Interference
1.
Background magnetic field signals or interference may be present in
any location and may not be anything to do with the loop system.
Monitor this with a loop receiver (such as an ILR3). If the interference
is still present with the loop system switched off, then you need to
locate and eliminate the source of interference before switching the
loop system back on.
2.
AC power hum can be introduced into the system if signal cables are
grounded at multiple points. This can cause earth currents to flow
around the screen wires of signal cables and introduce unwanted noise
into the audio path.
3.
Magnetic fields can be induced into any low impedance electrical path
or loop. Multiple ground earth systems may experience the pick up of
the loop signal, and cause difficulties with other systems that are not
designed to reject such interference. Check entire sound system for
evidence of loop signal, and trace source of pick-up.
4.
Under certain circumstances, the loop signal may appear as jagged
lines or hum bars on a CCTV picture. This could be due to running
CCTV (low impedance unbalanced 2-wire circuit) cables in close
proximity to the loop cable. Separate the cables to reduce the effect.
5.
Remote (and apparently unconnected) PA systems can sometimes
pick up loop signals. This is usually because the loop cable becomes
damaged (see point 1 of Instability) or induces signals into the remote
system through long unbalanced cables. Always run long audio signal
cables as 3-wire balanced circuits & keep away from loop cables.
6.
See also point 1 of Instability.
ACCESSORIES
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