8.8 .88 5 65 6.6 .65 3 70 5.4 .53 2 70 Power measurements were made at 97.1 MHz. Voltage and current measurements were taken from the unit’s built-in metering. The accuracy of the internal metering is better than 2%.
Transmitter Output Efficiency RF Power Output-FM 150 PADC Volts 34.3 32.8 28.4 23.1 16.4 9.4 PADC Amps 6.05 5.87 5.34 4.77 4.09 3.16 RF Power 165 150 113 75 38 15 Efficiency 79.5 77.9 74.5 68.1 56.7 50.5 Power measurements were made at 97.9 MHz. Voltage and current measurements were taken from the unit’s built-in metering. The accuracy of the internal metering is better than 2%. Return loss of the RF load was greater than –34 dB at test frequency . RF Power Output-FM 300 PADC Volts 48.5 46.3 40.2 33.
Notes: A-3 FM30/FM150/FM300 User’s Manual
Glossary The following pages define terms and abbreviations used throughout this manual.
AF Audio Frequency; the frequencies between 20 Hz and 20 kHz in the electromagnetic spectrum ALC Automatic Level Control AM Amplitude Modulation; the process of impressing information on a radio-frequency signal by varying its amplitude. Bandwidth The range of frequencies available for signaling. BCD Binary-Coded Decimal; a digital system that uses binary codes to represent decimal digits.
FET Field-Effect Transistor Frequency Synthesizer A circuit that generates precise frequency signals by means of a single crystal oscillator in conjunction with frequency dividers and multipliers. FM on Frequency Modulation; the process of impressing a radio signal by varying its frequency. FSK Frequency Shift Keying; an F technique for shifting the frequency of the main carrier at a Morse code rate. Used in the on-air identification of frequencies.
RF Radio Frequency; (1) A specific portion of the electromagnetic spectrum between audio-frequency and the infrared portion. (2) A frequency useful for radio transmission (roughly 10 kHz and 100,000 MHz). SCA Subsidiary Communications Authorization; see “subcarrier.” S/N Signal to Noise Spurious products Unintended signals present on the transmission output terminal.
Symbols 19–kHz level adjustment 5–3 phase adjustment 5–3 A AC.
D DC. See Power: input De-emphasis 2-15, 5-2, 5-7 jumpers 2-15 Delay program failure to carrier turnoff 2-16, 5-6 Dimensions 1-9 Display circuit description 4-10 front panel 3-2, 3-5, 3-7 modulation calibration 5-5 Distortion 1-7 audio 5-9 harmonic 4-5 E Emissions 5-8 Exciter.
operation 2-13, 3-6 Motherboard circuit description 4-8 Multimeter 3-7 front panel 3-3 Processing audio 1-2, 3-5 control 3-6 control setting 3-3 highband 3-5, 4-4 Program failure 2-16, 5-10 Program source 2-13, 3-6 N R M (continued) Mono Nearcast transmitter use 1-6 Networks satellite fed 1-6 terrestrial fed 1-5 Noise 1-8, 3-8 measurements 5-9 O Operating environment 1-8, 2-2 Options 1-3, 1-4, 1-6 Output power 1-7, 3-7 display 3-7 Output filter 4-14 P Part numbering 4-2 Parts spares 7-2 Performance
S (continued) Stand alone transmitter use 1-4 Stereo separation 1-7, 5-9 Stereo generator 1-2, 2-14 adjustments 5-2 bypassing 2-14 circuit description 4-4 circuit location 6-3 Subcarrier 5-10 38kHz 5-10 Suppression subcarrier 1-8 Switches carrier 3-3, 3-4, 5-5 input gain 3-5, 3-6 power 3-2, 3-4 receiver 2-8 stereo-mono 3-3, 3-6 SWR 3-7 calibrate 5-5 fault 3-8 Synchronization 4-11 Synthesizer, See RF exciter VSWR 1-2, 2-12 W Warranty 7-3 Weight 1-9 Wideband 3-5 X XLR connectors 2-13 T Temperature fau
