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CA3P400IB Series
Balanced FM Combiners

Rev : 02 | Rev date : 16 Nov 2021

RFS offers a comprehensive range of FM combiners to suit all common FM combining applications. The balanced, or constant impedance, bandpass design provides the best possible frequency response and specifications, and is ideal for large multi-station channel combiners or when frequency spacings are very close.

 

A balanced module consists of a balanced pair of bandpass filters, two 3dB couplers and a balancing load. The narrowband input corresponds to the filter resonant frequency, whereas the wideband input can be any other frequency in the 87.5 - 108 MHz band. The wideband input signal loss is very low because it does not pass through the bandpass filters. Modules can therefore be cascaded to form a multichannel combiner. The modular design enables extra channels to be easily added at a future date.

 

FEATURES / BENEFITS

  • Compact size with small footprint for design power rating
  • Can be field retuned to any frequency in the 87.5 - 108MHz band
  • Invar temperature compensation for stable operation
  • Vertical entry and exit without additional elbows
  • Natural convection cooling
  • Group delay corrector modules are available for complex multichannel systems
  • Integrated coupler and filter design for high reliability
  • Custom options with U-Links, motorised coaxial switches, monitoring systems, etc. are available
     


Balanced FM Combiner with Integrated Couplers on 3 Pole 400mm Filters

Technical features

Structure

Product LineCombiner Radio
Product TypeBand II (VHF) FM Balanced Combiner
Filter Type and Size3 Pole, 400mm

Electrical Specifications

Frequency RangeMHz87.5 - 108
Impedance Ω50
Minimum Channel SpacingMHz0.80.60.4
Narrowband Input PowerkW

9 (Temp Rise: 30°C)

12 (Temp Rise: 40°C)

7 (Temp Rise: 30°C)

10 (Temp Rise: 40°C)

5.5 (Temp Rise: 30°C)

7.5 (Temp Rise: 40°C)

Narrowband Insertion LossdB<0.3<0.4<0.48
Amplitude VariationdB< 0.1 to ±200 kHz< 0.1 to ±150 kHz< 0.1 to ±100 kHz
Group Delayns< 28 to ±100 kHz< 135 to ±100 kHz< 390 to ±100 kHz
Wideband Input Insertion Loss dB≤0.1
Return Loss dB>30
Isolation - N/B to W/BdB>32
Isolation - W/B to N/BdB>50
Input Connector3-1/8" EIA (unflanged female) (Note 1)
Wideband Input Connector3-1/8" EIA (unflanged female) (Note 1)
Output Connector3-1/8" EIA (unflanged female) (Note 1)
Maximum Output PowerkW50

Mechanical Specifications

Weightkg (lb)145 (230)
Dimensions (Height or Length) cm (in)130 (51)
Dimensions (Width) cm (in)124 (49)
Dimensions (Depth) cm (in)91 (36)
CoolingNatural convection

Temperature Specifications

Maximum Operating Temperature °C (°F)80 (176)
Ambient Temperature Range °C (°F)-5 to 55 (23 to 131)
Maximum Temperature Rise °C (°F)40 (104)
Humidity%95, non-condensing

 

 


External Document Links

Notes

  • Note 1. Other connectors are available on request