Listen Technologies LT-700-150 - Manual (Page 17)

13
Channel Selection
It is important to choose channels that are free from interference to achieve proper operation of your
Listen equipment. This process is trial and error. Before turning on the transmitter, listen to the wide
band channels. Listen to the audio through the headphone or on a Listen receiver or
receiver / speaker. Choose a channel with the least amount of interface. Unless you are interfacing
with an existing narrowband transmission system, always use a wide band channel. If you are using
multiple channels follow this process:
a. Same Space If you are using multiple transmitters in the same space, the maximum number of
channels that will work simultaneously is six at 150 MHz. With all of the transmitters off, listen for
interference on all the wide band channels via the headphone jack on a Listen receiver. Using
the frequency chart on page 16, eliminate any channels that have noticeable interference. Now
choose the channels with the widest channel spacing. It is recommended that adjacent channels
be spaced at least 300 kHz.
b. Distributed spacing if you are using transmitters that are spread out over space, you can achieve
more simultaneous broadcast channels. However, it is critical that your receiver(s) be located as
close to its transmitter as possible. You can use adjacent channels (see frequency chart on page
16) in this case as long as the adjacent channel transmitter is at least 50%
further away from the receiver as its transmitter.
It is highly recommended that after channel selection has been achieved, you lock the channel
so that it cannot be changed by the user. To accomplish LOCK on the LT-700, press both the UP or
DOWN buttons simultaneously for 5 seconds. Repeat the process to unlock.
Wide Band Recommendation
Listen recommends that you always use
a wide band channel unless you need to
be compatible with existing narrow band
receivers from other manufacturers. Wide
band channels have lower noise than their
narrow band counterparts.
At 150MHz
The LT-800 at 72MHz operates on 6 wide
band channels and 27 narrow band
channels.
• Numbers (0-6)= Wide Band Channels
(Example: 4)
• Numbers (7-32)= Narrow Band
Channels (Example: 32)