Comtech EF Data LCS-4 L-Band Combiner Switch

  • 4-way L-Band combining
  • 4-Way L-Band splitting
  • Hot swap power supplies
  • Manual and Remote operations
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LCS-4 Combiner Switch

The Comtech EF Data LCS-4 Combiner Switch is an indoor unit that provides combining / splitting for L-Band modems, plus it operates as a redundancy controller for RF switches located at the antenna. The unit's features include:

  • 4-way L-Band combining for modulators
  • 4-way L-Band splitting for demodulators
  • L-Band Interface to ODU/BUC and LNB
  • 1:1 controller for BUC redundancy
  • 1:1 controller for LNB redundancy
  • Hot swap power supplies replaceable from the front
  • Options for redundant BUC power supplies
    • 24 VDC at 100 W
    • 48 VDC at 180 W
  • BUC PS supports up to 10 W C-Band and 8 W Ku-Band
  • High stability internal 0.02 ppm 10 MHz reference


The LCS-4 Combiner Switch resides between the L-Band modems and outdoor BUCs and LNBs. A built in 4-way combiner sums L-Band modulators and delivers traffic to the online BUC while powering the redundant BUC and maintaining it in active standby. Similarly, the L-Band signals from the online LNB are delivered to L-Band demodulators by a built in 4-way splitter, while the offline LNB is powered and ready in active standby. A block diagram of the LCS-4 is provided.

The inputs and outputs of the Combiner Switch are L-Band (no frequency translation). DC power and 10 MHz are inserted and sent to the BUC and LNB up the center conductor of optional IF cables. Two of the Tx combiner inputs accept FSK from the modulator and pass it through for monitor and control of BUCs that support FSK operation.

The LCS-4 continuously monitors the BUCs and LNBs for faults and independently protects them. When a fault is detected the signals are transferred to the standby path.

In the event that both BUCs (or both LNBs) are faulted, switchover is inhibited until one of the faults is cleared.


Operation of the unit is normally automatic, however, the unit is also controlled using a front panel keypad or an RS- 232 / 485 remote port.

When operated from the front panel the following controls and LEDs are provided:

  • AUTO / MAN selects automatic or manual operation
  • CAL stores nominal BUC and LNB current for fault limits.
  • BUC A/B online
  • LNB A/B online
  • Individual DC Power ON/OFF for each BUC and LNB
  • Separate 10 MHz ON/OFF for each BUC and LNB
  • Status LEDs for BUC-A, BUC-B, LNB-A and LNB-B, the LCS-4 and Prime Power A and B


The LCS-4 delivers a 10MHz reference signal to the BUC and LNB through interconnecting coaxial cables. Normally, the internal 0.02ppm oscillator is used, but the unit will also phase lock to an external 10 MHz source. The 10MHz signal also is internally buffered and delivered to 4 BNC connectors for use by modems (not required) or other earth station equipment.


Two features built into the LCS-4 reduce overall system cost:

  • The 0.02 ppm reference in LCS-4 allows the use of LBand Modems with lower stability (to 1.0 ppm, depending upon the modem) while maintaining overall frequency accuracy.
  • The LCS-4 is available with single or redundant BUC power supplies eliminating the need for a BUC power supply in the modem.

The cost advantage improves as the number of modems increases.

More Information
Weight 17.0000
Country of Manufacture United States
Manufacturer Comtech EF Data
Input Power 100 - 240 VAC
Warranty 2 Years
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101 Eagle Road Building 7. Avon, Colorado. 81620.
T : (970)-748-4250.