Manifold Combiners
Cascade of multiple filters connected to a common output transmission line (Manifold). COM-TECH pioneered this technique for Broadcast TV and FM applications and enhanced its versatility with Adjacency Combination. Cost-effective solution to combine numerous frequencies. Available for low power levels, with configurations from 2 to 5 Poles, and for the UHF, VHF B.III, and FM operating bands.

Starpoint Combiners
Multiple filters connected to a common junction. Cost-effective solution to combine a limited number of frequencies. Adjacency Combination is generally not possible. Available for a wide range of power levels, with configurations from 2 to 8 Poles, and for the UHF, VHF B.III, VHF B.I, DAB, and FM operating bands.

Balanced Combiners
Balanced structure of two identical Bandpass Filters and two Hybrid Couplers, with one Narrowband (filtered) constant impedance input and one Wideband (non-filtered) input. Provides maximum versatility and performance, permits to create chain-combiners, and allows Adjacency Combination. Available for a wide range of power levels, with configurations from 2 to 8 Poles, and for the UHF, VHF B.III, VHF B.I, DAB, and FM operating bands.

Full-Band Tunability
COM-TECH Bandpass Filters and Combiners are fully tunable across their operating band, in compliance with all worldwide standards and regulation masks. They are engineered for easy retuning using a standardized, limited set of tools. Customer-defined tunings are available upon request.

Temperature Stabilization
COM-TECH Bandpass Filters and Combiners feature an advanced temperature stabilization, achieved through 3D EM and fluid dynamic simulations, specialized materials, and rigorous environmental and laboratory testing.

DC-Short Protection
COM-TECH Bandpass Filters and Combiners include built-in protection against antenna lightning discharges, implemented through a solid DC-short circuit to ground on both input and output couplings.

Modular Frame System
COM-TECH Combiners are housed in modular frames that ensure complete flexibility and scalability. This design allows easy extension, integration, maintenance, and shipment. Combiners can be shipped as separate modules and assembled on-site. The system integrates seamlessly with COM-TECH Directional Couplers, Patch Panels, and other components.

Modular Connector System
COM-TECH products feature an innovative and proprietary connector architecture that allows a wide range of connections on the same unit. This solution provides exceptional flexibility, allowing quick customization and easy connector replacement—even at a later stage, by the Customer.

10-Year Warranty
COM-TECH products are renowned for reliability. All passive products are guaranteed for 10 years, while active products (e.g., forced air cooling) and resale items are guaranteed for 2 years.

Eg. DF6D200R/4:

• DF: Product Series (DB, DM, DF)
• 6: No. of Poles (6, 7, 8…)
• D: Response (X=XLine, D=DualCross, E=Cross Coupling, A=A.N.T., P=All Pole)
• 140: Cavity Size (140, 200…)
• R: Operating Band (C=UHF, B=VHF B.III, A=VHF B.I, R=DAB, F=FM)
• /4: Number of Inputs (2, 3, 4…)

DF6D200R/4: DF Series, 6-Pole, DualCross, 140 mm, DAB, 4 Filtered Inputs (plus one Wideband
SF8D200B/3: SF Series, 8-Pole, DualCross, 200 mm, VHF B.III, 3 Inputs
MX4P20C/5: MX Series, 4-Pole, All Pole, 20 mm Cavity Size, UHF, 5 Modules

Balanced Combiners deliver unmatched felixibility, allowing scalable solutions that allow Chain-Combiner configurations.

Wideband Port
The Wideband input delivers a unique versatility to Balanced Combiners, allowing to expand their combining possibility, cascading multiple Balanced Combiners to create a chain configuration of n modules that features:

• One Wideband input (at the beginning of the chain), which can further be connected to another Combiner (or Bandpass Filter) to integrate additional frequencies; or terminated with a Load, preserving the option for future system expansion
• n Narrowband inputs (one per module in the chain)
• One Antenna Output (at the end of the chain, combining the frequencies of the Wideband input and Narrowband inputs)

Extension
The Wideband input can be optimized in two ways:

• Frequency-Optimized: Return Loss and performances optimized for specific frequencies, but limited extension beyond optimized frequencies
• Whole-Band Optimized: Return Loss balanced across the entire band, allowing broader extension, but with moderate limitations. MultiStep technology ensures superior performance, achieving near-optimal Return Loss across the full band.

A Balanced Combiner can be extended, adding a new Combiner (or Filter) in two possible positions:

• In the Wideband input side: the existing Balanced Combiner must have its Wideband port unused, able to accept the new frequencies, and withstand the increased power. The new combiner can be a Starpoint, Manifold, Balanced (or a single Filter), and it generally smaller. The integration requires reduced mechanical work.
• In the Antenna output side: the new Combiner type must be Balanced, is generally bigger, and needs to be optimized to accept the existing frequencies. The integration requires significant mechanical work.

Performances
Tuning data reported on the Datasheets refers to one single Balanced Combiner module. The performances of Chain Combiners are affected by different factors, such as: number of combined frequencies, frequency order and assortment, and Adjacency.

1. Wideband Power
COM-TECH chain combiners are dimensioned to withstand the overall output power, even in Wideband mode (the Wideband input power having a double impact on hybrid couplers), thus making the calculation of the Wideband Input power extremely easy:
WB Input Power = Maximum Output Power – Sum of NB Input Powers

2. Peak Voltage
The composition of several digital signals undergoes to a complex statistical process, which deviates from the theoretical voltage composition. COM-TECH chain combiners are dimensioned to sustain the increased voltage peaks caused by the vector composition of several signals (up to 10 frequencies).

3. Insertion Loss
The overall insertion loss of a Balanced Combiner chain is the sum of the insertion loss of the single module, increased by the sum of the Wideband insertion losses of the succeeding modules:
Overall I.L. = Single Module I.L. + (n x Wideband I.L.)

4. Return Loss
The combination of several Balanced Combiner modules involves a derating of the overall Return Loss (indicative values for frequency-optimized Wideband tuning):

• 1 Module: 26 dB (VSWR 1.11)
• 2-5 Modules: 25 dB (VSWR 1.14)
• 6-8 Modules: 24 dB (VSWR 1.16)
• 9-10 Modules: 23 dB (VSWR 1.18)

COM-TECH offers a specialized Retuning Training Program designed to equip technical teams with the skills to independently and efficiently retune Bandpass Filters and Combiners. This modular program combines theory with hands-on practice and is tailored to each Customer’s needs—including product selection, learning objectives, and preferred training location.

Modules & Certification
The program covers the complete range of COM-TECH components, and is divided into different modules:

• Bandpass Filters (All-Pole, Cross Coupling, DualCross, XLine)
• Manifold Combiners
• Starpoint Combiners
• Balanced Combiners

Each module provides theorical and practical experience.
Upon completion, all attendees receive a Certificate of Participation, specifying the modules completed.

Facilities & Support
The training can be conducted either at COM-TECH’s facilities – the preferred option, offering access to the full product range, or On-site at the Customer’s premises – for convenience and operational continuity.
Tuning Instructions are available for all COM-TECH Bandpass Filters and Combiners, and a complete toolkit, including all necessary tools for retuning, is available upon request.