Garmin VHF 315 Owners Manual PDF - Page 7

Switching to Priority Channels You can quickly switch between your current working channel and a priority channel. When you change to a priority channel, the transmit power is set to high (25 W) automatically, and when you change back to your current channel, the transmit-power setting is restored. On North American models, you can quickly switch between channel 16, your second-priority channel, and your original channel using the 16/9 key. On International models, you can quickly switch between channel 16 and your original channel using the 16+ key. 1 To switch from your current channel to channel 16, select 16/9 or 16+. The transmit power changes to high (25 W) automatically. You can select HI/LO > 1W to change the transmit power to low (1 W). 2 On North American models, select 16/9 to switch to your second-priority channel. 3 Select 16/9 or 16+ to return to your previous channel and transmit-power setting. Setting the Receiving Sensitivity You can control the receiving sensitivity of the radio. When you have noise in high-traffic areas or areas with electromagnetic interference, such as near cell-phone towers, you can set the receiving sensitivity to LOC to decrease receiver sensitivity. In remote areas and on open water, you can set the receiving sensitivity to DIST to ensure that you use the maximum range of the receiver. 1 Select HI/LO. 2 Select an option: • Select LOC to enable local sensitivity. • Select DIST to enable distant sensitivity. Switching Between 1 W and 25 W Transmitting Modes You can control the transmitting power of the radio. Low (1 W) is used for local transmissions, and high (25 W) is used for distance and distress transmissions. When two signals broadcast on the same frequency, a VHF radio receives only the stronger of the two signals. You should transmit calls other than distress calls using the lowest power setting that allows you to communicate, to reduce the possibility that your transmissions interfere with the transmissions of others. In the USA frequency band, transmissions on channels 13 and 67 must be low (1 W) by default. You can bypass the power setting temporarily during transmission (Bypassing the Low Transmission Power Setting, page 3). In the International channel band, transmissions on channels 15 and 17 must be low (1 W), and the radio does not allow transmissions on these channels to be changed to high (25 W). 1 Select HI/LO. 2 Select 1W or 25W. 3 Select OK. Bypassing the Low Transmission Power Setting In the USA frequency band, transmissions on channels 13 and 67 are required to be low-power (1 W) by default, because they are intended for intership (bridge-to-bridge) communication. If other radios cannot receive these channels due to the low power setting, you can bypass the default restriction. 1 From USA channels 13 or 67, select PTT. 2 While transmitting, select 25W. Using the Hailer Function Before you can use the hailer function, you must install a hailer horn (optional). For more information, see the VHF 315 Series Installation Instructions. A hailer horn allows you to make on-boat or ship-to-shore announcements, and allows two-way communications between connected radios. You can address the ship using the radio or handset, and sounds received through the horn can be heard through the radio speaker. For vessels with enclosed cabins, the hailer horn allows you to hear sounds from the deck. NOTE: When the radio is in hailer mode, it does not receive broadcasts from the active channel. 1 Select PA > HAILER. Sounds received through the horn are heard through the radio speaker. 2 Hold PTT. 3 Select an option: • To make an announcement, speak into the handset. • To adjust the volume of the hailer broadcast, turn the ENTER dial. 4 Release PTT to stop broadcasting and listen for broadcasts from other connected radios on the ship. Foghorn NOTE: Foghorn functionality is not available on all VHF radio models. Before you can use the foghorn, you must provide and install a hailer horn (optional) on the deck or tower of your boat. For more information, see the VHF 315 Series Installation Instructions. The foghorn is part of the public address system of your radio. You can sound the foghorn through a hailer horn or an external speaker. Your radio can sound the horn automatically using standard patterns, or you can sound the horn manually. When you manually operate the foghorn, sounds received through the horn can be heard through the radio speaker between soundings. Sounding the Foghorn Automatically 1 Select PA > FOG > AUTO. 2 Select a foghorn-type option. The radio alternates between sounding the pattern of tones or rings and receiving radio broadcasts. 3 Turn the ENTER dial to adjust the volume of the horn (optional). Sounding the Foghorn Manually NOTE: When you sound the horn manually, the radio does not receive broadcasts between horn soundings. 1 Select PA > FOG > MANUAL. Sounds are received through the horn and heard through the radio speaker. 2 Hold PTT. NOTE: The horn stops sounding when you release PTT. 3 Turn the ENTER dial to adjust the volume of the horn (optional). Adjusting the Sound Frequency of the Foghorn You can increase or decrease the sound frequency of the foghorn. The pitch of the tone rises with an increase in frequency, and falls with a decrease in frequency. The minimum setting is 200 Hz, and the maximum setting is 850 Hz. The default setting is 350 Hz. Regulations dictate the correct frequency of foghorns, which correlate with the size of your vessel. Basic Operation 3