Crown Low Power Transmitters - Crown Broadcast

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5.19.1 Main Channel Into Sub Feed the left and right channels in phase with audio (L+R) at 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz at 100% modulation, while observing the stereo subcarrier (L-R) level on an FM modulation monitor. 5.19.2 Sub Channel Into Main Feed the audio into the left and right channel as above, with the exception of reversing the polarity of the audio of one channel (L-R input). Using the frequencies of 5.19.1 above, observe the main channel (L+R) level with a modulation monitor. 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. Check the functionality of switches and processing control. 3. Verify that all indicators function. 4. Check the frequency synthesizer lock at 80 MHz and 110 MHz. 5. Measure the AC line current with and without the carrier on. 6. Perform a functional test of the SCA input, Monitor outputs, and the monitor and control function at the 15–pin, D-sub connector. 7. Test the functionality of the FSK circuit. 8. Check the operation and timing of the automatic carrier-off circuitry associated with program failure. 9. Check all metering functions. 10. Test ALC action with PA current overload, SWR, and PLL lock. NOTE: FCC type acceptance procedures call for testing the carrier frequency over the temperature range of 0–50 degrees centigrade, and at line voltages from 85% to 115% of rating. (See FCC Part 2.1055.) 5–10 FM30/FM100/FM250 User's Manual
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. Reference Drawings 6–1
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® FM30/FM100/FM250 Broadcast Trans
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Contents Section 1—Getting Acquai
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Section 5—Adjustments and Tests .
Page 7 and 8:
I INFORMATION Section 1—Getting A
Page 9 and 10:
1.2 Applications and Options Crown
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1.2.5 Translator A receiver configu
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1.3 Transmitter/Exciter Specificati
Page 15 and 16: Note: We set voltage and ampere req
Page 17 and 18: ® Section 2—Installation This se
Page 19 and 20: 120Vac Illustration 2-1 Removing th
Page 21 and 22: 2.2.3 Battery Power Your transmitte
Page 23 and 24: 2.3.1 Modulation Compensator The Mo
Page 25 and 26: Frequency SW1 SW2 87.9 0 0 88.0 8 0
Page 27 and 28: 2.6 Audio Input Connections Attach
Page 29 and 30: SCA IN COMPOSITE IN MONITOR RIGHT L
Page 31 and 32: Pin Number Function 1 Ground 2 (no
Page 33 and 34: Section 3—Operation This section
Page 35 and 36: 3. Verify the following: a. The bot
Page 37 and 38: 3.3 Front Panel Bar-Dot Displays Ba
Page 39 and 40: 3.7 RF Output Control Set this cont
Page 41 and 42: in questo mondo, erono due forse, u
Page 43 and 44: 4.2 Audio Processor Circuit Board T
Page 45 and 46: Stereo Generator Board ® FM250 Ill
Page 47 and 48: Principles of Operation 4-7
Page 49 and 50: To get a direct reading of SWR, the
Page 51 and 52: 4.8 Voltage Regulator Circuit Board
Page 53 and 54: 4.11 RF Driver (FM100/FM250) The RF
Page 55 and 56: 4.15 Receiver Circuit Board Option
Page 57 and 58: Section 5—Adjustments and Tests T
Page 59 and 60: Using a Modulation Monitor 1. Set t
Page 61 and 62: 5.3.4 FSK Balance Control An FSK si
Page 63 and 64: 5.8 Bias Set (RF Power Amplifier) T
Page 65: 5.14 Audio Frequency Response For t
Page 70 and 71: 6.2 Board Layouts and Schematics Il
Page 72 and 73: Illustration 6-6 Stereo Generator B
Page 74 and 75: SEE NOTE 10 TOP SIDE COMPONENT MAP,
Page 76 and 77: D 8169-1 Illustration 6-8 RF Meteri
Page 79 and 80: 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
Page 81 and 82: R27 D 8167-5 Illustration 6-10 Disp
Page 84: 2 4 6 8 3 2 1 1 3 5 7 9 6 5 4 3 2 1
Page 87 and 88: R20 R19 Illustration 6-13 Power Amp
Page 89 and 90: Illustration 6-14 RF Output Filter
Page 92 and 93: F 1 2 3 4 5 6 7 8 ADDED TO PWB (200
Page 96 and 97: Section 7—Service and Support We
Page 98 and 99: Crown Broadcast Three Year Limited
Page 100 and 101: Factory Service Instructions To obt
Page 102 and 103: Transmitter efficiency output RF Po
Page 104 and 105: A B C AF ALC AM bandwidth BCD BFO B
Page 106 and 107: A B C pre-emphasis processing recei
Page 108 and 109: Symbols 19-kHz level adjustment 5-4
Page 110 and 111: L labels 1-10 LEDs 3-5, 4-10 line v
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Crown Low Power Transmitters - Crown Broadcast

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