JRC NDR-91 - Troubleshooting: Interference and Intermodulation

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The
noise
goes
directly
to the receiver
The
noise
goes
to the antenna
By removing
the antenna,
connecting
the receiver to
other
antenna, using the
other
power
supply line
and moving
the installation
place,
the
route can be found.
(3)
Countermeasure
Basically,
the countermeasure must
be
taken
at the noise
source
side.
In
any
cases,
all
equipments
must be
grounded.
If
the equipment is
surely
grounded
by
means of
the
wide copper board, the noise interference may
be
resolved. Also, a
line filter which
suppresses
the HF noise is very effective
at
the
power
supply
wire. After
finding
the
noise
source and noise
route,
please
examine
the trouble and ask the countermeasure to
the maker
or sales agent of that
equipment
which is of the noise
source.
O
6.3.4
Interference
by
the transmitter of
your
station
At the station where
many radio equipments are installed,
when some
transmitter
transmits the radio
wave,
the
receiver
may catch the noise in
spite
of
that the frequency
is
different.
It
is a
rule
that
the receiver is muted
by
using
-BK
signal
while transmitting.
But when
performing
the
simultaneous
transmission and reception
because
of the duplex
communication,
it
is important to
separate
transmitting
antenna
and
receiving
antenna as
far
as
possible.
Even
though
the antennas
are
located
at same
distance
from
the
transmitting
antenna, the receiving antenna
located
not in
parallel
to the
transmitting
antenna
has less
interference.
Generally,
the interference
depends on the
difference between the
receiving
frequency
and transmitting
frequency. The
bigger the difference
is,
the less the interference is.
Also,
the degree of the
interference
depends on the
performance
of
the
antenna
multi-coupler,
protective
diode,
etc.
Noise
source
The
noise
goes
to the
via
the
power
cable.
.,.\
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