FBC with a universal LNB: one cable, two cables, multiple positions

A conventional universal LNB supplies one selected satellite plane per subscriber feed. FBC can receive several transponders from that plane. It cannot simultaneously request the other three planes through that same cable.

The four satellite planes

Plane	Polarisation	Band	Typical universal-LNB control
VL	Vertical	Low band	13 V, 22 kHz off
HL	Horizontal	Low band	18 V, 22 kHz off
VH	Vertical	High band	13 V, 22 kHz on
HH	Horizontal	High band	18 V, 22 kHz on

Low/high refers to the satellite frequency band, not HD/SD or picture quality. A universal Ku-band LNB typically uses local oscillator frequencies of 9750/10600 MHz and a band switch at 11700 MHz. OpenATV selects voltage and tone according to the transponder requested. Normal universal LNBs need no manual adjustment of these defaults; other LNB types require their own specifications.

One universal cable

Example: A selects HL. Additional demodulators can receive other HL transponders; VL, VH and HH are not simultaneously available through this feed. Enlarge wiring diagram ↗

1. Connect the subscriber cable to the first satellite input of the FBC block. Switch off and disconnect power before moving coaxial cables.
2. Open Menu → Setup → Reception → Tuner configuration and select its root tuner A.
3. For a direct Astra feed: Configuration mode = Simple, Mode = Single, Satellite = Astra 19.2°E. A direct feed without a DiSEqC switch needs no DiSEqC command.
4. Use the offered internal connection from B to tuner A if B is to share the single feed. Do not use Equal to A to describe a second independent feed. Without an external or supported internal feed, B remains Not configured and contributes no reception path.
5. Leave internal tuners C–H on FBC automatic. They need no individual satellite lists or SCR numbers for this connection type.
6. Save and test a suitable service. Internal allocation takes place automatically during reception.

Unsaved menu example for a conventional Astra feed. The actual test installation uses Unicable and was not changed to universal reception for this image. Open original image ↗

C–H: FBC automatic assigns available reception paths internally. This setting does not allocate Unicable user bands. Open original image ↗

Example of a limit: A recording holds A on HL. Another HL transponder can use a free internal demodulator. A service on VH cannot be received at the same time through this single conventional feed, even if unused demodulators remain.

Two independent universal cables

Two feeds allow up to two selected planes at once. The block still contains eight demodulators in total. Enlarge wiring diagram ↗

Suitable sources include two outputs of a Twin/Quad LNB or two subscriber outputs of a conventional multiswitch. A normal Y splitter does not turn one feed into two independently switchable planes.

1. Connect two independent subscriber feeds to the two satellite inputs.
2. Configure A for the installation.
3. Configure B accordingly. If both feeds offer the same satellites with the same switch assignments, Equal to tuner A is suitable. B remains an independently controlled input.
4. Leave C–H on FBC automatic and save.

Unsaved example: Equal to A fits a second independent feed with the same reception configuration. It means neither loop-through nor a second SCR. Open original image ↗

Equal to copies the reception description. Connected to / loop-through describes a shared signal path with restrictions. A supported internal connection allows B to share A’s feed; it does not create a second independently selectable plane.

Even two cables cannot supply all four planes simultaneously. Internal demodulators are assigned to the active reception requirements; there is no need for a fixed “four for A, four for B” allocation. A DiSEqC multiswitch may additionally select a satellite position per subscriber feed. Each conventional feed is then limited to its selected position and plane.

Two fixed positions without a DiSEqC switch

Two separate fixed feeds: an input cannot switch to a satellite whose LNB is connected only to the other input. Enlarge wiring diagram ↗

• A: Simple → Single → Astra 19.2°E.
• B: Simple → Single → Hotbird 13.0°E.
• C–H: FBC automatic.
• Without a switch in either feed, do not invent a DiSEqC port. B is not “Equal to A” here, because the satellites differ.

Both positions can be received concurrently, within the currently selected plane of each input. For several positions through one conventional feed, see DiSEqC and AutoDiSEqC.

Fixed dish plus separate motor dish

Schematic wiring example. The motor dish is a separate antenna and was not moved during this documentation capture series. Enlarge wiring diagram ↗

Configure A for the fixed position. Give B its own motor/USALS configuration with the correct location or DiSEqC 1.2 positions. C–H remain automatically allocated for these conventional feeds.

Moving the motor changes the position of the entire motor dish. Recordings and internal demodulators using that dish are affected. The separate fixed dish on A remains independent. Two cables from the same motor dish can supply different planes, but never different orbital positions at the same time.

Do not confuse universal, Unicable and wideband feeds

Do not assign imaginary SCRs to a universal LNB. Conversely, with Unicable, do not leave internal tuners on conventional automatic settings when eight independent SCR paths are required. Wideband outputs carrying permanent H/V are not a normal Twin universal connection either; they require matching hardware and installation settings.

The conventional diagrams are general configuration examples. Native example menus were opened without saving, preserving the working Unicable installation. Source: OpenATV tuner configuration, tuner and LNB configuration.

Manufacturer example of an internal connection with one conventional feed: GigaBlue FBC configuration.