955 Series Constant Impedance FM Combiner Module

The ERI Model 955 Series Constant Impedance FM Combiner Modules provide stable high performance combining system for medium power multi-station FM combining systems.

Description

ERI’s 955 sERIES constant impedance combiner module is modular in construction and is designed so that additional stations may be added in the future. The frequency of the additional stations may be located anywhere within the FM broadcast band 2.0 MHz (0.8 MHz with 955-8) or more from any other system frequency.

All ERI filters are temperature compensated to enable the system to meet intermodulation product specifications at cold start as well as at normal operating temperature. The individual resonant cavities in the unit are made almost entirely of aluminum and copper.

The filter cavities are sized to provide low insertion loss resulting in minimal temperature rise and reduced transmitter power loss. The individual cavities are loop coupled so that each filter bank can be optimized for the particular application required and can be retuned in the field if necessary. The filters are provided with an integrated floor mounting frame, that can suspended from a ceiling or wall mount, with appropriate optional mounting hardware.

Features and Benefits

  • Light weight aluminum cavity construction
  • Factory tuned to customer’s specified channel, yet can be easily field converted to any FM channel
  • Minor adjustments of cavity resonant frequency can be made during full power operation of filters
  • High stability temperature compensated cavities
  • ERI filters are loop coupled and fixed with bolted connections to couple cavities
  • Loop coupling provides an adjustment (without disassembly) at the input and output of each cavity
  • Ability to change frequency quickly and with a minimum of disassembly
  • Filter can be easily broken down for shipment and placement
  • Optional non-adjacent coupling and group delay compensation available
  • Easily assembled floor standing units (hardware for ceiling suspension available on request

Specifications

  • Band:
    FM
  • Frequency Range:
    88 to 108 MHz
  • Number of Cavities:
    Thre (3) or Four (4)
  • Power Handling:
    9 kW convection cooled
  • 16 kW with forced air cooling
  • Mounting Configuration:
    Floor or Ceiling attachment
  • Insertion Loss:
    < 0.4 dB at ±200 kHz
  • VSWR:
    < 1.1:1 at ±200 kHz
  • Group Delay:
    < 75 nsec overall variation ±150 kHz
  • < 25 nsec with optional group delay correction

Models Available

  • 955-6
    ERI Model 955-6 Constant Impedance FM Combiner Module, convection cooled
  • 955-6A
    ERI Model 955-6 Constant Impedance FM Combiner Module, with optional forced air cooling
  • 955-8
    ERI Model 955-8 Constant Impedance FM Combiner Module, convection cooled
  • 955-8A
    ERI Model 955-8 Constant Impedance FM Combiner Module, with optional forced air cooling

Product Brochures

955-6 Constant Impedance FM Combiner Module Product Brochure

Download File

955-8 Constant Impedance FM Combiner Module Product Brochure

Download File