The GPR3000 unit is designed for use with block upconverter modules operating in the C, Ku or DBS satellite frequency bands.

The Unit contains single or separate dual circuitry, each providing an L band route for the transmit data signals, 10MHZ signals from a high stability oven controlled crystal oscillator used to lock the block up converter (BUC) to, and a +24V DC supply to power the BUC. All of these signals are inserted onto the ‘composite’ output for connection to the cross-site cables.

Warning – the composite output connector from the GPR3000 has +24V DC supply between pin and body of the connector. Care must be taken if test equipment is connected to this port.

System Block diagram:

GPR3000 Power Reference Unit:

The circuitry is housed within a 2U 19 inch rack unit having visual indications on the front panel for the internal circuitry and clean contact alarms via a 25 pin D type connector on the rear.

Internal circuitry monitors the following status for each circuit:

Block up converter current. If the Block Upconverter looses lock with the 10MHZ crystal it will Mute its output. If this happens the current drawn from the GPR3000 will reduce from approximately 1.2A to 300mA and generate a ‘BUC’ alarm within the unit.

The crystals within the unit also provide alarms when the oven temperature is not within specification (this will happen for a while after switch on) and if the RF power on the 10MHz signal is low.

The Power supplies within the unit are also monitored and in the event of a failure will produce a visual and clean contact alarm.

Visual Indications:
LED on front panel

The 10MHZ crystal frequency has electrical and mechanical adjustment. In the event of the crystal aging it may be necessary to adjust the oscillator frequency. A potentiometer mounted on the rear panel of the unit will electrically adjust the frequency of oscillation, however the accuracy of the crystal will be as good or better than the measurement equipment and it is therefore recommended to monitor the ku band signals when adjusting the potentiometer.

When delivered the adjustment is set to its central position, it is not expected that physical adjustment will be needed but in this eventuality, access can be obtained to the crystal body by removing the top cover of the unit.

It is recommended that the transmit frequency is checked and adjusted every 6 months. In the event that, because of the nature of the service, it is not possible to measure the transmit frequency Eutelsat and Intelsat will help in ensuring that the transmit frequency is correct by monitoring the signals on the satellite and advising whether adjustment is necessary. Call the CSC in Eutelsat on +33 1 45570666 for support.

  
 TPR3000 Alarm Connections

Specification:
Physical:
Size:                                     19 inch rack unit, 2U, 350mm deep.
Weight:                                 2.5 Kg.

Power:
Mains:                                   220-240V AC
Consumption:                         25W (typical)

Indications:
Front panel:                           Status LEDs.
Contacts:                              Form C contacts for alarm conditions.

Reference (10MHz):
Frequency stability /day:           1 x 10^-9
Phase Noise:                               dBc/Hz
Offset     10Hz.                     -120
              100Hz.                    -130
              1kHz.                      -150
              10kHz.                    -155
              100kHz.                  -155
10MHz Power                         +3 to +7dBm

L Band:
Frequency                             950 -1450MHz
Through Loss                          3-5dB.

DC supply power:
+24 V @ 2A (BUC supply)

Connections:
Mains:                                      IEC.
L band i/p 1 & 2:                      N type ‘F’
L band o/p 1 & 2:                     N type ‘F’
Alarms:                                     25W D.