Monoblock LnbEdit

Monoblock LNB

A monoblock LNB is a specialized low-noise block downconverter assembled in a single housing that contains two independent LNBs aimed at two nearby satellites on the geostationary arc. The design lets a single dish and feed capture signals from two adjacent orbital positions, delivering two downconverted IF streams to a receiver or two tuners. This compact arrangement is popular among systems that want to receive two channels or bouquets from nearby satellites without mounting and aligning two separate LNBs.

The concept emerged as a practical solution for multi-satellite reception, balancing performance, cost, and installation simplicity. By housing two LNBs in one block, installers can reduce the amount of hardware, cabling, and mechanical adjustment required to service two satellites that sit close together in the sky. Typical European setups use a monoblock to pick up the two most common nearby beams, such as those associated with prominent broadcasters and satellite platforms in the Ku-band. For reference, the two LNBs in a monoblock are tuned to two adjacent orbital slots, and the unit is designed to produce two independent outputs that can be fed into a two-tuner receiver or routed through a DISEqC switch to a single-t tuner.

Design and operation

Basic principle

A monoblock LNB integrates two Ku-band LNBs within a single mechanical block. Each LNB receives microwave signals in the Ku-band (roughly 10.7 to 12.75 GHz) and converts them to a lower, usable IF signal for downstream reception (typically in the 950–2150 MHz range). The two LNBs share a common mounting geometry and feed horn but have separate RF paths and IF outputs, allowing the receiver(s) to independently tune to the different satellites.

Common configurations

Dual-output monoblock: The unit provides two separate IF outputs, one from each LNB, allowing a modern receiver with two tuners to select both satellites without a separate LNB mount. Some installations route both outputs into a single multi-tuner receiver, while others may use a DISEqC switch to alternate feeding a single tuner when only one tuner is active at a time.
Fixed separation: Monoblocks are designed for a fixed angular separation between the two satellites. The typical separation is dictated by the chosen satellite pair (for example, widely used European pairs such as Astra at 19.2°E and another nearby slot). The fixed geometry means the dish must be aligned to accommodate both signals simultaneously, which is the core advantage of a monoblock in terms of ease of installation.

Frequency bands and performance

Monoblock LNBs operate in the Ku-band and share the same core performance metrics as single LNBs, including noise figure, gain, and linearity. The noise figure is typically in the low dB range, and the overall system gain is optimized to preserve signal quality across both channels. Because each LNB has its own local oscillator, the unit downconverts the respective signals with two slightly different LO frequencies, enabling the two independent IF outputs that the downstream receivers expect. The two channels are processed in parallel, but their demodulation depends on the receiver’s capability to handle DVB-S or DVB-S2 signals as appropriate.

Output and switching

Two main usage patterns exist: - Two-tuner reception: A receiver with two tuners can independently lock onto channels from each satellite using the two IF outputs of the monoblock. - Single-tuner reception with a switch: If a single-tuner receiver is used, a DISEqC switch may be employed to route one satellite through the available tuner at a time, or the system may rely on a dual-output LNB and a separate switch arrangement.

In many installations, the monoblock sits at the focal point of the dish, and the control scheme leverages standard satellite standards such as DVB-S and DVB-S2, depending on broadcaster and service. The feed design prioritizes stable polarization handling to minimize cross-polarization interference and maintain solid signal margins in variable weather.

Installation and practical considerations

Dish size and suitability: Monoblock LNBs work well on mid-sized to larger dishes (for Ku-band reception) because the dish geometry must accommodate two adjacent beams. On very small dishes, the available aperture may not provide satisfactory performance for either or both satellites.
Alignment and skew: Since the unit targets two nearby satellites, precise mechanical alignment to the arc is essential. The dish must be positioned with appropriate tilt and skew to optimize both signals simultaneously.
Weather resistance: Outdoor exposure requires weatherproof housings and sealing. Modern monoblock LNBs are designed to resist moisture and temperature swings, with robust connectors for reliable long-term operation.
Cabling and power: The LNBs are powered through the coaxial cables feeding the IF outputs, sometimes sharing power via a single supply. If separate power or signaling is required for each LNB, installers must ensure compatibility with the receiver and any DISEqC controllers in the chain.
Standards and compatibility: For viewers using contemporary digital TV services, compatibility with DVB-S2 is important for efficiency and bandwidth. When choosing a monoblock, buyers often consider whether the unit supports the current broadcast standards and can interface cleanly with the receiver(s) in use. See DVB-S and DVB-S2 for related standards.

Market and use cases

Monoblock LNBs are a pragmatic choice for households and small commercial setups that want to receive two adjacent satellites without the clutter and expense of two separate LNBs and mounts. They are particularly common in regions where broadcasters rely on a pair of nearby satellites to deliver a wide channel lineup, and where installation simplicity is valued. Availability varies by region and by vendor, with different models offering slightly different separation angles to match specific satellite pairs. When selecting a model, operators consider the intended satellite pair, dish size, and whether the system will primarily use a dual-tuner receiver or a single-tuner setup with a switch.

In practice, monoblocks are part of a broader ecosystem of satellite receiving hardware that includes LNBs, satellite dishs, and DiSEqC switching hardware, all designed to maximize the efficiency of multi-satellite reception while maintaining reliability across a range of environmental conditions.