Richardson Electronics MT300 300W FM Transmitter User Manual 430026

Richardson Electronics Ltd 300W FM Transmitter 430026

Exhibit D Users Manual per 2 1033 c3

RFCAST – MT300. Rev. 2: 05-17-04 1/17 OWNERS MANUAL Model MT300 (-E & -U) 300 WATT FM STEREO TRANSMITTER
RFCAST – MT300. Rev. 2: 05-17-04 2/17 Table of Contents Table of Contents page 2 User Notices page 4 Warning page 5 Returns & Exchanges page 6 Unpacking page 6 Technical Support page 6 1.0 Overview page 7 2.0 MT300 Basic Block Diagram page 7 3.0 Subassemblies Description Page 7 3.1 MT300 AC/DC Power Supply page 7 3.2 MT300 DC/DC Power Supply page 8 3.3 FM Stereo Exciter page 8 3.4 MT300 RF Control Circuit page 8 3.5 MT300 RF Amplifier page 9 3.6 Low Pass Filter and Directional Coupler page 10 4.0 MT300 Technical Specifications page 10 5.0 Set up Procedure page 12
RFCAST – MT300. Rev. 2: 05-17-04 3/17 OME-1T Exciter Section 6.0 General / Front Panel Graphic Page 1 of 4 7.0 Physical Page 2 of 4 8.0 Monaural Operation Page 2 of 4 9.0 Wideband Stereo Operation Page 2 of 4 10.0 Built In Stereo Encoder Operation Page 3 of 4 11.0 SCA/RDS & AUX Inputs Page 3 of 4 12.0 OME-1T Component Layout Page 4 of 4 13.0 Jumper and Switch Setting guide Page 4 of 4 Schematic Diagrams and Components Locations 14.0 OME-1T Schematic Diagram 15.0 300W RF Module 16.0 Layout FM300-108SD 17.0 MOSFET FM 300W RF Amplifier Schematic 18.0 Layout MDL30 19.0 MDL30 Schematic 20.0 MT300 / MT250 Logic Control Board Layout 21.0 Logic Control Board MT250 / MT300 Schematic 22.0 300W Low Pass Filter Layout – MT100/250/300 Low Pass Filter 23.0 300W Low Pass Filter Schematic 24.0 300W Directional Coupler Layout 25.0 300W Directional Coupler Schematic 26.0 DC/DC Converter Layout 27.0 DC/DC 90W Converter Schmatic 28.0 JWS300 – 600 Series Instruction Manual
RFCAST – MT300. Rev. 2: 05-17-04 4/17 USER NOTICES IT IS VERY IMPORTANT TO READ THE FOLLOWING MANUAL SECTIONS PRIOR TO OPERATION OF THIS TRANSMITTER! Notice 1 The transmitter main operating voltage setting is marked on the rear of the MT300 chassis. It may be necessary to change this setting for your operating condition. Please refer to AC Main Voltage Setting in section 6.0 Set Up Procedure. Notice 2 The transmitter operating frequency from the factory may not be set for your authorized frequency as it is normally set for a mid band value such as 98.0 MHz. Please refer to Frequency Of Operation Change in section 6.0 Set Up Procedure. Notice 3 For adjusting the RF output power setting a qualified technician should employ the use of an RF Wattmeter and a calibrated dummy load. Please refer to the section entitled RF Power Control in section 3.4 of this manual. Notice 4 The factory settings of this manual for such this as Input Selection, preemphasis, and input sensitivity may not be correct for your application or installation requirements. Please refer to the other exciter settings in section 6.0 Set Up Procedure where you will be directed where else to reference in this manual. GENERAL COMMENTS THIS PRODUCT DOES NOT INCLUDE A DETAILED