Related Manuals for Crown FM250G
Summary of Contents for Crown FM250G
- Page 1 FM250G Broadcast Transmitter User’s Manual ©2002 Crown Broadcast, a division of International Radio and Electronics, Inc. 25166 Leer Drive, Elkhart, Indiana, 46514-5425 U.S.A. (574) 262-8900...
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Page 2: Important Notices
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 Crown International, Inc. Printed in U.S.A. -
Page 3: Table Of Contents
2.10 Pre-emphasis Selection ................2-11 2.11 Processor Bypass Option ................2-11 2.12 Program Input Fault Time-out ..............2-12 2.13 Remote I/O Connector ................2-12 Section 3—Operation 3.1 FM250G Initial Power-up Procedures ............3–2 3.1.1 Power Switch ..................3–3 3.1.2 Carrier Switch..................3–3 3.2 Front Panel Bar-Dot Displays..............3–4 3.2.1... - Page 4 5.5 Motherboard Adjustments ................5–5 5.6 Display Modulation Calibration ..............5–5 5.7 Voltage Regulator Adjustments ..............5–5 5.8 Performance Verification ................5–6 5.8.1 Audio Proof-of-Performance Measurements.......... 5–6 5.8.2 De-emphasis Input Network..............5–6 5.9 Carrier Frequency ..................5–6 5.10 Output Power....................5–6 FM250G User’s Manual...
- Page 5 Rev A 5.11 RF Bandwidth and RF Harmonics ............... 5–7 5.12 Pilot Frequency ................... 5–7 5.13 Audio Frequency Response ................ 5–7 5.14 Audio Distortion..................5–7 5.15 Modulation Percentage ................5–7 5.16 FM and AM Noise ..................5–7 5.17 Stereo Separation ..................5–8 5.18 Crosstalk.....................
- Page 6 Rev A FM250G User’s Manual...
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Page 7: Section 1-Getting Acquainted
Rev A I NFORMATION Section 1—Getting Acquainted This section provides a general description of the FM250G transmitter and introduces you to safety conventions used within this document. Review this material before installing or operating the transmitter. Getting Acquainted 1—1... -
Page 8: Your Transmitter
Rev A Your Transmitter The FM250G is a member 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. -
Page 9: Applications And Options
RF output power which you can expect. The number portion of each name represents the maximum RF output power. The FM250G, for example, can generate up to 250 watts of RF output power. Suffix letters describe the configuration. The FM250GT, for example, is the standard or transmitter configuration. -
Page 10: Stand-Alone
Careful placement of a Crown transmitter, operating on the same frequency as your primary transmitter, can help you reach full coverage. An external receiver and special antenna are required to use Crown FM transmitters as boosters. -
Page 11: Translator
Metering Illustration 1–3 Crown’s Integrated Translator This option enables RF in and RF out on any of Crown’s FM series of transmitters. In addition, the module supplies a composite output to the RF exciter portion of the transmitter. From here, the signal is brought to full power by the built-in power amplifier for retransmission. -
Page 12: Satellator
Some Crown units function as “nearcast” transmitters. Their low-power output is not designed for broadcasting a signal but for transmitting it to local receivers, sometimes within the same room. Crown transmitters have been used in this way for language translation, for rebroadcasting the audio of sporting events within a stadium, and for specialized local radio. -
Page 13: Transmitter/Exciter Specifications
Rev A Transmitter/Exciter Specifications Frequency Range 87-108 MHz RF Power Output (VSWR 1.5:1 or better) 50-250 watts, adjustable 50 Ω RF Output Impedance 50 kΩ bridging, balanced, or 600 Ω Audio Input Impedance Audio Input Level Selectable for -10 dBm to +10 dBm for 75 kHz deviation at 400 Hz Pre-emphasis Selectable for 25, 50, or 75 µsec;... -
Page 14: Receiver Specifications
2.8 µV for signal-to-noise > 40 dB Stereo Sensitivity (19–kHz pilot frequency added) 8 µV for signal-to-noise > 50 dB 31 µV for signal-to-noise > 60 dB Standard type N, 50 Ω Connector Shipping Weight 1 lb 1—8 FM250G User’s Manual... -
Page 15: Safety Considerations
Rev A Safety Considerations Crown Broadcast assumes the responsibility for providing you a safe product and safety guidelines during its use. “Safety” means protection to all individuals who install, operate, and service the transmitter as well as protection of the transmitter itself. - Page 16 Rev A 1—10 FM250G User’s Manual...
