NorthStar Navigation Explorer 721US Info, To-Noise Ratio SNR, Shown on the LCD, + Ch, Rapidly

info	Information. Press on the base MIKE to toggle through the INFO display to show
	the barometric historgram, the barometric readout and temperature, or the Signal-
	to-Noise Ratio (SNR).
H/L	Transmission Power. High (HI) 25 W or Low (LO) 1 W. Press to toggle between high
	or low transmission power for the entire channel bank. The HI or LO selection is
	shown on the LCD.
	Some channels allow only low power transmissions. Error beeps will sound if the
	power transmission setting is incorrect.
	Some channels allow only low power transmissions initially, but can be changed
	to high power by holding down H/L and PTT at the same time. See Appendix C for
	a complete listing of channel charts.
+ CH -	Channel Select. Press CH + or CH - to step through the available channels one at a
	time, or hold down to scroll rapidly through all the available channels. The current
	channel is shown on the LCD in BIG digits with an A or B designator suffix (if ap-
	plicable) in small letters below the channel number. (See Appendix C for a listing
	of channel frequencies.)
	Press CH + or CH - to scroll the cursor up and down menu options on the LCD when
	navigating menus.
	When editing an item containing only numbers, press CH - to step through the
	numbers or hold down to scroll rapidly.
	To enter a character, press Ch = to step through the alphabet or hold down to scroll
	rapidly.
ENT	Enter. Press ENT when navigating menus, to confirm entries and edits.
PTT	Press To Talk. Press PTT to transmit at any time on an allowable channel. This auto-
	matically exits you from menu mode and stops scanning.
	You must release PTT to receive a signal.
	If PTT sticks, a built-in timer will automatically shut down a transmission after five
	minutes and sound the error beeps. This timer is required by FCC regulations.

12 Northstar Explorer VHF Series: 721US, 721EU Operation and Installation Manual