LISTEN TECHNOLOGIES CORPORATION +1.801.233.8992 1.800.330.0891 Fax: +1.801.233.8995
Internet: www.ListenTech.com All specifications subject to change without notice.
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The antenna for the LT-800 or the LR-100 can be mounted directly on the unit if desired. However, you may find that the unit will
provide better performance when the antenna is located elsewhere. If you plan to mount the antenna in a different location than
on the top of the unit, you must use cable and connectors rated at 50 ohms. Although cable used for cable TV installations looks
similar to this cable, it won’t work with your Listen system.
If you need to run cable over a greater length than 50 feet for 216MHz applications or greater than 100 feet for 72MHz applica-
tions, we recommend that you use RG-8 cable rather than RG-58. It is a lower loss cable, meaning that more of your signal will
reach the antenna.
Long cable runs can result in signal degradation due to “loss” characteristics of the cable. At 72MHz, there is a loss of 2dB per
100 feet of cable and at 216MHz, there is a loss of 5 dB per 100 feet of cable. (A 3dB loss means half of your power has been
lost.) However, it is better to suffer coaxial power loss than to try to shoot your signal through obstacles! Obstacles,
especially metal, can create drop-outs or reflections of your signal that will result in poor listening conditions.
For proper and dependable operation, Listen receivers should receive a strong and consistent signal from the originating transmit-
ter. The following strategies should be used maximize this signal:
a. When designing and installing your system, keep in mind that the location of
both the transmitting and receiving antennas
is critical to maximizing signal strength.
b. Eliminate or minimize obstructions between the transmitting antenna and the receiving antenna.
c. Minimize the distance between the transmitting and receiving antennas.
d. Move transmitting and receiving antennas away from metal objects.
e. For the LR-100, consider using a remote antenna instead of the supplied 90-degree helical antenna. This will allow you to
place the antenna at a location with improved line of site to the transmitting antenna. (You will need to be careful about the
type and length of coaxial cable; see the note below.)
f. Place the transmitting antenna as high as possible.
g. Orient both transmitting and receiving antennas vertically.
h. For 216MHz unit only, consider using a gain antenna such as a Yagi type antenna.
CAUTION: When installing antennas, ensure the antenna is clear of power lines.
NOTES: If the RF signal to the 216MHz models is too high, the audio will be distorted. This may happen if you are within 40 feet
of the LT-800-216 transmitter. Consider reducing the output power of the transmitter or optionally removing the antenna on the
LR-100 (there is sufficient internal antenna inside the LR-100 to receive an adequate signal from the transmitter).
Coaxial cable, connectors, and optional antenna mounting kits are available from Listen. Visit our website or ask your dealer for
details.
Appendix B
Strategies For Maximizing RF Reception With Listen Products
Appendix C
A Note on Coaxial Cable
Appendix B, Appendix C
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