Garmin GDL 88 manual Look

Radar Altitude	GPS Phase	RA, HAT, and	Sensitivity	Look-	Vertical	Minimum
(RA) or Height	of Flight	GPS Flight	Level	Ahead	Threshold	Protected
Above Terrain		Phase Not		Time(s)	for Alarm	Volume
(HAT)		Available			(feet)	(NM)
(if Available)		OR
		GPS
		Phase of
		Flight Not
		Approach or
		Terminal
Up to 1000	Approach	N/A	2	20	850	0.20
(RA or HAT)
1000-2350	Terminal	N/A	3	25	850	0.20
(RA or HAT)
2350-5000		Below	4	30	850	0.35
(Geodetic)		5000
		(Geodetic)
5000-10,000		5000-	5	40	850	0.55
(Geodetic)		10,000
		(Geodetic)
10,000-		10,000-	6	45	850	0.80
20,000		20,000
(Geodetic)		(Geodetic)
20,000-		20,000-	7	48	850	1.10
42,000		42,000
(Geodetic)		(Geodetic)
Above 42,000		Above	8	48	1200	1.10
(Geodetic)		42,000
		(Geodetic)
	Table 4-2 Traffic Alert Functionality

190-01122-03 Rev. A GDL 88 ADS-B Transceiver Pilot’s Guide 4-7