TECHNICAL MANUAL, RATHER AN ENHANCED OPERATORS MANUAL. WHAT THIS DOCUMENTATION IS INTENDED TO DO IS TO GIVE THE USER THE CORRECT INSTRUCTIONS AND INDICATIONS ABOUT HOW TO OPERATE AND PERFORM PERIODIC CHECKS AND DETERMINE IF THE TRANSMITTER IS FUNCTIONING PROPERLY. WE ARE AWARE THAT THE TRANSMITTER DOCUMENTATION MAY PRESENT SOME SMALL AMBIGUITIES AND IMPERFECTIONS, MANY OF WHICH HAVE ALREADY BEEN NOTED AND RESOLVED IN THE NEXT RELEASE AND PRODUCTION. FOR THIS REASON, EVERY OBSERVATIONS/SUGGESTIONS OR PARTICULAR COMMENTS ARE WELCOME. ELECTRONIC FILES OF THE SCHEMATIC DIAGRAMS IN THIS MANUAL ARE AVAILABLE. SHOULD A LARGER MORE VIEWABLE VERSION OF ANY DIAGRAM BE REQUIRED NOTIFY RICHARDSON ELECTRONICS, LTD. TO CALL OUR TECHNICAL SUPPORT CENTER OR FOR OTHER CUSTOMER SERVICE ISSUES AT RICHARDSON ELECTRONICS IN LA FOX, ILLINOIS REFER TO THE FOLLOWING NUMBERS: TECHNICAL SUPPORT: 630-208-2790 CUSTOMER SERVICE: 630-208-2304
RFCAST – MT300. Rev. 2: 05-17-04 5/17 WARNING! THE VOLTAGES AND CURRENTS IN THIS EQUIPMENT ARE DANGEROUS. PERSONEL MUST, AT ALL TIMES, OBSERVE SAFETY WARNINGS, INSTRUCTIONS, AND ANY REGULATIONS. This owner’s manual is intended as a general guide for trained and qualified personnel who are aware of the dangers that are inherent in the handling and operation of potentially hazardous electrical and electronic circuits. It is not the intent of this manual to provide a complete set of safety instructions or precautions that should already be understood by trained or experienced personnel in using this or other types of electronic equipment. The installation, operation, and maintenance of this equipment involves risks to personnel and also to the equipment. Broadcast Richardson or Richardson Electronics, Ltd. shall not be responsible for injury or damage that is the result of improper procedures or use by persons improperly trained or lacking the knowledge to perform associated tasks. All local codes for building, safety, fire, or related standards must be observed. Consult local authorities for the standards for the area or region where the equipment will be installed and put in use. WARNING! AT ALL TIMES DISCONECT AC/MAINS POWER BEFORE OPENING COVERS, DOORS, ENCLOSURES, PANELS, OR PROTECTIVE SHIELDS THAT EXPOSE LIVE CIRCUITS. USE ANY GROUNDING STICKS OR OTHER SHORTING PROBES TO DRAIN ENERGY FROM CIRCUITS BEFORE SERVICING. NEVER PERFORM MAINTENANCE, MAKE ADJUSTMENTS, OR SERVICE THE EQUIPMENT WHEN ALONE OR FATIGUED. WARNING! IF ELECTROLYTIC OR OIL FILLED CAPACITORS ARE UTILIZED IN THE EQUIPMENT AND THE COMPONENT APPEARS LEAKY, OR IS BULGING, OR IF THE CASE OR COVERING OF THE COMPONENT APPEARS DAMAGED OR DISTRESSED ALLOW SUFFICIENT TIME FOR THE UNIT TO COOL OR FULLY DISCHARGE BEFORE SERVICING. SERVICING HOT OR LEAKY CAPACITORS CAN CAUSE A RUPTURE OF THE CASE AND POSSIBLE INJURY. Should accident or injury occur personnel engaged in the installation, operation, or service of the equipment should seek proper medical attention. It is advisable that such personnel have familiarity with first-aid practices.
