Becker Electronics CNR Freda and CR Swart Drive Randburg Johannesburg South Africa 2169

Transcription

1 Application & Brief The Becker UHF Bi-Directional Amplifier is typically used in Mining, Shipping, Tunneling, Motorway and In-Building radiating cable systems to compensate for Leaky Feeder Cable longitudinal losses in both directions simultaneously. Becker BDA specifications are optimally suited to maximize these performance criteria. The BDA serves to maintain the strength of RF signal levels along the Leaky Feeder coaxial cable. The amplifier is unique in that it offers the lowest possible noise contribution to an already weak RF carrier when operating in collocation with a strong carrier. The connectors of the inline amplifiers have been designed for ease of connection making installation and repair as convenient as possible. The Power Source required from the Leaky Feeder cable is 5V to 26Vdc. The most important performance criteria of a BDA are: Channel capacity - Number of simultaneous voice and data Channel quality (clear voice channels, data channel, and integrity). Channel isolation (Freedom from inter-modulation distortion). Distance achievable away from the cable. Reliability and Mean Time-Between-Failure channels. Becker BDA specifications are optimally suited to maximise these performance criteria. Functional Features Technical Features DC Power Voltage status indicators on front panel. DC Power Amplifier Current consumption indicators on front panel. Downlink signal strength indicators to ensure line spacing is correct. Uplink AGC ON indication to ensure up-link is working correctly. Integrated Cable Length Compensation (CLC) to simulate additional cable lengths as necessary. Optimized noise performance in VHF Leaky Feeder systems. Carefully distributed amplification using low voltage GaAs devices in both directions to optimize overall figure under dynamic (Small and Large Simultaneously) conditions. Protection: Transorb Diodes that clamp transient energy at defined voltage levels. Protection: Switch-mode Voltage Regulator which reduces the applied voltage on the Leaky Feeder line down to the internally required 3 volts. Protection: A poly-switch to protect the amplifier circuitry in the event of excess current drain. Purchase Contact Details Becker Electronics CNR Freda and CR Swart Drive Randburg Johannesburg South Africa 2169 Tel: Fax: Website: sales@beckerelectronics.co.za DISCLAIMER All information given in this datasheet is correct to the best of our knowledge, but the company reserves the right to make alterations and amendments to the detailed specification at its discretion. Page 1 of 5

2 Interpretation Of Bi-Directional Amplifier Specifications BDA's are inserted into the Leaky Feeder cables (transmission lines) to compensate for the longitudinal losses through the cable. Leaky Feeder gradually radiates a portion of the radio power contained in the cab replenished by the BDA's. As such, their primary electrical specifications are based around the following attributes: SELECTIVITY - Ability to pass wanted frequencies and reject interferers. GAIN RESPONSE RIPPLE - Deviation of Gain from centre of pass band. OPEN LOOP GAIN - Ability to amplify small signals to their original strength. OUTPUT POWER SET POINT - Nominal radio signal strength amplifiers strives to retain at output. NOISE FIGURE - BDA's contribution to overall system noise floor. CHANNEL CAPACITY - Number of simultaneous. Performance Specifications Frequency range Voice/ Data Base to Handheld 470 MHz 480 MHz (Downlink) Handheld to Base 445 MHz 455 MHz (Uplink) Channel Capacity 80 Channels Up 80 Channels Down Down Link Open Loop Gain 22dB min Gain Response Ripple 1.6dB maximum Downlink Nominal Output Set point 0dBm Typical LED LOW Threshold -22dBm Typical LED GOOD Threshold -21dBm Typical LED HIGH Threshold -20dBm Typical LED HIGH HIGH Threshold -19dBm Up Link Open Loop Gain 22dB min Gain Response Ripple 1.6dB maximum Uplink Nominal Output Set point 0dBm Typical AGC LED Threshold -18dBm Operating Voltage 5V to 26Vdc Current 12VDC 250mA max Through current capacity 3.0A max. CLC dB Attenuated Gain (Up & Down) 0.5dB steps Environmental Specifications Operating Temperature Limits Storage Temperature Limits Operating Altitude Operating Humidity Protection Class Impact Resistance Flammability Toxicity Electromagnetic Interference (EMI) -20 o C to +40 o C -40 o C to + 65 o C Up to 5500m ASL 10 to 85% (Non Condensing) IP68 according to EN Nm Body Only Not indicator lights UL94 V-O Halogen and Cadmium Free FCC Emissions Class A (Industrial) CE Emissions Class A (Industrial) Page 2 of 5

3 Typical Response Curve Remote CLC Attenuator Performance Internal Circuitry Page 3 of 5

4 DIP SWITCHES CLC Interface & Control The CLC (Cable Length Compensation) of the Bi-Directional Amplifier allows the installation technician to simulate an additional length of cable on the Base Station (left hand) side of the Amlifier. On an Amplifier s PCB you ll find two dip switches and one rotary switch with sixteen possible settings, enabeling the installation technician to change the CLC settings and make alterations as desired. To explain the cable length compensation a table is layed out below: No compentation is made when the rotary switch is set on zero, the arrow pointing towards the zero symbol, and both the dip switches are switched off. When altering the CLC interface each single adjustment will approximately add an additional 0.5dB compensation to the main line (from the Base Station side of the Amplifier). The AGC takes care of any further errors. Setting db CLC (Cable Length Compensation) Rotary position A B C D E F DIP1 OFF DIP2 OFF DIP1 ON DIP2 OFF DIP1 OFF DIP2 ON DIP1 ON DIP2 ON Page 4 of 5

5 Table showing the cable length compensation (CLC) of the amplifing unit. The rotary switch has 16 positions. Each position represents -0.5dB CLC compensation. For accurate assessment ensure that both the DIP switches are OFF before adjusting. On the rotary switch, point the arrow towards 0, this will result in a 0dB CLC, setting the rotary switch on F will add -7.5dB CLC. Switching ON the +8dB switch increases the rotary switch value by 8dB, giving you an 8 to 15.5dB range. Switching ON the +16dB switch increases the rotary switch value by 16dB, giving you a 16 to 22.5dB range. Switching ON both the +8dB and the +16dB switch increases the rotary switch value by 24dB, giving you a 24 to 31.5dB CLC range. Mechanical Specifications Width (Excluding mounting brackets) Height (Excluding mounting brackets) Depth (Excluding mounting brackets) Weight Principal Materials Finish Gasket Mounting Options 230mm 75mm 61mm 1.24kg Enclosure: Glass Reinforced Polyester GRP Connectors: Electroplated Brass Thermoplastic polymer glass fiber Black Silicon rubber 4 holes M6 directly Mechanical Drawing Ordering Information NON-IA Part No: UBDA220AU# XXXXXX (Base Part No.) (Serial No) What s In The Box UHF Bi-Directional AMP Datasheet Test Results Sheet Page 5 of 5