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CA3P200IB Series
Balanced FM Combiners

Rev : 01 | Rev date : 16 Nov 2021

RFS offers a comprehensive product line 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.



  • 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
  • Integrated filter and coupler design for high reliability
  • Vertical entry and exit without additional elbows
  • Natural convection cooling
  • Group delay corrector modules are available for complex multichannel systems
  • Custom options such as patching facilities and power monitoring are available

CA3P200IB16 Integrated FM Combiner Module

Technical features


Product LineCombiner Radio
Product TypeBand II (VHF) FM Balanced Combiner
Filter Type and Size3 Pole, 200mm

Electrical Specifications

Frequency RangeMHz87.5 - 108
Impedance Ω50
Minimum Channel SpacingMHz0.80.4
Narrowband Input PowerkW

3.5 (Temp Rise: 30°C)

5 (Temp Rise: 40°C)

2.4 (Temp Rise: 30°C)

3.2 (Temp Rise: 40°C)

Narrowband Insertion LossdB<0.5<0.8
Amplitude VariationdB< 0.1 to ±200 kHz< 0.1 to ±100 kHz
Group Delayns< 28 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 Connector7/8" EIA (flanged male)7/8" EIA (flanged male)
Wideband Input Connector7/8" EIA (flanged male)1-5/8" EIA (flanged male)
Output Connector7/8" EIA (flanged male)1-5/8" EIA (flanged male)
Maximum Output PowerkW515

Mechanical Specifications

Weightkg (lb)61 (135)61 (135)
Dimensions (Height or Length) cm (in)116 (46)116 (46)
Dimensions (Width) cm (in)50 (20)50 (20)
Dimensions (Depth) cm (in)72 (28)72 (28)
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