Humminbird DC 25 User Manual
What You Need
Your Humminbird VHF radio requires the connection of a VHF marine band antenna. These
antennas are readily available through marine distributors and come in a variety of shapes,
materials, and mounting types.
A high Quality antenna will maximize your transmit range and reception clarity, and compliment
your Humminbird VHF radio.
You can use your Humminbird VHF radio with any other quality marine band antenna . If you
intend to use a previously installed antenna, check it before installing your radio to make sure all
connections are tight and free of corrosion.
Note: Do not operate the Humminbird VHF radio without an antenna, or with a “CB” antenna.
Attempting to do so may damage the unit. Humminbird is not responsible for damages caused by
operation without an antenna or with an inappropriate antenna.
In addition to the antenna options listed previously, Humminbird offers the following optional
accessory for your VHF radio.
Accessory Part No. Use
Speaker adapter SAC-R Allows
Cable connection of
External speaker
For more information on these accessories, contact your local Humminbird dealer or call our tollfree Customer Support Hotline.
OBTAINING APPROPRIATE LICENSES
Before operating your Humminbird VHF radio, you must apply for the appropriat e licenses. For
your convenience, the product box includes license applications that you can fill out and mail as
instructed on each application.
Ship Station License
Any craft equipped with a VHF/FM transceiver (such as your Humminbird VHF radio) is
considered a Ship Station, and must carry a current Ship Station License. It is unlawful to operate
an unlicensed Ship Station. Your license will state the call sign, which is your craft’s identification
for radio purposes.
Be sure to complete and mail the Ship Radiotelephone License application (FCC Form 506A),
provided with your Humminbird VHF radio. You may obtain an interim Ship’s Stations license by
appearing in person at your local FCC Field Office.
Operator’s License
In the U.S., you may need to apply for a Restricted Radiotelephone Operator Permit, or higher
grade license, before operating your Humminbird VHF radio. (The operator’s license is not
required for voluntary equipped vessels on domestic voyages. To apply, complete and mail FCC
Form 753, provided with your Humminbird VHF radio. An interim permit is automatically granted
upon submission of the application. Other countries may have specific licensing requirements.
Installing The VHF Radio
Installation Location
The first step in installing the Humminbird VHF radio is to determine the best mounting location.
The gimbal mount included with your radio offers mounting capabilities for the top or bottom of a
shelf, the bulkhead, or overhead. The radio can be tilted up or down on its mount to allow
maximum ease of viewing and operation.
To choose the best location for installation, consider the following:
• The mounting surface must be adequately supported to protect the radio from excess wave
shock and vibration.
• The mounting area should allow at least 2” clearance at the back of the unit for connectors
and air flow.
• Do not mount the radio within 12” of your compass (due to the magnet in the built-in
speaker). Similarly, if you are mounting an auxiliary speaker, keep it away from the compass.
• Any depth sounder will create some degree of radio interference (which Humminbird depth
sounders are designed to minimize) through the antenna cable. To further minimize potential
interference, route the antenna and transducer cables as far away from each other as
possible- for example, on opposite sides of the boat. A “rubber duckie” antenna is less prone
to interference than longer-range, cabled antennas.
• Keep all cable runs away from electrical pumps, depth sounders, generators, and other
electronic instruments.
• Do not mount vertically- water may collect in the speaker grille and distort sound.
• Interference may also be created by the alternator, bilge pump and other devices. If this
causes a problem- connect the radio to an alternative power source.
When mounting your antenna, refer to the instructions included with it to determine the best
antenna location. The antenna should be located away from metal objects. Mounting the
base of the antenna higher than the depth sounder will reduce the potential for interference.
Mounting the antenna as high above the water line as possible ensures the greatest range of
reception and transmission.
Installing the Gimbal Mount and Radio
After you have determined the best location for your VHF radio, proceed as follows:
1. Set the gimbal mount on the mounting surface.
2. Mark 1/16” starting holes for the mounting screws.
3. At least 6” behind the bracket, mark a ¾” hole to run the cables through.
4. Set the gimbal mount aside and drill the holes as marked.
5. Mount the bracket, using the mounting hardware supplied with your VHF radio.
6. To connect the power cable to the 12-volt DC power source, wire the VHF radio through
your fuse panel with the supplied 6-amp fuse. If your boat does not have a fuse panel,
you can wire the power cable to the battery with the 6-amp fuse and fuse holder (also
supplied) in the positive wire, as shown to the right.
Note: Do not use any power cable other than the one provided with your VHF radio.
7. Pull the power cable, antenna cable, and cable for the auxiliary speaker (if used) up
through the ¾” hole behind the gimbal bracket, leaving the connector ends above the
mounting surface.
8. Connect the cables to the appropriate cable plugs at the back of the VHF radio.
9. To “dress” the ¾” hole and hold the power cable securely, push any excess cable down
into the hole, and install the hole cover provided with your VHF radio.
10. Mount the VHF radio on the gimbal bracket by loosening the mounting knobs and
slipping the unit into the brac ket. Be sure to keep the rubber washers between the
bracket and the unit. Tighten the knobs to hold the radio in the operating position.
Installing the Microphone Holder
Finally, install the microphone holder near the VHF radio, on any vertical surface:
1. Position the microphone holder near the VHF radio on any vertical surface.
2. Mark 1/16” starting holes for the mounting screws.
3. Set the microphone mount aside and drill the starting holes as marked.
4. Mount the microphone holder, using the screws supplied with your VHF radio.
5. Place the microphone in its holder.
Installing the Antenna
If you have not already done so, install your antenna according to the instructions included with
it. For additional tips on mounting locations, see “Installation Location” earlier in this manual.
Note: Do not operate the Humminbird VHF radio without a 50-ohm marine band antenna.
Attempting to do so may damage the unit. Humminbird is not responsible for damages caused by
operation without an antenna or with an inappropriate antenna.
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