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INSTALLATION CAUTIONS
Extension Antenna cables — For best results, use high quality coaxial cable with a 50
Ohm impedance. Specifications will vary by cable manufacturer. For best results, use
cable with minimal attenuation. The longer your cable, the more you will reduce the 100-
meter range between transmitter and receiver antenna. A well-placed pair of extension
antennas will eliminate trouble spots and generally improve overall performance of the
wireless.
C
OMMON
S
OURCES
OF
RF I
NTERFERENCE
The typical sources of interference for conventional wireless mics can be high-powered
broadcasters such as radio stations and TV transmitters, or other short-range wireless
devices, including multiple radio microphones operating at the same location (either by
design, or by coincidence), that operate in proximate (or harmonically related) bands.
Less commonly, interference may arise from spurious outputs emitted by electronic equip-
ment (notably computers, printers, or similar devices with digital clocks), faulty electrical
equipment, neon signs, dimmers and lighting controllers, and so forth.
Many UHF and VHF mics are especially vulnerable because they share the RF spectrum
with the very high-powered transmitters for television. The coming conversion to digital
and high-definition broadcast will increase the problems for UHF and VHF.
The 2.4 to 2.4835 GHz frequency band is not only well above the fundamental (nominal)
transmission frequencies of such strong analog and digital broadcasts, but also high enough
to escape interference problems occurring at the strong first harmonic of even the highest
digital television broadcast. The band is approved worldwide for a variety of uses, includ-
ing such diverse transmitters as baby monitors, garage door openers, wireless LANs,
amateur satellite, cordless telephones, etc. Compared to RF broadcast sources like tele-
vision and radio stations, these low power devices produce very localized, short range
interference; furthermore, many of the devices working in the 2.4 GHz range use spread
spectrum transmission and reception. Both of these facts mean such uses of the RF
spectrum are less likely to cause interference with, or suffer from interference from the
use of, Sabine’s systems.
Your first step in checking for interference should be utilizing the Scan function in the
SWM7000 Remote Control Software. RF scanning will reveal potential RF sources in your
location and allow you to make an informed choice of channels to use. The scanner can
scan for long periods of time and will give you a report of RF activity over time for each of
the 70 channels available on your Smart Spectrum system. See Section 13.4.2.5 RF
Scan of the SWM7000 Operating Guide for more details on RF scanning.