RFCAST – MT300. Rev. 2: 05-17-04 6/17 Returns and Exchanges Equipment (Damaged or undamaged) should not be returned unless written approval and a Merchandise Return Authorization (MRA Number) is received from your Richardson Sales representative or Richardson Customer Service. Special shipping instruction will be provided which will assure proper handling. The circumstances and reasons for the return must be included in the request for return. Equipment that is special or “custom” ordered may be not returnable. In situations where return or exchange is at the request of the customer a restocking fee may be charged. All returns must be sent freight prepaid and properly insured by customer. When communicating with Broadcast Richardson please refer to your Order or Invoice Number. Unpacking Use care when unpacking the equipment. First perform a visual inspection of the item(s) to determine if any damage occurred during shipment. Be sure to retain all the shipping materials (crates and boxes or cartons) until such time that it has been determined that the received equipment arrived undamaged. Find all PACKING LISTS and keep them to assist in locating and identifying any components or assemblies that may have been removed for shipping and might need to be reinstalled in the equipment. Make sure that all shipping straps, supports and packing materials are completely removed from the equipment prior to initialization and use. Technical Support Should you need technical assistance or trouble shooting guidance contact Broadcast Richardson in your local area or you can reach assistance from Broadcast Richardson in La Fox, Illinois at telephone +1 (630) 208-2782, Fax +1 (630) 208-2551 or Customer Service at +1 630-208-2304. Throughout the world there are many Richardson Electronics, Ltd. offices that are also able to assist in contacting our technical support team.
RFCAST – MT300. Rev. 2: 05-17-04 7/17 MT300 FM LOW POWER TRANSMITTER 300 WATT 1.0 OVERVIEW MT300 is a 300 Watt FM Stereo Low Power Transmitter. It is very simple and easy to operate. It is composed of a mechanical frame (19 inches std., 3 RU high and 500mm depth), a stereo exciter (OME-1T), a RF section, comprised of a RF control board and an amplifier section, a directional coupler and low pass filter, a display, and power supply composed of a AC/DC converter and a DC/DC converter. 2.0 BASIC BLOCK DIAGRAM OF MT300 FANSFUSE48 Vdc-V+V LED (DISPLAY)ENABLE110/220VL.P.F.Delay lineRF outLOW PASS FILTER andDIRECTIONAL COUPLERRF AMPLIFIER SECTIONREFL1 REFL2 FWD RF PROTECTIONDRIVER(MDL30)FINAL STAGE (FM300-108)TEMPERATURERF CONTROL CIRCUIT RF MonitorAC/DC CONVERTERDC/DC CONVERTER48 Vin28 Vdc15 VdcFANsEXTERNAL ENABLEOME-1T FM ExciterRFout 1WmaxLeftRigthExt/MPXSCA/RDSAUX 15Vdc 3.0 SUBASSEMBLIES DESCRIPTION 3.1 MT300 AC/DC Power Supply This power supply is a vendor-supplied product. The supply is an AC/DC supply that has a wide operating range permitting input voltages of 85 to 265 V producing an output voltage of 48V. Below are the technical specifications:
RFCAST – MT300. Rev. 2: 05-17-04 8/17 Nominal Output Voltage 48V Max Output Current 13A Max Output Power 624 Watt Efficiency 83% typ. Input Voltage Range 85-265VAC (47-63Hz) PFHC Built to meet EN61000-3-2 Power Factor(100/200VAC) (typ) 0.99/0.95 Output Voltage Range 43.2-52.8V Over Voltage Protection 55.2-64.8 3.2 MT300 DC/DC Power Supply The MT300 uses a DC/DC converter to provide a voltage of 15V to the exciter and a pulsed voltage of 28V to the fans (pulsing does not reduce the fans effectiveness but provides for hard start conditions). In addition, it supplies a voltage of 28V to the driver (MDL30). Below, are the technical specifications: Vdc Input 20 up to 53 Vdc Output 1 15 Vdc/1.5 A Output 2 28 Vdc/3 A 3.3 FM Stereo Exciter The exciter is RFCast model OME-1T. The declared nominal RF output power is 1 Watt; this signal is delivered to the RF final stage through the RF protection circuit. All the input connections are arranged on the front panel. (See the annex datasheet at a later section in this manual). Located on the rear panel of the MT300 are also Left & right audio inputs that appear on a screw terminal strip for convenience when rack mounted. 3.4 MT300 RF Control Circuit The RF input circuit has 3 main functions: RF power control RF protection
