System Installation And Setup; Interference Prevention; Radio Frequency (Rf) Interference - HME Wireless 6000 Installation Instructions Manual

SECTION 2. SYSTEM INSTALLATION AND SETUP
2.1

INTERFERENCE PREVENTION

CAUTION: Interference may occur if the audio system is not properly installed.
The following types of interference could occur if precautions are not taken in installation of
the system. Read this section carefully before proceeding with the installation.
2.1.1

Radio Frequency (RF) Interference

Resolving the cause of RF interference is difficult and time-consuming. The following
precautions will help avoid the most common RF interference problems.
•
Find the best base station/antenna location before mounting it permanently.
•
Solder all joints (including crimp joints) at the speaker location. This is especially
important in damp climates
•
Be certain all joints and connections are tight.
•
Avoid leaving long lengths of unshielded wire anywhere in the audio system.
•
Ground the shield of the outgoing speaker cable. In severe cases of interference,
grounding the shield at the speaker may help.
AM broadcast and FM radio frequency interference may cause similar problems but require
different corrective action. AM interference symptoms may appear to be less severe at
certain times of day, since a 50% reduction of transmitter output power at dusk (5-7 PM) is
required in some areas for AM radio stations rated at or above 100kW. Note the following
symptoms carefully to determine the possible cause of interference. Call HME at
1-800-848-4468 if assistance is required.
AM Interference:
Static or hum may be heard in the headset when the system is active. The point of entry of
the AM interference is at the outside speaker/microphone via the cables connected to the
base station. In order to block out the AM signal, first locate and identify any AM station in
the area, and find out its operating frequency and transmitter output power. The system can
then be modified with a network of inductors and capacitors that will trap the undesirable
AM signal at the point of entry into the system. Static, hum and/or voice may be heard in the
headset when the system is active or when transmitting in either channel A or B. The point
of entry for the interference can be at three different locations: the outside speaker cables,
the COMMUNICATOR
may completely suppress or overpower the audio system's transmitter signal, depending on
the operating frequency, transmitter tower location and output power of the AM radio station.
It may be necessary to move the base station.
FM Interference:
A common symptom of FM interference is the presence of cracks, pops and other noises in
the Communicator when transmitting on either channel A or B, or when the system is active.
2400MHz Wireless Telephone Interference:
If there is a 2400MHz cordless telephone nearby, interference may occur. However, because
the Wireless 6000 is a frequency-hopping system, this problem is unlikely. If it does occur,
changing frequencies on the telephone may alleviate the problem. If not, move the phone as
far as practical from the base station, or ask the customer to use another type phone.
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receiver, and the base station transmitter. The AM station frequency
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