Owner's manual

Page 2 of 3 7/13/05 921-4030
Theory of Operation
Normally, field strength meters have resonant reactive networks where the RF signal is detected and then
rectified to a half-wave current. This signal is then indicated on a sensitive microammeter. This method, of
course, is limited and not very useful for weak signals.
The Bird 4030 Field Strength Element uses a broad-band nonreactive solid state circuit. This circuit
amplifies the detected RF signal and delivers a dc voltage to the microammeter proportioned to the signal
magnitude. The amplification is regulated by the gain control allowing the unit to be used for very low to high
RF signal conditions.
Operation
The Bird 4030 and THRULINE
®
Wattmeter combination is very simple to operate. There is only one control,
the GAIN CONTROL on the front face of the unit, which is also the ON/OFF switch. Follow the steps below
for proper operation.
1. Turn the gain control slightly clockwise until it clicks on. Place the unit several feet from the
transmitting antenna.
2. Turn on the RF power and adjust the gain on the 4030 until the pointer is about half of fullscale. If
the pointer does not move significantly, move the unit closer to the antenna.
3. Adjust the antenna and/or transmitter output according to the manufacturers instructions to get the
maximum possible reading on the meter.
4. When done, return the gain control to the OFF position.
 NOTE: For maximum battery life, turn the 4030 OFF when not using it.
Battery Cup
Battery Cup,
Removed
DC Contact
Gain Control
&
On/Off Switch
Ground
Contact
A
ntenna