RFCAST – MT300. Rev. 2: 05-17-04 9/17 Measurement/status indication RF Power Control. A pin diode attenuator controls the RF input power coming from the exciter (OME-1T). This attenuator can be manually controlled by trimmer RT3 located on the internal control panel, to permit adjustment for the desired output power. To access RT3 the operator engineer will need to remove the transmitter top cover and locate the trimmer on the control panel using the Logic Control Board Layout Drawing found later in this manual. An AGC control regulates the output power, manually set, versus frequency and/or temperature changes. Moreover, the input attenuator includes a soft start, activated when switching on or after any RF protection intervention. When the MT300 operates at a very high temperature and/or high reflected output power, a derating circuit is provided to decrease the output power to maintain equipment operation, although at a lower power. RF Protection. A fast comparator switches when the detected output reflected power exceeds a pre-set threshold. The regulation of this threshold is made by RT2 trimmer, factory adjusted to a value of 30 Watts reflected power. When the protection is activated, the protection circuitry removes the RF drive signal applied to the final stage amplifier very quickly, in about 1 micro second. Measurement/status indication. The two main measurements, FWD and REF power, are displayed by two BAR LEDs. The MT300 status is indicated with 3 LEDs: RF nominal, RF fault, RF derating. The RF fault is turned on when the output power is lower than 3 dB related to the nominal output power. If the power decreases in derating conditions, the fault is off in all cases. The enable switch SW1 is on the front panel. It is possible to turn on (enable) the transmitter using the contacts on the screw terminal on the transmitter rear panel. Enable or turning on the RF amplifier is realized when switch SW1 is in the on position and the rear panel enable is closed using a jumper connection or external relay. WARNING: with enable off, there is no RF output, however all internal circuits are powered (stand by condition). For safety, it is important to switch off the mains voltage source or unplug the transmitter before operating inside. Be sure to return the transmitter cover before operating to permit the proper airflow and cooling of components.
RFCAST – MT300. Rev. 2: 05-17-04 10/17 3.5 MT300 RF Amplifier The RF amplifier section serves to amplify the RF signal coming from the RF control circuit and exciter. It is composed of: MDL30 (Driver) FM300-108 (Final Stage) The MDL30 provides the first step of amplification of minimum 17dB gain in order to correctly drive the final stages. It is composed of a stage operating in class AB. Below, the technical specifications: VCC 28V Idq 200 mA typ. Frequency range FM ( 87.5-108 MHz ) Power Gain > 17 dB typ. Output Power > 25 W The final stage is an RF amplifier for FM signals operating in band II (87.5 – 108 MHz), with nominal output power of 300 Watt CW. Normally it works up to 330 Watt, in order to overcome the Insertion loss of the circuitry that follows the amplifiers, being the Directional couplers and Low Pass Filter. FM300-108 uses MOSFET technology where the RF MOSFET‘s bias is integrated on its printed circuit board. The polarization is in class B, with a 180 mA quiescent current. VCC nominal 48V IDC (@ Full Power) 11 A typ. Idq 180 mA typ. Frequency range FM ( 87.5-108 MHz ) Power Gain Typ. 18 dB Output Power 300 W min
