Maximum Power; Figure 54. Initial Power In Probe And Ibuilder - iDirect evolution x1 Installation Manual

Overview
After the Satellite Router has been acquired for the first time and the UCP process is
operating, the Network Operator records the reference carrier power level as a clear-sky
benchmark for the remote site. The Transmit Power Relative to the Reference Carrier is the
Satellite Router IF output power that would be used if the remote site were to close the link
at the required C/N using a carrier with properties identical to those defined for the
0
reference carrier.
The Transmit Power Relative to the Reference Carrier is displayed on the iMonitor Probe
screen. The Network Operator notes the transmit power level after acquisition and uses it as
the starting point for determining the initial power setting in iBuilder. The procedure for
bringing the remote into the network for the first time and determining the transmit power
level is contained in "Initial Acquisition" on page 92.
Figure 54 shows the related sections of the iMonitor Probe (left) and the iBuilder Remote
Information tab (right) after commissioning. In the figure, the Satellite Router is in the
network and is currently transmitting (under UCP control) at -21.78 dBm relative to the
configured reference carrier. The Satellite Router sends acquisition bursts at -20 dBm when
trying to acquire on a carrier that matches the reference carrier. When acquiring on a carrier
with a different configuration, the Satellite Router automatically adjusts the transmit power
of the acquisition burst such that it is received by the hub at the correct C/N .
0

Figure 54. Initial Power in Probe and iBuilder

17.1.2 Maximum Power

For each remote site, there is an absolute upper power limit imposed by the limitations of the
RF amplifier or BUC. For each BUC, there is also an upper limit of usable power imposed by
the linearity characteristics of the amplifier itself, in conjunction with the minimum spectral
purity requirements for the output signal.
Setting the maximum power in iBuilder has two purposes: to ensure that the remote site BUC
is not driven so far into the non-linear region that unacceptable levels of spectral regrowth
occur; and to establish a reference point for the Uplink Control Process to determine the
usable power headroom available at the remote site at any given time.
The data needed to set maximum power on the iBuilder Remote Information tab was obtained
during the procedure executed in "Determining the 1 dB Compression Point" on page 87. The
procedure in "Optional Procedure to Determine PN Max Power" on page 88 may provide a
more accurate maximum power during network operation. If that procedure was also
performed, the resulting value is added to iBuilder as a remote-side custom key.
100 iDirect Satellite Router Installation and Commissioning Guide
iDX Release 3.3