10
Chapter 5
Maintenance
RF Assembly Resistance Test
Note:
These
tests
are
by
no
means
a
necessity
to
the
operation
of
the
attenuator
but
merely
guidelines
for
the
users
information.
Accurate
measurement
of
the
DC
resistance
between
the
input
to
ground,
output
to
ground,
and
input
to
output
will
provide
a
good
check
of
the
condition
of
the
attenuator.
Checking
the
DC
resistance
is
simply
used
to
measure
a
change
in
the
resistance
over
time.
Tracking
the
DC
resistance
should
start
before
the
unit
is
first
put
into
service.
Perform
the
following
steps
and
record
the
value
for
future
comparison.
Resistance
measurements
should
be
taken
periodically
according
to
use.
Preparation:
Tools:
Common
hand
tools.
Ohmmeter
with
an
accuracy
of
±
1%
at
50
ohms
(or
use
a
resistance
bridge).
Use
low
resistance
leads,
preferably
a
short
piece
of
50
ohm
coaxial
cable
fitted
with
an
appropriate
connector
or
alligator
clips.
Temperature
of
the
attenuator
should
be
stabilized
between
20°C
to
25°C
(68°F
to
77°F).
DC Resistance Measurement
Note:
It
is
recommended
that
this
resistance
check
be
performed
each
time
the
attenuator
is
to
be
used.
1.
Turn
off
RF
power
before
making
any
disconnections.
2.
Disconnect
the
RF
coaxial
line.
3.
Take
the
following
measurements:
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.