RFCAST – MT300. Rev. 2: 05-17-04 11/17 3.6 Low Pass Filter and Directional Coupler Unit The filter has a particular elliptic configuration; this configuration has been specifically chosen to guarantee the values of the harmonic components levels. In-band Insertion Loss <0.5 dB Insertion Loss @ 175MHz >55 dB In-band Return Loss <-20 dB The directional coupler is a block composed by 2 directional couplers and a quarter wave delay line. Both ports of each directional coupler are used. Two of them detect the reflected power, one detects the FWD power and one is used as RF monitor. The function of the delay line is to have two reflected power signals detected at 90° of electrical angle. In this way, it is possible to have a quite constant reflected power level vs. the phase angle of that signal. The RF monitor is connected to the front panel (RF monitor port) to have 0 dBm nominal signal. 4.0 MT300 Technical Specifications Environmental Storage Temperature: -20/+65 °C Operating Temperature: -5/+45 °C Guarantee Performance Temperature: 0/+45 °C Relative Humidity (Non Condensing): < 90% Guarantee Performance Altitude: 2000 m, (6560 ft) Cooling: > 150 cubic meters/hour
RFCAST – MT300. Rev. 2: 05-17-04 12/17 RF Characteristics Frequency Range: 87.5 – 108 MHz, 50Khz step, synthesized. Output Power: 300 Watts nominal, (VSWR < 1.8:1). RF Power Devices Technology: MOSFET Off lock Attenuation: > 60 dBc RF Output connector: N Female RF Output Impedance: 50 Ω RF Output monitor level: 0 dBm nominal (BNC connector on the front panel) RF Spurious: < -95dBc @ +/-1MHz (Exceed .EBU/CCIR/FCC) Harmonic: < -70dBc Frequency stability: < 500 Hz / 6 months @ Center Frequency Inputs: Mono, Stereo, MPX, AUX, SCA/RDS Input Impedance: 600Ω or 5KΩ unbalanced Modulation Type: F3E/F8E Direct FM at the carrier frequency Frequency deviation: +/-75KHz=100% Variation of sensitivity for 75 KHz Deviation: +/-1dB from 87.5 to 108 MHz AF Limiter: +1dB Center Frequency Shift: < +/-500Hz, (Due to +/-75KHz Mod) Stereo Operation: CCIR 450/S2 “Pilot Tone System” Asynchronous AM SNR: (REF=100% AM Mod, @400Hz, BW=30Hz to 20KHz, FM Mod OFF) - 56dB Synchronous AM SNR: (REF=100% AM Mod, @400Hz, BW=30Hz to 20KHz, FM Mod +/-75KHz @400Hz) -50dB
RFCAST – MT300. Rev. 2: 05-17-04 13/17 Electrical Power Supply: 96/130 or 200/268 V, Single Phase AC, 48 to 62Hz. Power Consumption: < 620 VA Power Factor: > 0.9 R & Mono Input Input connectors: BNC female (front panel) Input Impedance: 1 Mohm resistive, unbalanced, source impedance <10kOhm Input level (For +/-75KHz deviation): 3 to 9 dBm/600Ω Frequency response (30Hz to 15KHz): +/- 0.15dB Pre-emphasis: Flat/50µSec/75µSec +/-3% THD (30Hz to 15KHZ): 0.1% FM S/N Ratio (REF=+/-75KHz): Weighted CCIR 468-2; BW= 30Hz to 20KHz flat -68dBc with de-emphasis 50µsec -73dBc with de-emphasis 75µsec -76dBc No-weighted; BW= 30Hz to 20KHz flat -73dBc with de-emphasis 50µsec -76dBc with de-emphasis 75µsec - 78dBc Audio Filter rejection: (19KHz to 100KHz) >30 dB 19KHz suppression: > 46dB
RFCAST – MT300. Rev. 2: 05-17-04 14/17 External MPX Input Input connectors: BNC female (front panel) Input Impedance: 10KΩ Input level (For +/-75KHz deviation): 3 to 9 dBm/600Ω Composite amplitude response (30Hz to 100KHz): +/- 0.5dB Composite phase response ( 30Hz to 53KHz): +/- 0.5° SNR: (30Hz to 200KHz; with de-emphasis 50µsec) > 75dB Stereo Operation (L & R Channels) Input connectors: BNC female (front panel) Input Impedance: 1 Mohm resistive, unbalanced, source impedance <10kOhm Input level: 3 to 9 dBm/600Ω Audio Filter Attenuation: > 68 dB @ 19 KHz Crosstalk Attenuation (From 30 Hz to 15 KHz): > 50 dB Pre-emphasis: Flat/50µSec/75µSec +/-3% 38 KHz Suppression: > 50 dB Sub-Carrier Frequency: 38 KHz +/- 2Hz Pilot Frequency: 19 KHz +/- 1Hz Phase Difference 19/38 KHz: 0° +/- 2° THD on Encoded Channels (30Hz to 15KHz): < 0.1% Audio Response (30Hz to 15KHz): +/- 0.25dB Nominal Pilot Deviation: +/- 7KHz Pilot Output level: 1 Vpp, square wave
