LNB types, Ku/C band and LOF

The LNB sits on the satellite dish. It receives the satellite signal and converts it to a lower frequency range that the coaxial cable carries to the receiver. The LNB settings describe this conversion and its control.

LNB designs

Type	Connection and purpose
Single	One switchable subscriber output for one conventional reception path
Twin	Two independent subscriber outputs
Quad	Four independent switchable subscriber outputs
Quattro	Four fixed planes: vertical/low, horizontal/low, vertical/high, horizontal/high. Connect to a suitable multiswitch
Monoblock	LNBs for different positions with a built-in switch. Port mapping and angular spacing must match
Unicable LNB	Outputs requested transponders on allocated User Bands; requires SCR configuration
Wideband	Usually separate wideband H and V outputs. Requires a compatible matrix or explicitly supported input; not a direct universal-LNB replacement
Optical distribution	Configure for the electrical converter’s receiver output, such as legacy or SCR

“Single” on an LNB describes its subscriber outputs; “single tuner” describes a receiver frontend. A Quad LNB does not turn one tuner into four.

A Quattro requires the correct mapping of all four planes. A direct subscriber normally uses a switchable output. Enlarge wiring diagram ↗

Ku band, C band and polarisation

Typical European domestic Astra/Hotbird installations use Ku band. An ordinary universal Ku LNB uses two local oscillator frequencies for this range. C band is lower and requires different LNB parameters, often larger dishes, and linear or circular polarisation depending on the service. C band is unrelated to DVB-C cable television.

Linear: horizontal/vertical (H/V). Circular: left/right (L/R). Match the LNB and satellite service. Changing a menu entry cannot turn an H/V LNB into a circular LNB.

LOF and control signals

Field	Meaning / typical universal Ku example
LOF/L	Low-band local oscillator, commonly 9750 MHz
LOF/H	High-band local oscillator, commonly 10600 MHz
Threshold	Band switching boundary, commonly 11700 MHz
Voltage	Typically about 13 V for V and 18 V for H; the installation and LNB determine its use
22 kHz tone	Normally off for low band and on for high band on universal Ku
Increased voltage	A supply-related special setting; not an SNR or aerial gain control

These three frequencies are not universal defaults for every LNB. For C band, wideband or special oscillators, select the matching type or User defined with manufacturer data. A typical Ku low-band example is 11000 MHz satellite frequency − 9750 MHz LOF = 1250 MHz intermediate frequency. Enter the satellite frequency in a service scan, not the intermediate frequency by mistake.

If only low/high band or H/V works, check voltage, tone, Quattro plane wiring and LNB parameters. A full scan cannot correct a swapped plane.

Source revision: OpenATV NimManager.py.