GPA-9 manual GE MDS GPA-9 Manual P/N draft Rev D. GPA-9 manual Table of Contents 1 Important Information ............................................................................................................ 3 1.1 RF Exposure ................................................................................................................... 3 1.2 FCC Approval Notice ...................................................................................................... 3 1.3 FCC Part 90 Information ................................................................................................. 3 1.4 Product Description ........................................................................................................ 4 1.5 Power Control Loop ........................................................................................................ 4 Interfaces ..................................................................................................................................... 5 1.6 J102 Terminal Block ....................................................................................................... 5 1.7 J100 RF Output .............................................................................................................. 5 1.8 J101 RF Input ................................................................................................................. 5 1.9 R138 Power Control Adjustment .................................................................................... 5 1.10 LED Indicators ................................................................................................................ 5 Installation ............................................................................................................................. 6 2.1 Mounting the Unit ........................................................................................................... 6 2.2 Connecting the Unit ........................................................................................................ 6 3.3 Alignment (Setting power output) ...................................................................................... 6 3.4 Overtemperature Fault ....................................................................................................... 6 3.5 VSWR Fault ....................................................................................................................... 6 GPA-9B smaller heat-sink option ................................................................................................ 7 GPA-9 standard heat-sink option ................................................................................................ 7 Unit Specifications ....................................................................................................................... 8 3 Technical Assistance ............................................................................................................ 8 4 Change Log ........................................................................................................................... 8 2 GPA-9 manual 1 Important Information 1.1 RF Exposure Professional installation required. The radio equipment described in this guide emits radio frequency energy. Although the power level is low, the concentrated energy from a directional antenna may pose a health hazard. Do not allow people to come closer than 1.12 meters, (3.7 feet) to the antenna when the transmitter is operating with a unity gain antenna. This is an RF amplifier, the maximum ERP for this FCC band is 500 watts, this equates to an RF safety distance of 3.82 meters. Please consult the FCC website below for RF safety distances, using different antenna gain configurations which affect the ERP. More information on RF exposure can be found on the Internet at:
www.fcc.gov/oet/info/documents/bulletins. 1.2 FCC Approval Notice This device is offered as a licensed Amplifier per FCC Part, 90. It is approved for use under the following conditions: Changes or modifications not expressly approved by GE MDS will void the users authority to operate the equipment. 1.3 FCC Part 90 Information For FCC Part 90, valid frequencies are 896-940 MHz at up to 500 Watts ERP Caution; Only use authorized antennas that meet the FCC license requirements. Use of unauthorized antennas, cables, and/or coupling devices not conforming with ERP/EIRP for outdoor/indoor will void the licensees license to operate. WARNING: This is NOT a CONSUMER device. It is designed for installation by an installer approved by an ISED licensee. You MUST have an ISED LICENCE or the express consent of an ISED licensee to operate this device. AVERTISSEMENT: ce n'est PAS un appareil CONSOMMATEUR. Il est conu pour tre install par un installateur approuv par un titulaire de licence ISED. Vous devez avoir une LICENCE ISED ou le consentement exprs d'un titulaire de licence ISED pour utiliser cet appareil. GPA-9 manual Introduction The GPA-9 is an RF power amplifier designed for use in the 896-940MHz frequency range at up to 40 Watts. The A version is intended to serve as a 100% duty cycle amplifier for MDS SD9 and other MDS radios operating in point-to-multipoint repeater or base applications. 