VHF radio (Simrad® RT64 as prototype)

Features :
  • display and button backlighting
  • user channel
  • channel transmit power 1 or 25W
  • dual watch and tri-watch modes
  • scan
  • scan of selected channels
  • squelch, volume and channel rotary controls
  • fistmike with PTT (push-to-talk) and select channel buttons
  • Function How to implement
    switch on rotate volume knob clockwise.
    switch off rotate volume knob fully counterclockwise.
    backlighting press [F] button to switch to the "second function" mode. Successively click [F] to change backlighting level.
    channel selection rotate channel knob clockwise to scroll VHF channels up, counterclockwise to scroll down. Also use the upper and lower buttons of the fistmike.
    changing channel transmission power press [1/25] button.
    dual watch dual watch can be started by pressing [D/W]. Then, currently selected channel and the priority channel will enter the scan sequence. In case of priority channel currently selected, dual watch is not possible and [DW] switches to previously selected (not priority) channel. Stop dual watch by pressing [D/W], [16] or rotate channel knob counterclockwise.
    tri-watch this scan mode is similar to dual watch, but the three channels are scanned instead of two, namely current channel, priority channel (16) and user channel. Start tri-watch by holding down [D/W] for 2 seconds. Stop tri-watch by pressing [D/W], [16] or rotate channel knob counterclockwise.
    selecting user channel user channel used in tri-watch scan can be selected by the following procedure. Select the channel, press [F], then press and hold [16]. After 2 seconds the new user channel will be selected. If user channel is currently selected, the display shows "USE" sign.
    scan (all channels) all (not inhibited) channels are scanned one by one until a signal above the current squelch level is detected. Start scan by pressing [SCN] button. Stop scan by pressing [SCN] again, [16], or turning the channel knob counterclockwise.
    excluding channels from scan sequence if a channel has a lot of interference noise, it would cause scans lock onto this channel. To exclude such a channel from scan sequence, a channel can be inhibited. Press [F] then [D/W] to inhibit the selected channel (the display will show INH ofr such channels), or press [F] plus [D/W] again to enable a currently selected channel (the display shows ENA).
    scan memory (selected channels) a set of selected channels can be specified and this sequence scanned. To add a new channel into the scan memory, select a channel and press [F] then [1/25]. If such channel is already in memory, it will be deleted. Start scan by pressing [F] plus [SCN] button. Stop scan by pressing [SCN] again, [16], or turning the channel knob counterclockwise.
    setting squelch level SQL knob is used to set squelch level (receiver muting threshold) to suppress interference noise. Note that during a scan the noise may lock a channel, so usually scanning can proceed with squelch level increased to a certain value.
    transmitting stop all scans, set a channel and press the PTT (Push-To-Talk) button on the microphone. Hold down the button while you speak. To be heard from another ship equipped with another VHF radio, you must be not farther away than roughly 20NM, and the receiving VHF radio must hold the receiving (RX) frequency equal to transmitting (TX) frequency of the transmitting radio. Specifically, it means that the communication is OK when the two parties communicate on the same SIMPLEX (equal TX and RX frequencies) VHF working channel. Communications between ships are not possible on duplex channels, which have different RX and TX frequencies.
    priority channel priority channel (16) is used for transmitting distress messages only. To quickly set this channel, press [16]. Routine communications are prohibited on this channel.