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Difference between Passive DAS vs Active DAS vs Hybrid DAS

This page compares Passive DAS vs Active DAS vs Hybrid DAS and mentions difference between Passive DAS, Active DAS and Hybrid DAS.

Introduction:
It is difficult to achieve appropriate signal strength inside indoor places to meet optimum S/N ratio. This is overcome with the use of DAS (Distributed Antenna System). DAS uses single RF source and divides the same to various RF antennas installed as per requirements in indoor places for better signal distribution of cellular signal.
Refer tutorial on DAS System basics and types >>.

There are three main types of DAS systems based on elements used in their construction.
➨Passive DAS
➨Active DAS
➨Hybrid DAS

Passive DAS | Passive Distributed Antenna System

Passive DAS

Following are the features of passive DAS system as shown in the figure-1.
• It distributes RF signal using coaxial cables to multiple antennas. Sometimes it uses RF amplifier to compensate for path loss if the distribution points are further away from the source.
• RF source of up to 43 dBm power per carrier is used.
• It uses RF coax. cable with 7/8" dimension which offers low loss at the high cost per ft.
• There is attenuation of about 30 dB between source and antennas. The indoor antennas having low gain of about 2 to 5 dBi are used.
• High EIRP per antenna can be achieved compare to either active DAS or hybrid DAS.

Active DAS | Active Distributed Antenna System

Active DAS

Following are the features of active DAS system as shown in the figure-2.
• It distributes RF signal using RF coaxial cables but uses fiber/CATV along with ADC/DAC to cover longer distances. It uses power amplifier to compensate for path loss due to long distance. Hence longer range can be achieved compare to passive DAS type.
• RF source is very flexible PPC (Power Per Carrier) and can use power as low as 0 dBm.
• It uses transport mediums such as fiber for optical signal and CATV for baseband signal.
• It uses RF coax. cables with 1/2" dimension which are less expensive but offer more loss.
• Remote Power Amplifier having 5 to 15dBm PPC is used as per technology and number of channels.
• It offers lower EIRP per antenna compare to passive DAS.

Hybrid DAS | Hybrid Distributed Antenna System

Hybrid DAS

Following are the features of hybrid DAS system as shown in the figure-3.
• It is combination of both passive DAS and active DAS.
• It supports more antennas per PA compare to active DAS.
• It offers lower EIRP per antenna compare to either passive DAS or active DAS.

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