Uniden MHS75 VHF Marine Radio Owner’s Manual
Making a Distress Call
For future reference, write your boat’s name & call sign here:
Speak slowly — clearly — calmly.
- Make sure your radio is on.
- Press the 16/9-Tri button to switch to Channel 16 (156.800 MHz). (If the corner of the display does not show 16, press the 16/9-Tri button again until it does.)
- Press the Push to talk button and say, “MAYDAY –MAYDAY– MAYDAY.”
- Say, “THIS IS {name or call sign of your boat}.”
- Say, “MAYDAY{name or call sign of your boat}.”
- Tell where you are (what navigational aids or land-marks are near, or give your position from a GPS).
- State the nature of your distress (e.g. sinking, medical emergency, man overboard, fire, adrift, etc.).
- Give the number of persons aboard and describe the condition of any injured persons.
- Estimate present seaworthiness of your ship (e.g. how immediate is the danger due to flooding or fire or proximity to shore).
- Briefly describe your ship (length, type, color, hull).
- Say, “I WILL BE LISTENING ON CHANNEL 16.”
- End message by saying, “THIS IS {name or call sign of your boat} OVER.”
- Release the Push to talk button and listen for a response. If you do not get an answer after 30 seconds, repeat your call, beginning at step 3, above.
Introduction
Features
The MHS75 provides the following key features:
- Submersible design Complies with JIS8/IPX8 water-resistant standards, which means the radio can be submerged in 1.5 meters of water for 30 minutes without damage.
- Memory scan mode Lets you save channels to memory and monitor them in quick succession.
- Transmitter power level select Lets you boost the transmitter power from 1 Watt to 2.5 or 5 Watts for added transmission distance.
- Battery level display and low battery alert.
- Dual, Triple and Quad Watch operation These different watch modes let you monitor up to two Coast Guard Distress/Hailing channels and one weather channel along with one regular marine channel.
- All marine VHF channels for the U.S., Canada, and international waters
- National Oceanic and Atmospheric Administration (NOAA) weather channel watch Sounds a warning tone when a hazard alert is issued.
Getting Started
What’s included
If any pieces are missing or damaged, contact Uniden Customer Service (see back cover for contact information). For information on available accessories, visit www.uniden.com.
Parts of the MHS75
Reading the display
The LCD display shows different information depending on what you are doing. This sample screen shows some of this information. The table below shows all the possible icons and what they mean.
Display icons and what they mean
How It Works
The MHS75 radio has three main operation modes: normal mode, scan mode, and weather mode.
In addition to the three operation modes, the MHS75 provides four different watch modes which you can activate during any operation mode. In the watch modes, the radio briefly checks for activity on a specific channel, then returns to its previous operation.
Note: Private boats must monitor channel 16 whenever they are underway. Water-going vessels should have either Triple Watch or Dual Watch on at all times.
Normal mode operation
- To transmit, remove the radio from the charger, then press and hold the Push to Talk button. Release the button when you are finished talking.
- For the best sound quality, hold the microphone about two inches from your mouth while you’re talking.
- Press the Channel Up button to move up one channel at a time. Press and hold the button to scroll quickly up the channels.
- Press the Channel Down button to move down one channel at a time. Press and hold the button to scroll quickly down the channels.
- To change the transmit power, press the 1/5W-2.5W button. The transmit power switches between 1 Watt and 5 Watts each time you press the 1/5W-2.5W button.
- To change the transmit power to 2.5 Watts, press and hold the 1/5W-2.5W button for 2 seconds. Press and hold the button again to change back to the previous transmit power (either 1 Watt or 5 Watts).
Normal mode with Weather Alert Watch
If you activate Weather Alert Watch while operating in normal mode, the radio checks the most recently used weather channel every seven seconds. If it detects a weather or other hazard alert, it will switch to that weather channel. (If you are actively transmitting, the radio waits until you finish your transmission before checking the weather channel.)
