User's Manual

March 1, 2002 Page E15
Upstream Power
The output level of the Cable Modem establishes the subscriber transmitter’s output power. An
automatic feedback loop, controlled by the WMTS, commands each CM to adjust its output level
such that the level of the signal received at the head end is suitable for demodulation by the WMTS.
The user may tune this power control loop by modifying the
UpstreamRxGain parameter in the
RegTree file. (See Vyyo V3000 Wireless Hub User’s Manual section 7.2). Setting this parameter to 0
will generally yield satisfactory performance.
The ARCi subscriber ODU is factory calibrated to maximum FCC permissible EIRP when the DOCSIS
cable modem is at its maximum power output level.
The most accurate method of setting the actual output power level is to attach an RF power meter
capable of measuring up to 6 GHz to the output of the hub transmitter through a 15 inch long
RG142B/U SMA-SMA cable and then adjusting the IF level until the power indicated on the meter is +15
dBm. However, ARCi does not recommend that this adjustment be made in the field unless under the
direct instruction of the ARCi factory.
Warning! The transmitter must never be operated without a 50 Ω load attached to its
RF output connector. Be sure to remove the DC power from the transmitter prior to
removing the load from the output.
IMPORTANT NOTE: To comply with FCC RF exposure compliance
requirements, antenna installation and device operating configuration
described in this user manual must be satisfied. The antenna(s) used for
this device must be fixed-mounted on outdoor permanent structures with
a separation of at least 1.5 meters from all persons during normal
operation.