Lectrosonics R400a - Manual (Page 16)

R400A
LECTROSONICS, INC. 16
Frequency Coordination
Intermodulation interference is a problem constantly
lurking in the background, especially when working
in environments where simultaneous productions are
taking place in close proximity. In these cases, proper
frequency coordination is a must. There are basically
three methods to coordinate frequencies:
• Use the built-in frequency groups
• Scan for clear channels (See SmartTune
™
and Scan Function.)
• Call Lectrosonics
Frequency Compatibility Chart
Considering that multiple systems can be used in a produc-
tion, coordinating frequencies to minimize interference
between these channels can be a daunting process.
The Frequency Compatibility Chart was designed to as-
sist in minimizing intermodulation problems for multiple
channel wireless systems. It does this by identifying
potential intermodulation problems and listing compat-
ible frequencies and frequency groups. This chart can be
used with all Digital Hybrid Wireless ® (400 Series) receiv-
ers.
The chart divides the frequency blocks used in the North
American market into Set 1 and Set 2, then further di-
vides each row into two groups of eight frequencies each.
These frequency groups are labeled A and B and C and
D, and correspond to the factory set frequency groups
(Groups A, B, C and D) described in the Tuning Setup
Screen.
Understanding and using the Frequency Compatibility
Chart is not as difficult as it first appears. There is a pat-
tern of compatible frequencies that becomes apparent, as
illustrated on the Frequency Compatibility Diagram on the
next page.
The following guidelines should be observed when
selecting compatible frequencies:
1. Set 1 and Set 2 are NOT compatible.
Proper coordination requires that all frequencies be
taken from either Set 1 or Set 2, but not a combina-
tion of the two.
(The remaining guidelines make the assumption
that you are choosing frequencies within one
frequency set.)
2. Frequencies within an individual frequency
block in the same Set are compatible.
(Example: All 16 frequencies in Block 25,
Group A and B)
3. Frequencies from adjacent blocks, but different
Groups are compatible.
(Example: Block 21, Group C frequencies
are compatible with Block 22, Group D frequencies)
4. Frequencies from adjacent blocks and the same
Group are NOT compatible.
(Example: Block 26, Group B frequencies
are NOT compatible with Block 27, Group B
frequencies)
It is highly recommended that you choose frequencies
that are in the same set and same group.
By following these guidelines, it is possible to locate a
number of operating frequencies early in the production
that are free from intermodulation, then refine the list
during system setup.