Normal mode with Triple Watch or Dual Watch
If you activate Triple Watch while operating in normal mode, the radio checks channels 16 and 9 every two seconds; with Dual Watch turned on, the radio only checks channel 16. The radio will not check channels 16 or 9 while you are actively transmitting; it waits until your transmission is finished and then checks the channels.
Normal mode with Quad Watch
You can activate Weather Alert Watch and Triple Watch at the same time to monitor four channels at once (Quad Watch). The radio performs the Triple Watch and Weather Alert Watch checks at their scheduled time:
Scan mode operation
You can save channels into memory and then use scan mode to monitor those channels from lowest to highest. If the radio detects a signal on a channel, it stays on that channel as long as the signal is received; when the signal stops, the radio continues scanning.
Using the radio in scan mode
- To activate scan mode, press Scan-Dual.
- You must have at least two channels in memory to start a scan.
- You cannot transmit while in scan mode.
- To save a channel into memory, select the channel, then press the Mem button. The Mem icon shows on the display whenever you tune to that channel.
- To remove a channel from memory, set the radio to that channel, then press the Mem button. The Mem icon no longer shows on the display.
- When the radio stays on a channel, press Channel Up to leave that channel and resume scanning.
- To end the scan, press the Scan-Dual button again; the radio remains on the last scanned channel.
Scan mode with Weather Alert Watch
If you activate Weather Alert Watch while in scan mode, the radio checks the most recently-used weather channel every seven seconds, then continues scanning the next channel in memory:
Scan mode with Triple Watch or Dual Watch
If you activate Triple Watch while operating in scan mode, the radio checks channels 16 and 9 every two seconds, then goes on to scan the next channel; with Dual Watch turned on, the radio only checks channel 16:
Both Weather Alert and Triple/Dual Watch in scan mode
You can activate Weather Alert Watch and Triple/Dual Watch at the same time. The radio performs both checks at their scheduled time:
Weather mode
The NOAA weather channels now cooperate with the FCC to alert you of other hazards besides weather (child abduction alerts, nuclear, biological, etc.). In weather mode, the radio monitors one of the ten NOAA weather channels. If any type of alert is received, the radio sounds an alert tone and the display blinks.
Using the radio in weather mode
- You cannot transmit while in weather mode.
- To enter weather mode, press the WX-Alert button.
- To turn off the radio’s alert tone, press any button.
- To cancel weather mode and return to the previous marine channel, press the WX-Alert button again.
Weather mode with Weather Alert Watch
Because weather mode already monitors the weather channels, you don’t need Weather Alert Watch to check the weather channel every seven seconds. If you activate Weather Alert Watch while operating in weather mode, it operates as a type of “sleep mode”: the radio stays on the weather channel and mutes the speaker. If an alert is detected, the radio sounds an alert tone and turns the speaker back on. This mode is very useful when you are anchoring for the night but want to keep informed of hazards.
Weather mode with Triple Watch or Dual Watch
If you activate Triple Watch while operating in weather mode, the radio checks channels 16 and 9 every two seconds; with Dual Watch turned on, the radio only checks channel 16.
Setting Up the Hardware
Attaching the antenna
The antenna detaches from the radio for easy shipping or storage. To attach the antenna to your radio, screw it tightly onto the anchor post at the top of the radio.
Installing the battery
Your MHS75 comes with a rechargeable Lithium Ion battery; for shipping safety, the battery is not installed at the factory.
- Insert the hook on the battery into the notch at the top of the battery compartment.
Note: Each time you remove the battery, check the rubber seal around the battery compartment. Make sure the seal is seated in the groove and there is no dirt or debris on it. If the seal looks worn or damaged, contact customer service to order a replacement (see back cover page for contact information).
- Lower the battery until it rests flat in the compartment.
- Bring the battery latch up and snap it into place.
Charging the battery
Connecting the charger
Align the charger with the battery (on the rear side of the radio). Slide the radio into the charger until it clicks into place. Connect the other end of the charger to any standard 12 volt DC “cigarette lighter” style outlet. The power LED on the top of the plug should turn orange and remain lit.
