Channel Selection

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 receivers, press and hold seek for 5 seconds. Repeat the process to unlock. 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 (lettered channels at 72 MHz and channels that start with a “2” for 216 MHz). Listen to the audio through the headphone or via the 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 transmitters in the same space, the most number of channels that will work simultaneously is six at 72 MHz and three at 216 MHz. With all of the transmitters off, listen for interference on all the wide band channels via the headphone jack. Using the frequency compatibility tables on pages 47-48, 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. If there is no interference the following channels are recommended: A, C, E, I, J, and H for 72 MHz and channels 2A, 2K and 2V at 216 MHz.

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 compatibility tables on pages 47-48) in this case as long as the adjacent channel transmitter is at least 50% further away from the receiver as its transmitter. Example: The transmitter for the receiver on channel E is 100 feet from the receiver. The adjacent channel transmitter on channel D should be at least 150 feet away.

Notes in regard to using 72 MHz and 216 MHz systems:

i.72 MHz in a secondary frequency band. This means that other transmitters are licensed to use these frequencies. Thus, you may experience interference from paging transmitters and other type transmissions. You will need to find a clear channel by listening to all the wide band channels.

ii.216 MHz is a primary frequency band and no other types of transmissions are authorized to use it. Thus, you will find the highest probability of clear channels in this band. However, you may experience intermodulation of the TV Channel 13 aural carrier if there is a channel 13 transmitter in your area and you are close to the transmitter. If you cannot find a clear channel in 216 MHz band due to channel 13, it is recommended that you switch to a 72 MHz system.

NOTE: The LR-300-072 can only be used with the 17 wide band 72 MHz channels, if you are using the LR-300 choose only lettered wide band frequencies on your transmitter.

Information

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Listen Technologies LR-500, LR-400, LR-300 manual Channel Selection
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LR-500, LR-300, LR-400 specifications

Listen Technologies has established itself as a leader in providing innovative audio solutions that enhance communication in various environments. Among their standout products are the LR-400, LR-300, and LR-500, which are designed for assistive listening, language interpretation, and audio distribution. Each of these portable receivers offers unique features, ensuring that users have a seamless experience during presentations, events, and meetings.

The LR-400 is a versatile listening receiver that operates on a wide frequency range. It is specifically engineered for maximum clarity and disturbance-free reception. One of its primary features is the ability to connect directly to a variety of audio sources, making it compatible with numerous sound systems. This device boasts a prominent LCD display, which provides real-time information about channel selection and battery life, enhancing user accessibility. Additionally, the LR-400 supports both mono and stereo audio configurations, catering to different listening preferences and needs.

The LR-300, on the other hand, is specifically built for personal listening purposes, often utilized in classrooms, theaters, and guided tours. It is lightweight and compact, designed for ease of use and portability. One of the LR-300’s standout features is its long battery life, allowing for extended use without the need for frequent recharging. Users can easily adjust the volume for optimal sound levels, ensuring they can fully engage with the presented audio without compromising comfort. The LR-300 can also be equipped with various headphones and earphones, providing flexibility to suit individual preferences.

Finally, the LR-500 expands on the capabilities of its predecessors with advanced technology aimed at improving audiology experiences. It offers a digital communication protocol that significantly enhances audio quality while minimizing interference. The LR-500 is particularly suitable for professional settings, such as conferences and multinational events, where language interpretation is required. With multiple channel options, it allows participants to select their preferred language effortlessly. Its robust design ensures durability, making it suitable for frequent travel and usage in diverse environments.

In conclusion, the LR-400, LR-300, and LR-500 receivers from Listen Technologies exemplify the company's commitment to delivering high-quality audio solutions. Each device is equipped with advanced features and technologies that address specific user needs, whether for personal listening, language interpretation, or professional audio distribution. With their reliability and performance, these receivers enhance communication and accessibility in various settings, ensuring that every voice is heard loud and clear.
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