1.4 Product Description The GPA-9 power amplifier consists of an RF amplifier and PCB mounted to a heat sink, with a DC Power interface, PTT and input/output RF connections on the sidewalls of the chassis. DC power is supplied to the amplifier from a regulated and filtered DC source capable of supplying 10-16 Vdc at a maximum current of 10 Amperes. The DC power source should be current limited or have a protective fuse or circuit breaker. 1.5 Power Control Loop The GPA-9 amplifier uses a feedback circuit within the amplifier to control the output power. The set point is set by potentiometer R138, accessed near the RF input connector. Further, the PA performs TX/RX switching to provide a low loss receive path when not transmitting. The TX/RX control is performed by RF detection within the PA. There is also a PTT (Push to Transmit) input on the terminal strip. RF IN J101 RF OUT J100 Power Control R138 TX RX Figure 1 R138 Location GPA-9 manual Interfaces The J102 terminal block provides keying and power control signals. 1.6 J102 Terminal Block Table 1 J102 Control Cable Pin Functions Pin Pin 1 Pin 2 Pin 3 Pin 4 Function 13.8V nominal 10 amps DC input Power supply Ground ground PTT (ground to transmit) 1.7 J100 RF Output J100 is a 50 Ohm Female Type N connector. J101 is a 50 Ohm Female Type N connector. 1.8 J101 RF Input 1.9 R138 Power Control Adjustment R138 is used to adjust the RF power output of the amplifier in internal and mode. Turn the potentiometer clockwise for higher power and counterclockwise for lower power. RF output power will depend on power supply voltage (10-16V DC) and RF drive level (+27 to +30dBm) 1.10 LED Indicators A pair of LED indicators are located next to the Power Adjustment. The lower indicator (GREEN) will indicate that DC power is applied and the PA is in the receive state. The upper indicator (RED) will indicate that the PA is in the transmit state. If both are on it indicates an Overtemperature fault. (See section 3.4) GPA-9 manual 2 Installation 2.1 Mounting the Unit The GPA-9 A version is designed for mounting in a standard 19inch rack cabinet using the 3U panel provided. Four screws (not provided) are required to attach the panel to the rack sides. This panel also serves as a heat sink for the PA module, and is normally mounted with the cooling fins facing outward. The GPA-9 B version uses a smaller heatsink (intermittent duty) but has the same 4 mounting screws. 2.2 Connecting the Unit Place the amplifier module in service by making the following cable connections. 1. Using low loss 50-ohm coaxial cable, connect the RF Input connector (J101) to the RF output 2. Using low loss 50-ohm coaxial cable, connect the RF Output connector (J100) to the station 3. Connect 10-16 Vdc power supply (13.8V nominal) to the Power connector (J102). The outside pin connector of the MDS SD9 radio. duplexer or antenna. is positive (+); the next is negative (). 3.3 Alignment (Setting power output) Adjusting RF Power Output To check/set the amplifiers RF power output, proceed as follows. 1. Connect a wattmeter (rated for use at 900 MHz, and at least 40 watts) to the amplifiers RF output connector (J102). 2. Terminate the wattmeter into a 50-ohm, non-inductive load. 3. Set SD9 PWR=30dBm. (+27 to +30dBm is allowed) 4. Apply RF drive from 900 MHz radio and note the RF power indication at J100. 5. If necessary, adjust R138 (see Figure 2) with an insulated flat blade tool to achieve the desired output level. Access to this control is available near the RF input connector 3.4 Overtemperature Fault If the flange temperature of the active device in the PA exceeds recommended limits (90C) the PA bias will be automatically removed reducing output power. At this time the GREEN LED will be ON at the same time as the RED LED when the unit is in transmit. When temperature falls within limits normal operation will return. 3.5 VSWR Fault GPA-9 will automatically reduce output power if a high VSWR is detected. GPA-9 manual GPA-9B smaller heat-sink option GPA-9 standard heat-sink option GPA-9 manual Unit Specifications Specification 10-16 Vdc. 13.8V nominal 10 Amperes @ 13.8V, 40W RF Out. SD9 PWR=30dBm
+40 to +46 dBm (10-40 watts), adjustable 100% up to full output power 30% above 10 Watts 896-940 MHz standard 19-inch rack cabinet 5.15 lbs. 5.25 H x 19 W x 2.88 D (13.34 H x 48.26 W x 7.31 D cm) 5.25 H x 7 W x 2.88 D (13.34 H x 17.78 W x 7.31 D cm) E5MDS-GPA-9 GE MDS LLC Table 2 Unit Specifications Parameter Operating Voltage Maximum Current Draw RF Drive Power RF Out Duty Cycle (GPA-9A model) Duty Cycle (GPA-9B model) Operating Frequency Mounting Approximate Weight Dimensions (GPA-9A model) Dimensions (GPA-9B model) FCC Identifier Name of Grantee 3 Technical Assistance For assistance, contact us using one of the following methods:
Telephone: 585.241.5510 E-mail: gemds.techsupport@ge.com Web: www.gemds.com 4 Change Log Version A B C Author D.McCarthy T Hodge T Mayo Date 5/5/17 5/15/17 Changes Initial release Corrections for FCC filing Corrected nomenclature for GPA-9A and GPA-9B