ESCO Technologies ETS Lindgren 3301B, User Manual

Page: 19 / 56

Principles of Operation | 19
6.0 Principles of Operation
6.1 Description
The ETS-Lindgren Model 3301B electric field receiving antenna is composed of
three principal sections: a sensing rod, a ground plane or counterpoise, and a
broadband, high input impedance pre-amplifier.
The rod and counterpoise function together as an electrically short antenna over
ground plane. The pre-amplifier provides impedance transformation from the
extremely high impedance at the base of the rod to the 50 ohms required by
most receiving systems, and provides power gain to allow the sensing of very low
level signals.
6.2 Front Panel
On the front panel of the Model 3301B are the following:
•
Power switch
•
Gain switch
•
Saturation indicator
•
Battery Low/Power On indicator
•
BNC Output port
•
Battery Charging port
P
OWER
S
WITCH
The power switch is located on the lower right of the front panel. Activating the
power switch will turn on the Battery Low/Power On indicator (green).
B
ATTERY
L
OW
/P
OWER
O
N
I
NDICATOR
The Battery Low/Power On indicator is controlled by a voltage monitor circuit. If
the green indicator does not turn on, or if it turns off during use, the battery
requires charging.
G
AIN
S
WITCH
In the middle left is the Gain switch, which increases the voltage output of the
gain stage in the amplifier by 10 dB. However, best sensitivity is achieved in the
low gain setting. The gain option provides additional output power for test
situations that require additional output.