5-10Gain and Time Constant Menu
Reserve This key selects either maximum, minimum or manual dynamic reserve.
When the reserve is maximum, the SR850 automatically selects the max-
imum reserve available at the present full scale sensitivity. When the
reserve is minimum, the minimum available reserve is selected. The
dynamic reserve is displayed in the settings display at the top of the
screen (if selected in the DISPLAY/SCALE menu).
When the reserve is manual, the reserve is set by the user to a value
between the min and max reserve. The reserve is set in 10 dB
increments.
Changing the sensitivity may change the reserve. With max or min
reserve, the max or min reserve of the new sensitivity is used. With
manual reserve, the reserve is kept the same relative to the mini-
mum reserve. For example, if the sensivity is 10 mV and the reserve is
21 dB (20 dB above the minimum for this sensivity), changing the sensiv-
ity to 5 mV will change the reserve to 27 dB (20 dB above the 7 dB mini-
mum). If the new sensivity does not have a reserve high enough to satis-
fy this rule, then the max sensitivity will be used instead.
The minimum and maximum reserve limits for each sensitivity are listed
below.
Sensitivity Min Reserve (dB) Max Reserve (dB)
1 V 0 0
500 mV 6 6
200 mV 4 14
100 mV 0 20
50 mV 6 26
20 mV 4 34
10 mV 0 40
5 mV 6 46
2 mV 4 54
1 mV 10 60
500 µV 16 66
200 µV 24 74
100 µV 30 80
50 µV 36 86
20 µV 44 94
10 µV 50 100
5 µV 56 106
2 µV 64 114
1 µV 70 120
500 nV 76 126
200 nV 84 134
100 nV 90 140
50 nV 96 146
20 nV 104 154
10 nV 110 160
5 nV 116 166
2 nV 124 174
Do not use ultra high dynamic reserves above 120 dB unless absolutely
necessary. It will be very likely that the noise floor of any interfering