Bird Technologies Group 6138X Manual De Usuario

REQUIRED EQUIPMENT

The following equipment is required in order to per-
form the antenna isolation measurements.

1) Signal generator for the frequencies of interest

capable of a 0 dBm output level. Modulation is
not necessary.

2) Bird Technologies “Signal Hawk” spectrum ana-

lyzer which will cover the frequencies of interest
and is capable of observing signal levels down
to -100 dBm or better.

3) Double shielded coaxial test cables made from

RG142, RG55 or RG223 coaxial cable.

MEASUREMENT PROCEDURE

To measure the antenna isolation perform the fol-
lowing in a step-by-step fashion.

1) Set the signal generator for a 0 dBm output level

at the center frequency of the boosters pass-
band.

2) Set the spectrum analyzer for the same center

frequency and a sweep width equal to or just
slightly greater than the passband chosen ear-
lier in step 1.

3) Temporarily connect the test leads of the signal

generator and spectrum analyzer together
using a female barrel connector, see Figure 3.
Observe the signal on the analyzer and adjust
the input attenuator of the spectrum analyzer for
a signal level that just reaches the 0 dBm level
at the top of the graticule.

4) Referring to figure 3, connect the generator test

lead to one side of the antenna system and the
spectrum analyzer to the other then observe the
signal level. The difference between the
observed level and 0 dBm is the isolation
between the sections. If the signal is too weak
to observe, the spectrum analyzer’s bandwidth
may have to be narrowed and it’s input attenua-
tion reduced. The isolation value measured

Isolation (dB)

Figure 3: Typical test equipment interconnection for measuring antenna isolation.