Making a Transmission

Select the channel you want to transmit on, then press and hold the Push to Talk button. Release the Push to Talk button when you’re finished talking to let the other party respond.

xx To prevent stuck microphone problems or situations where the Push to Talk button is pushed accidentally, the radio limits your talk time to 5 minutes in a single transmission.

xx For the best sound quality, hold the microphone about two inches away from your mouth.

xx See the channel lists starting on page E-23 for a list of receive-only channels.

Changing the transmission level

In most situations, 1 W transmission power is all you need. If you find yourself far away from other stations and have trouble getting a response, you may need to increase the transmission power. If your radio is powered by a Li-Ion battery, you can press and hold the BOOST button to transmit at 6 W. Alkaline battery power boost is limited to 2.5 W.

To increase the transmission power in increments:

1.Select the channel you want to transmit on.

2.Press ENTER-H/M/Lto switch to the next transmission power level (for example, from 1 W to 2.5 W, from 2.5 W to 6 W, or from 6 W back to 1 W).

3.The display shows the new transmission power as 6 W, MID, or LOW. The transmit power remains at the new setting until you change it again.

## Note: Don’t forget to change the transmission setting back to 1 W when you move close to other stations.

Some channels (for example, channels 13 and 67) limit the transmission power to 1 W. When you tune to a limited-power channel, the radio automatically switches to 1 W. See the channel lists starting on page E-31 for a list of power-restricted channels.

Digital Selective Calling Features

What is DSC?

Digital Selective Calling (DSC) is a standard that allows you to call other stations using their unique identification code (the Maritime Mobile Service Identity or MMSI number), just like you would call a phone number. To call another station, just enter that station’s MMSI number and choose the voice channel you want to talk on. The radio uses channel 70 to transmit your MMSI number to the other station along with the voice channel you requested. If the other station accepts your call, both radios automatically switch to the requested voice channel so you can talk to the other station.

DSC provides a system for automated distress calls. At the touch of a button, the radio can transmit your MMSI number, the nature of your distress, and your current position based on data from your GPS receiver. The radio repeats the distress call every few minutes until it receives an acknowledgement.

The DSC standard dedicates a VHF channel—channel 70—to digital transmissions only. Since digital transmissions require less bandwidth voice transmissions, channel 70

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Uniden MHS135DSC Radio Owner’s Manual

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Uniden MHS135DSC Digital Selective Calling Features, What is DSC?, Making a Transmission, Changing the transmission level
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MHS135DSC specifications

The Uniden MHS135DSC is a highly regarded handheld marine radio designed for boating enthusiasts and professionals alike. This device combines advanced technology with user-friendly features, making it an essential tool for effective communication on the water.

One of the standout features of the MHS135DSC is its Digital Selective Calling (DSC) capability, which enhances safety by allowing boaters to send automated distress signals. This feature significantly improves the speed of communication in emergencies, sending distress alerts that include the boat's GPS location to nearby vessels and coast guard stations. The MHS135DSC also supports Class D DSC, which means it can prioritize emergency calls over regular communication.

The radio is built to withstand the rigors of marine environments, featuring an IPX8 waterproof rating, making it submersible in water up to 1.5 meters for 30 minutes. This robust design ensures that the radio remains operational even in adverse weather conditions, providing peace of mind to users.

Another notable characteristic of the MHS135DSC is its built-in GPS receiver. This feature allows users to easily access their location and navigate more effectively. The unit can display real-time coordinates, and it integrates seamlessly with other marine navigation systems. The internal GPS also facilitates DSC operations, ensuring that crucial location data is sent during distress calls.

The MHS135DSC operates on both the VHF marine radio band and supports a wide range of channels for effective communication. With 1W/5W power settings, users can adjust transmission strength according to their communication needs, whether they are in close proximity to other vessels or need to reach distant stations.

A user-friendly interface is an additional asset of this radio. The clearly labeled buttons and intuitive design make it easy to operate, even for those new to marine electronics. The radio also features a bright LCD display for clear visibility even under direct sunlight.

Battery life is another critical aspect, and the MHS135DSC excels in this area with a rechargeable lithium-ion battery that provides long-lasting power. The device also supports battery save modes, ensuring that the radio remains functional during extended outings.

In summary, the Uniden MHS135DSC is a feature-rich handheld marine radio that prioritizes safety, usability, and durability. With its DSC capabilities, waterproof design, built-in GPS, and robust battery life, it serves as an essential communication tool for anyone navigating the waters, ensuring connectivity and peace of mind.
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