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Page 17: Section 2-Installation
Section 2—Installation This section provides important guidelines for installing your transmitter. Review this information carefully for proper installation. Installation 2—1... -
Page 18: Operating Location
Do not locate the transmitter directly above a hot piece of equipment. Power Connections The FM250G operates on 120 or 240 volts AC (50 or 60 Hz; single phase). As shipped (factory default settings), the FM250G operates on 240 volts at 60 Hz. - Page 19 Rev A 115V Illustration 2–1 Opening the Power Connector Cover 115V Illustration 2–2 Removing the Voltage Selection (red) Assembly 6. Connect the AC power cord. Input Power Fuze Size 120 VAC 10 ampere 240 VAC 4 ampere Table 2-1 Fuse Size Installation 2—3...
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Page 20: Frequency (Channel) Selection
(The selected number will appear directly above the white indicator dot on each switch.) See examples of selected fre- quencies in the illustration below. = 88.1 MHz = 107.9 MHz Illustration 2–5 Example Frequency Selections 2—4 FM250G User’s Manual... -
Page 21: Modulation Compensator
This chip is replaceable. Should you need to change the location of your translator, contact Crown Broadcast for a replacement chip with your new FSK ID. To disable auto ID, remove the jumper from the auto ID location on header HD2 on the RF Exciter Board. -
Page 22: Receiver Frequency Selection
Note: If you requested it, the FSK chip on the RF Exciter Board has been pre-programmed for your operating frequency. This chip is replaceable. Should you need to change the location of your translator, contact Crown Broadcast for a replacement chip with your new FSK ID. Replace the top cover before operating the transmitter. - Page 23 Rev A Frequency Frequency Frequency SW1 Frequency 87.9 92.9 97.9 102.9 88.0 93.0 98.0 103.0 88.1 93.1 98.1 103.1 88.2 93.2 98.2 103.2 88.3 93.3 98.3 103.3 88.4 93.4 98.4 103.4 88.5 93.5 98.5 103.5 88.6 93.6 98.6 103.6 88.7 93.7 98.7 103.7...
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Page 24: Rf Connections
If your transmitter is equipped with the receiver option, connect the incoming RF to the RF IN connector. RF Output RF Input Connector (receiver option only) 120Vac RF Output Monitor Illustration 2–8 RF Connection 2—8 FM250G User’s Manual... -
Page 25: Audio Input Connections
Rev A 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. -
Page 26: Sca Input Connections
You may feed composite stereo (or mono audio) directly to the RF exciter, bypassing the internal audio processor and stereo generator. To use the Crown transmitter as an RF Exciter only (“E” version or when using the “T” version with composite input), it is necessary to use the Composite Input section of the transmitter. -
Page 27: Audio Monitor Connections
Rev A RIGHT LEFT/MONO SCA IN MONITOR COMPOSITE IN REMOTE I/O Composite In BNC Connector Audio Monitor Jacks Illustration 2–11 Composite In and Audio Monitor Connections 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. -
Page 28: Program Input Fault Time-Out
15–pin, D-sub connector on the rear panel. (No connections are required for normal operation. Remote I/O RIGHT LEFT/MONO SCA IN MONITOR COMPOSITE IN REMOTE I/O Illustration 2–12 Remote I/O Connector Table 2-4, Remote I/O Connector, summarizes the Remote I/O pin connections. 2—12 FM250G User’s Manual... -
Page 29: Carrier Frequency
Rev A Pin Number Function Ground (no connection) Composite Out (sample of stereo generator output) FSK In (Normally high; pull low to shift carrier frequency approx- imately 7.5 kHz. Connect to open collector or relay contacts of user-supplied FSK keyer.) /Auto Carrier Off (Pull low to enable automatic turnoff of carrier with program failure.) Meter Battery (unregulated DC voltage;... - Page 30 Rev A 2—14 FM250G User’s Manual...