CAUTION: If the LED blinks, immediately disconnect the charger from the DC outlet. Reseat the radio in the charger before reconnecting the charger to power.
CAUTION: Use only the battery and charger supplied with this radio. Using a different charger or battery can damage the radio and create a risk of fire or shock.
Important notes on charging the battery
- Charge the battery fully before using the radio.
- When the battery is completely charged, the power LED turns green.
- Don’t use the charger when the ambient temperature is below 0º C (32º F) or above 45º C (113º F).
- If the radio is powered down, the battery can charge in about three and a half hours. (If the radio is powered on, the battery takes longer to charge.)
- If the battery is empty, the radio can’t transmit, even if it’s in the charger.
Be careful moving the charger cord. If you have to move the cord while the radio is charging, pick up the radio first so you don’t drop it.
Disconnecting the charger
Squeeze in on the release tabs at the base of the charger, and slide the radio out.
Attaching the belt clip
To attach the belt clip:
- Rotate the belt clip so that the finger indentation is towards the top of the radio.
- Align the center of the clip with the anchor post.
- Place the clip on the post and slide the clip upwards until it clicks into place.
To remove the belt clip:
- Rotate the clip so that the finger indentation is towards the bottom of the radio.
- Slide the clip up until it comes free of the anchor post.
Using Your Radio
Changing the volume
To increase the speaker volume, turn the Volume-Power knob clockwise; turn it counter-clockwise to decrease the volume.
Setting the squelch level
The squelch feature reduces static on the speaker by filtering out any background channel noise. At the lowest squelch level, the speaker plays all signals, including any channel noise. Setting the squelch level higher filters out noise and lets only actual radio transmissions through.
While listening to a channel, adjust the SQUELCH knob until the noise is filtered and you can hear only the transmission. If you switch to a channel with a lot of noise or a weak transmission, you may need to readjust the squelch level again.
Note: Setting the squelch level too high may prevent you from hearing weaker transmissions. If you are having difficulty hearing a transmission, try setting the squelch level lower.
Changing the channel
Press the Channel Up and Channel Down buttons briefly to scroll through the channels one channel at a time. Press and hold the Channel Up or Channel Down button to quickly scroll through the channels.
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.
- 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.
- For the best sound quality, hold the microphone about two inches away from your mouth.
- See the channel lists starting on page 19 for a list of receive-only channels.
Boosting the transmission power
In most situations, the 1 Watt 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 boost the transmission power from 1 Watt to 2.5 Watts or 5 Watts:
- Press the 1/5W-2.5W button to switch from 1 Watt to 5 Watts. Press the button again to switch back to 1 Watt.
- To switch to 2.5 Watts, press and hold the 1/5W-2.5W button for about two seconds. Press and hold the button again to switch back to 1 Watt or 5 Watts (whichever you were on when you switched to 2.5 Watts).
- The transmit power remains at the new setting until you change it again. The transmit power icon always shows the current transmission power.
Note: Don’t forget to change the transmission setting back to 1 Watt when you move close to other stations.
- Some channels (for example, channels 13 and 67) limit the transmission power to 1 Watt. When you tune to a limited-power channel, the radio automatically switches to 1 Watt. See the channel lists starting on page 19 for a list of power-restricted channels.
Setting the UIC channel mode
The radio comes preset to use the channels assigned for the US. If your current area uses Canadian or international channel assignments, press the UIC-Lock key to rotate through the US, Canadian, and international channels.
Maintenance and Troubleshooting
Due to its rugged design, the MHS75 requires very little maintenance. However, it is a precision electronic instrument, so you should follow a few precautions:
- If the antenna has been damaged, do not transmit except in an emergency situation. Transmitting with a defective antenna may cause further radio damage.
- You are responsible for continued FCC technical compliance of your radio.
- You should arrange for periodic performance checks with your Uniden dealer.
Common questions
Specifications
Channels and Frequencies
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