Frequency Concerns - Sennheiser EK 100 G3 Manual

Frequency Concerns

The successful operation of an RF wireless system depends greatly on two things:
1) The frequencies to be used must be free of inteference from other signals in the air. Frequency agile
wireless systems (those offering a high number of user-selectable operating frequencies) provide the
most effective means of avoiding such interference.
2) The frequencies to be used must be calculated exactly to avoid interfering with each other. Not
only do these frequencies need to be spaced apart far enough, they must also be carefully calculated
to avoid creating harmonics which can cause other frequencies to have problems such as dropouts
and static "hits." These undesirable effects are known as "intermodulation." G3 makes this simple by
offering preset frequencies called "CHANNELS" which reside in a frequency "BANK." When operating
multiple systems in the same frequency range (i.e. range "A" 518-558 MHz), you should always run
these systems in the same BANK.
Although evolution wireless G3 is one of most frequency agile products on the market, care must be
taken in selecting your systems' operating range and frequencies to insure that interference-free opera-
tion is achieved.
location
Geographic location plays a major role in the effective performance of your wireless microphone and/or
monitoring system. The primary source of airwave competition is from television broadcast transmis-
sion towers. It is very likely that most locations where a wireless system is to be used will be within the
effective transmission range of at least one, if not more, of these television broadcasting stations. In
planning your systems' frequency requirements, one should determine what frequencies are in use by
local television stations.
Local television stations are not the only transmissions that may cause interference. Nearby wirelesss
communication devices and other wireless microphone systems may also introduce obstacles when
planning an effective wireless system. Having a complete knowledge of your RF environment (the pos-
sible sources of RF interference including their frequencies), as well as a functional frequency coordina-
tion scheme (using the BANK system) are very important when planning a wireless microphone system.
Sennheiser's website ( HYPERLINK "http://www.sennheiserusa.com" www.sennheiserusa.com) has an
interactive frequency finder which can assist you in finding which local TV stations are broadcasting in
your area.
Effective frequency coordination is a means of scientifically determining the compatibility of multiple
RF systems operating simultaneously. It is recommended that you follow our frequency coordination
schemes when planning a multi-channel wireless system within your RF environment.
dTv (digital Television
Now that the FCC has mandated that all television broadcasts are digital, it is more important than ever
to ensure you are on a clear frequency. Additionally, portions of the UHF spectrum are now reallocated
by auction and/or emergency operation. As of June 12th, 2010, the FCC has made it illegal to operate
wireless devices in the 698-806 MHz range.
It's important to remember when incorporating evolution wireless G3 into a wireless system, that each
evolution wireless G3 system is manufactured to operate within a particular frequency range (A, B, G
etc.) Each range is broken down into 1,680 user-selectable frequencies.
Remember, we always want to run multiple systems in the same range (e.g. A, B, G) in the same BANK.
You would use the same BANK but different channels under that bank. The number of preset chan-
nels per BANK depends on what series of evolution G3 you have. For example, the "LE" series has up
to 6 channels per BANK while the 500 series has up to 32 channels per BANK. The following evolution
wireless G3 frequency combination charts which also may aid in determining frequency compatibility if
you are using evolution wireless G3 with wireless products made by other manufacturers. When using
multiple evolution wireless G3 systems, it is important to make certain that all channels in your system
follow this compatibility scheme to guarantee that your system will operate interference free.
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