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INTELIX
BALUNS HELP SPEAK BAT
Middleton, WI—Installing and maintaining audio systems outdoors
often presents unique challenges, especially when the goal
is to transmit high-frequency bat calls long distances without
sacrificing signal integrity. Mike Balistreri, owner of Avian
Consulting Services (ACS), was recently faced with that exact
challenge.
“The need to mount bat detectors on towers at heights in
excess of 50 meters is one of the common technical problems
that must be overcome while designing and implementing pre-
and post-construction wind site monitoring plans,” explains
Mr. Balistreri. “Difficulties and expense of erecting the
support towers aside, the bat researcher is faced with the
dilemma of gaining access to the recorded data. Common solutions
to this problem have included the use of telescoping towers,
microphone extension cables, and FM or other wireless transmission
devices. Unfortunately, all of these methods have inherent
physical or electronic deficiencies and limitations.”
 To
overcome the problems inherent in other systems, ACS installed
two Intelix AVO-A2MINI-WP-F
baluns on each audio cable run. The AVO-A2MINI-WP-F transmits
two channels of analog audio over standard twisted pair cabling,
such as Cat 5 or Cat 6. In the case of ACS’s application,
an exterior-grade, UV resistant cable was used.
“As a further advantage, these baluns are self-powered and
do not require an internal or external power source,” elaborates
Mr. Balistreri.
Designed for transmitting audio and video signals extended
distances, baluns balance unbalanced AV signals thereby making
the necessary impedance adjustment for sending signals over
different wiring systems. In addition, Intelix baluns feature
extremely high quality isolation transformers and common mode
chokes to ensure full hi-fidelity audio performance and eliminate
ground loop interference.
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| The Intelix balun system in use.
The device on top of the enclosure is a homemade light
sensor. |
“Many bat detector-recorder systems commonly suffer from
ground loop interference,” explains Mr. Balistreri. “This
occurs when a detector, which typically runs off of 12 volts,
is connected to the same power supply as the recorder, which
may run off of four or five volts via a voltage reduction
circuitry. This difference in potentials produces an unwanted
current that shows up as a low-level background noise on the
recordings. This interference can be compensated to some degree
by decreasing the input gain on the recorder. However, in
doing this, the system becomes less sensitive to the weaker
bat calls. The baluns effectively break the ground loop by
electronically isolating the detector and recorder, making
clean, non-interfered recordings possible.”
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| SonoBat screenshot number 1 of an
ultrasonic signal recorded through a 91 meter Cat 5 cable
using the balun system (left), and through a sole 0.4
meter patch cable (right). click
to enlarge |
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| SonoBat screenshot number 2 of an
ultrasonic signal recorded through a 91 meter Cat 5 cable
using the balun system (left), and through a sole 0.4
meter patch cable (right). click
to enlarge |
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| SonoBat screenshot number
3 of an ultrasonic signal recorded through a 91 meter
Cat 5 cable using the balun system (left), and through
a sole 0.4 meter patch cable (right). click
to enlarge |
Mr. Balistreri relied on Full Compass Systems, a leading
audio-visual distributor, for preliminary design assistance
and for purchasing the Intelix equipment. “The folks at Intelix
and Full Compass have been very helpful and are eager to explore
unique applications of their products.”
About Avian Consulting Services.
Founded by Mike Balistreri, Avian Consulting
Services (ACS) provides top-level environmental consulting
services to the wind energy industry, including pre- and post-construction
plant and wildlife surveys. ACS can be contacted online at
www.acswind.com,
or by phone at 505-235-8425.
About Full Compass Systems.
Founded in 1977, Full Compass is a national leader in professional
audio, professional video, AV, and lighting sales and rentals.
Full Compass can be contacted online at www.fullcompass.com,
or by phone at 800-356-5844.
About Intelix.
Intelix offers the broadest line of baluns in the professional
AV marketplace, including solutions for multiple formats of
audio and video, VGA, DVI, HDMI, USB, and PS2. In addition
to baluns, Intelix manufactures an extensive line of serial
controlled mic/line, matrix, room-combine, and automatic mixers.
Complete product information is available online at www.intelix.com,
or by phone at 866-4-MATMIX.
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