FBC with Unicable/JESS: eight SCRs over one cable

For eight independently selectable transponders, give each of the eight demodulators its own user band. One suitable coaxial cable is sufficient. The satellite installation must provide those user bands and assign them to this receiver.

Wiring and prerequisites

Recommended simple arrangement for one shared Unicable feed: one cable into A, B–H connected internally through A. The second socket stays empty, but logical tuner B remains usable. Enlarge wiring diagram ↗

Before starting, obtain the LNB/multiswitch manufacturer and model, supported protocol, assigned UB numbers and their frequencies, available satellite positions and a PIN if required. Ask the operator for these details in a shared installation. A free demodulator does not prove that a user band is available.

EN50494 (Unicable/SCR) supports up to eight user bands; EN50607 (JESS/Unicable II) allows more, up to 32. The actual installation may provide fewer. Match both protocol and equipment type to the installation. A 32-UB output does not turn an eight-way FBC block into 32 demodulators. Background: JULTEC on channel-stacking systems, Inverto on one-cable distribution.

Step 1: configure root tuner A

Menu → Setup → Reception → Tuner configuration → Tuner A

Select Configuration mode = Advanced.
Select an available satellite position and assign it to an LNB entry. The example assigns Astra 19.2°E to LNB 1.
Set the LNB/LOF type to Unicable / JESS.
Choose the actual equipment type: Unicable LNB, Unicable matrix or appropriate user-defined settings. An external distribution matrix is different from an SCR output directly on an LNB.
Choose manufacturer and model to obtain the corresponding frequency/protocol settings. Do not select a merely similar product name.
Select A’s assigned SCR/user band and matching frequency.
A receives the cable directly. Do not unnecessarily connect A through another tuner.

Advanced Unicable configuration of the first FBC tuner — Configured installation example: Astra, LNB 1 and a Unicable matrix. These values describe the example system, not defaults suitable for every installation. Open original image ↗

Manufacturer, Unicable matrix, SCR and frequency for tuner A — SCR and frequency form a pair. This is the user-band frequency on the cable, not the satellite transponder frequency. Open original image ↗

Step 2: give B–H their own SCR through A

Open tuner B and configure its advanced Unicable settings. For internal tuners C–H, select FBC SCR (Unicable/JESS).
Configure the same installation and the satellites it actually provides.
Enable Connected through another tuner, unless the dialog already enforces it, and select Connected to = Tuner A. Part of this connection may be preset depending on hardware and dialog state.
Give every tuner its own SCR number and matching frequency. Do not copy the first assignment unchanged seven times.
Save and compare all eight assignments once more.

Logical tuner B internally connected through A to the shared Unicable feed — B has its own SCR but receives the signal internally from A's feed. No additional cable is needed in the second satellite socket. Open original image ↗

Individual SCR assignment for internal FBC tuner C — An internal demodulator also receives a unique assignment. FBC automatic alone would not provide this allocation. Open original image ↗

Example: eight assigned user bands

This table belongs to the TechniRouter 9/1x8 profile used by the example installation. All eight bands were assigned exclusively to this receiver. Use the correct table for a different LNB or matrix.

Tuner	Displayed SCR	Frequency	Signal path
A	1	1284 MHz	Cable directly into A
B	2	1400 MHz	Internally through A
C	3	1516 MHz	Internally through A
D	4	1632 MHz	Internally through A
E	5	1748 MHz	Internally through A
F	6	1864 MHz	Internally through A
G	7	1980 MHz	Internally through A
H	8	2096 MHz	Internally through A

Tuner H with SCR 8 at 2096 MHz — The eighth reception path also has its own user band. No SCR is reused within this shared branch. Open original image ↗

Some manuals or software number bands from 0, others from 1. Compare the numbering and frequency together. A band called UB 0 in one system may appear as SCR 1 in another; this does not mean that the next higher band should be selected arbitrarily. Profile source: OpenATV unicable.xml.

Other options and their purpose

Option / term	Purpose
Satellite / LNB assignment	Links an available satellite position to its LNB entry. The installation determines which positions exist.
Unicable configuration mode	Selects a known LNB/matrix table or user-defined values
Priority	Influences preference for this LNB/reception path during tuner selection; initially leave Auto. It does not replace SCR allocation.
Externally powered	Enable only when a power inserter or external supply actually powers the Unicable device.
Unicable position	0 derives the position from the LNB number and device profile. Explicit values 1–64 are intended for appropriately reprogrammed devices; this is not the 19.2°E orbital position.
Tuning algorithm	Adjusts SCR timing, for example with several SCR devices and suitable outlets. Start with the default selection.
Manufacturer / model	Supplies frequency and protocol defaults for the actual equipment
SCR / user band	Unique reception-path address on the shared branch
Frequency	The matching SCR centre frequency in MHz; not interchangeable at will
Channel / protocol in user-defined settings	Must match the installation’s EN50494/EN50607 operation
PIN	Use only when the installation protects a user band with a PIN and provides the correct PIN
Connected through / connected to	Describes the real shared cable and internal FBC signal route
Increased voltage / power-on delay / repeats	Special supply and switching adjustments; retain defaults initially and change only according to installation requirements
DiSEqC / position mapping	Must match the actual multi-satellite installation. A second position offered by a profile does not prove that two satellites are connected.

Not every field appears in every combination. Visibility depends on equipment type, configuration mode and hardware. See the reception configuration options for the wider catalog.

Two cables, splitters and other receivers

One suitable SCR feed is sufficient for the eight tuners shown here. Two cables can be useful when they provide different reception installations or separate SCR outputs. Assign each demodulator to the root tuner actually supplying it and to that feed’s user bands; do not indiscriminately connect everything through A.

When several receivers share one SCR output, user-band assignments must remain unique across all those receivers. A second splitter output does not create a separate numbering domain. Truly independent SCR outputs may reuse numbers if the manufacturer’s design permits it.

Use SAT/SCR-compatible splitters with the required frequency range and intended DC/control-signal paths. Follow the equipment specifications for isolation and power supply. Do not arbitrarily connect two powered outputs together. This differs from a conventional universal-feed Y splitter.

Troubleshooting

Symptom	First checks
One channel works, concurrent recordings interfere	Duplicate SCR on this receiver or another receiver sharing the branch
Only A works	B–H lack individual SCRs, their internal connection is wrong or frequencies do not match
One particular tuner never locks	Its SCR/frequency, assigned availability, protocol and PIN if used
Tuners remain unused after switching to Unicable	C–H still set to FBC automatic instead of FBC SCR
Only one satellite works	Actual available positions and mapping; a model profile cannot create reception
Failures when several tuners start	Supply, cable, outlets, splitters and voltage drop before special timing adjustments

Use different transponders simultaneously for a practical test. Several channels on one transponder do not prove eight independent paths. See testing FBC.

Menu and automatic-allocation logic: OpenATV NimManager, FBC core.