RFCAST – MT300. Rev. 2: 05-17-04 15/17 SCA/RDS & AUX input Input connectors: BNC type female (front panel) Input Impedance: 5KΩ Input level (for +/-7.5KHz deviation @97.5MHz): 2.2Vpp/5KΩ Amplitude Response (10KHz to 100KHz): +/- 0.15dB
RFCAST – MT300. Rev. 2: 05-17-04 16/17 5.0 Set up procedure The MT300 is shipped in a wooden box. It should be removed carefully removing the foam packing material and the clear protective film. This equipment can be operated freestanding or by its standard mechanical frame (19 inches), it may be mounted in an equipment rack. AC Main Voltage Setting The MT300 is supplied for 220Vac, +/- 15%, single phase at 50Hz or 60Hz operation but it can operate at 110VAC single phase, because its AC/DC power supply capable of a wide operating range. The normal current draw is approximately 2.8 amps for 220Vac operation, but, if supplied at 110Vac, the normal current is around 5.3 amps. It is installer’s responsibility to correctly connect the three wires (line, N, GND) to the mains line use the power cord supplied. It is also recommended that a transient or surge protector be properly grounded and the MT100 connected through the protector. Before switching the transmitter on, it is necessary to connect the RF output power type “N” (female) connector to either a dummy load or an FM antenna with low loss coaxial transmission line. Frequency of Operation Change The MT300 transmitter operating frequency at time of shipment from the factory may not be set for your authorized frequency. In order to change the frequency of operation, locate, the OME-1T exciter section of this manual and review the information on page 4 of 4. After review the frequency setting examples in this section, substitute your values for the switch settings through the OME-1T chassis top. You should make sure that the transmitter is unplugged and that no power present. To access the frequency change selector switches may be necessary to remove the four (4) screws on the front of the OME-1T and slide it forward far enough to allow a small screwdriver blade to adjust the three (3) rotary frequency selector switches.
RFCAST – MT300. Rev. 2: 05-17-04 17/17 Output Power Setting Please refer to the earlier section entitled RF Power Control in section 3.4 of this manual. Other Exciter Settings Please refer to the OME-1T exciter section of this manual, page 4 of 4, for jumper settings for left and right channel preemphasis selection (75 microseconds un-preemphasized, or 50 microseconds), left and right input sensitivity selection (6..9dBm, 3..6dBm or 0..3dBm), modulation limiter selection (On or Off), and input selection (Mono, Multiplex Internal, or Multiplex External). This page of the manual shows the various positions for the jumpers and their location on the OME-1T printed circuit board. Turning On the transmitter After the above procedures are followed, it is possible to turn the transmitter on. On the front panel, the mains power LED indicates the status of the MT300. If it is on, the equipment has been correctly supplied the AC line voltage. By activating the enable switch, on the front panel, the transmitter reaches the maximum RF power set. Other LEDs provide further information on the functioning of the MT300: RF nominal (green): ON if some RF output power appears Derating (yellow): ON in two situations when the reflected power is higher than 10dB (the transmitter power output is maintained until VSWR 2:1. If the VSWR is higher, the derating protection intervenes which stabilizes the output power at a non-dangerous value of operation for the amplifier) when the working temperature is too high (the temperature protection intervenes when the ambient room temperature is ≥45°. In this case, the output power is reduced of about 6dB) Fault (red): ON if the transmitter has other faults (for example, input power without output power, with for example a fault in the RF amplifier or RF control circuit).

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