Bird Technologies 5012 User Manual

INSTRUCTION SHEET

WIDEBAND POWER SENSOR

MODEL 5012

©Copyright 2008 by Bird Electronic Corporation

Instruction Book P/N 920-5012 Rev. C

Description

The Bird 5012 Wideband Power Sensor (WPS) is a Thruline sensor
that can measure average, peak, or burst power, VSWR, crest factor,
and Complementary Cumulative Distribution Function (CCDF). It
can be used with the Bird 5000-EX Digital Power Meter (DPM) and
the Bird Virtual Power Meter Software (VPM).

 NOTE: Firmware upgrades extending the WPS’s capabilities may

be periodically released. For the latest firmware upgrade, contact
Bird Customer Service at [phone] or visit our website at

http://www.bird-electronic.com

Connections

WARNING

Never attempt to connect or disconnect RF equipment from the

transmission line while RF power is being applied.

Leaking RF energy is a potential health hazard.

To connect the WPS to the Digital Power Meter, use the serial cable
provided. Connect the male end of the cable to the DPM and the
female end to the WPS. A separate power supply for the WPS is not
required when using a DPM.

There are two ways to connect the WPS to a PC running the Virtual
Power Meter Software:

y To connect using the serial port, first connect a 12V DC power

supply to the WPS. Once the STATUS LED turns on and begins
blinking, use the serial cable provided and connect the female end
of the cable to the computer and the male end to the WPS. The
WPS must be powered up before connecting to the PC.

y To connect using the USB port, connect the USB cable to the

computer and to the WPS. A separate power supply is not required
when using the USB port.

 NOTE: When using the optional serial to USB adapter, connect

the WPS serial port to the adapter’s serial port, and the adapter’s
USB connector to the PC.

Zeroing Sensor

Average Power

Peak Envelope Power

0 W

50 W

100 W

Over time, the sensor’s “zero value” (reading with no applied RF
power) can drift, making all readings inaccurate by this value. For
example, if the zero value is –0.02 W, measuring a 50 W signal will
give a reading of 49.98 W, a 0.04% error. Measuring a 1 W signal will
give a reading of 0.98 W, a 2% error. If the drift would be a significant
error, rezero the sensor:

y Make sure the sensor has reached a stable operating temperature.

y Make sure no RF power is applied to the sensor.

y Press “Zero”. Calibration will begin.

y Calibration will take about 30 seconds. Do not interrupt the

calibration! A bar on the screen will display calibration progress.

y After successful calibration, “Cal Pass” or “Calibration Complete”

will be displayed. Press any key to return to normal operation.

y If calibration fails, “Cal Fail” will be displayed. Press a key to

return to normal operation, then check that the WPS is properly
connected, and that the RF is off. Rezero.

Function Descriptions

Figure 1

Average and Peak

Envelope Power

Square Wave Signal

Average Power

Average power is a measure of the equivalent “heating” power of a
signal, as measured with a calorimeter. It measures the total RF
power in the system, and does not depend on number of carriers or
modulation scheme. The WPS is a broadband sensor that measures
power across its entire frequency range. Its diodes operate in their
‘square law’ region so that the detector output is directly proportional
to the average power, without any additional error correction.

Average power is the most important measurement of any
transmission system since the average power is normally specified on
the operating license. It is also valuable as a maintenance tool,
showing overall system health, and for calibration.

VSWR

Rho (µ) = PRP

F

⁄

Filter

Too Small

Filter

Too Wide

Correct

Filter

Noise

Signal

VSWR measures the relation between forward and reflected average
power. The Bird Wideband Power Sensor calculates the VSWR from
the Forward and Reflected Average Power measurements. Rho and
Return Loss are also the same measurement, but in different units:

, , and

The health of the feedline and antenna systems can be monitored
using VSWR measurement under full power operating conditions.
High VSWR is an indicator of feed line damage, overtightened cable or
feed line clamps, or antenna changes/damage due to weather
conditions, icing, or structural damage to the tower.

Video Filter

Figure 2

Video Filter Settings,

300 kHz Signal

Except for average power and VSWR measurements, all WPS
measurements rely on a variable video filter to improve accuracy. This
filter can be set to either 4.5 kHz, 400 kHz, or full bandwidth. It should
be as narrow as possible while still being larger than the demodulated
signal bandwidth (video bandwidth). Narrowing the filter limits the
noise contribution caused by interfering signals. Listed below are some
common modulation schemes and the appropriate video filter.

Video Filter Modulation Type

4.5 kHz CW Burst (Burst width > 150 µs), Voice Band AM,

400 kHz CW Burst (b.w. > 3 µs), GSM, 50 kHz AM, DQPSK

Full
Bandwidth

FM, Phase Modulation, Tetra

CW Burst (b.w. > 200 ns), CDMA, WCDMA,
DQPSK, DAB/DVB-T