434B Series

Image of 343 Series Mini Autoquad Tower

434B Mission Critical Series, Auto Quad Tower-Top Amplifier (TTA) System is a high performance, quadrature-coupled low noise amplifier (LNA). The TTA increases receive sensitivity, reduces transmit signal interference and can make all the difference in Mission Critical Communications.

The TTA operates independently, monitoring LNA current and automatically switching to a redundant LNA if needed. Status reporting is accomplished via AISG compliant telemetry between the controlling processor in the Tower Box and the base control unit. The base control unit has an on board AISG modem device which does not require the use of an external data cable. This telemetry does not interfere with RF Signals in any way and communicates the LNA currents, temperature and operational status to the base control unit LCD display. Test modes and manual switching between LNA's is also accomplished by way of the telemetry system.

The TTA consists of two components: the tower top amplifier mounted close to the antenna and the control unit. The control unit is available in two styles, either with or without a receiver multicoupler. In order to reduce the size of the TTA and simultaneously provide 120 dB of isolation of a TX carrier, filtering has been split between the TTA and the base unit.

Industry leading TTA amplifier linearity guarantees superior immunity to intermodulation interference.


  • All tower top ports protected by internal surge suppressors.
  • Two independent Quadrature Coupled LNA's in the tower top assembly provides the redundancy needed to ensure maximum uptime.
  • Microprocessors continuously monitor amplifiers and will switch tower top LNA’s if needed.
  • Ethernet
  • Multiple Real-Time Status and Alarm Annunciation Methods:
  • Secure SNMP (v3.0) Trap Messaging (compatible with most SNMP Managers)
  • Form-C contacts
  • Front Panel Status Indicators
  • Wind loading is reduced due to the small enclosure size.
  • Available with a 16 Port Receive Multicoupler Unit.
  • Expandable as needed to 32, 40 or 48 ports.


The TTA is designed to increase the performance of a Base Transceiver Station (BTS) while ensuring reliable communications for critical Public Safety applications. This increase in sensitivity can make up for the imbalance between mobile and handheld users in critical systems.

Model NumberDescriptionPower Required
434B-83H-01-TTTA, Mini AutoQuad, 792-824 MHz, Tower Box
434B-83H-01-M-110Multicoupler Unit (MCU), 16-port, 792-824 MHz used with 434B-83H-01-T AC
434B-83H-01-M-48Multicoupler Unit (MCU), 16-port, 792-824 MHz, used with 434B-83H-01-T-48
434B-94D-01-TTTA, Mini AutoQuad, 896-902 MHz, Tower Top Box Only
434B-94D-01-M-110Multicoupler Unit (MCU), 16-port, 896-902 MHz, used with 434B-94D-01-TAC
434B-94D-01-M-48Multicoupler Unit (MCU), 16-port, 896-902 MHz, used with 434B-94D-01-T -48

Tower Top Amplifier will function up to 70°C without shutting down however, the specifications are not guaranteed outside the rated temperature range. MCU specifications values are typical unless noted otherwise.


  • TTA = Tower To Amplifier
  • MCU = Multicoupler Unit

#Note: See the datasheet for Optional Products

Graph of TTA Filtering

A steep skirted TEM bandpass filter in the tower box augmented by a ceramic filter in the base unit provide a selective 32 MHz system window.


900 MHz Composite TTA Filtering


Datasheet (PDF)

Product Specifications 
Item No434B Series
Item NameMission Critical Series, Auto Quad Tower-Top Amplifier System
Frequency Band700-800 MHz, 900 MHz
Net Gain15.0 Typ.
Rejection110 dB nominal at 776 and 851 MHz
Noise Figure2.9 dB Typ.
Total Power Dissipation17 W
TTA---Frequency Band700/800 MHz - 792-824 MHz< /br>900 MHz - 896-902 MHz
TTA---Preselector IncludedYes
TTA---Preselector Frequency Range792-824 MHz, 896-902 MHz
TTA---Type of AmplifierQuadrature Coupled (Redundant)
TTA---Amplifier SwitchingAutomatic
TTA---Type of Amplifier SwitchSolid State RF Switch
TTA Gain---Input to output of TTA22.5 dB Typ.
TTA---Noise Figure2.9 dB Typ.
TTA---LNA OIP3>43 dBm Typ.
TTA---Return Loss of all RF Ports> 14 dB
TTA---Power RequirementsPower derived from Rx Cable
TTA----Operating Temperture Range30°C to 60° C
TTA---Amplifier RedundancyAutomatic change - over
TTA---Lightning ProtectionImpulse suppressor on all external ports
TTA---Test Port IncludedYes
TTA---Coupling Test Port--Test In-Amp In30 dB
TTA---50 Ohm Termination TestControlled by base unit
TTA---Type of RF Test SwitchingSolid State RF Switch
TTA---Bypass Test ModeControlled by base unit
TTA---EnclosureWeather resistant housing designed to NEMA Standards
TTA---700 and 800 Dimensions and Net Weight8.84" x 5.77" x 6.04" / 8 lbs
TTA---900 Dimensions and Net Weight7.25" x 11.25" x 11.25" / 14.28 lbs
MCU---Frequency Band792-824 MHz, 869-902 MHz
MCU---Net Gain or Loss--RMC In to RX Out+1 dB Typ
MCU---Number of Outputs Ports16 expandable to 48
MCU---TTA ConnectorN-Female
MCU---Receiver ConnectorBNC-Female
MCU---RX-RX Port Isolation>20 dB (min.)
MCU---Test Port InputBNC-Female (Front of RMC)
MCU---Test Port OutputN-Female (Rear of RMC)
MCU---Net Gain Electronic Attenuator15 dB in 0.5 dB steps (6 dB default)
MCU---Alarm ContactsForm-C contacts
MCU---Ethernet PortRJ45 (Front panel access)
MCU---Power Requirements90-240 VAC @ 50/60 Hz or -48 VDC
MCU---Operating Temperature0°C to +50°C
MCU---EnclosureStandard EIA 19” Rack Mounting
MCU---700 and 800 Dimensions and Net Weight1 RU x 19" x 14"(45 x 483 x 356 mm) / 11.5 lbs
MCU---900 Dimensions and Net Weight1.75" x 19" x 12.25" / 9.92 lbs