Instruction Sheet
Bird 4030 Relative Field
Strength Element
Introduction
The Bird 4030 Relative Field Strength Element is used with Bird 43, 4430 or 4431 Wattmeters. It plugs into
the line section like a standard element, however applying RF power to the line section is not necessary. The
4030 is a self-contained unit that transforms a wattmeter into an ultrasensitive broad-band instrument for
checking relative RF field intensity. Its nonreactive solid state circuitry is sensitive enough to detect even low
level RF signal emission.
The primary use of the Model 4030 is tuning antennas and output stages of base or handheld transceivers. It
can also be used to adjust the output of garage door openers, radio control transmitters or other transmitting
devices with frequencies within the 1 to 1000 MHz frequency range.
Installation
CAUTION
No RF line connections are required for the Bird 4030.
Do not apply power to the RF section.
The Bird 4030 is compatible with and may be used in all Bird THRULINE
movement and that use standard or peak type elements. If a peak-reading wattmeter is used, the wattmeter
must not be in peak mode.
Insert the 4030 in the wattmeter line section so that the text on it is upright, with the locating pins against
the steps in the socket. When fully inserted, it will not rotate.
Do not connect
®
Wattmeters with a 30 µA meter
to RF line
921-4030 7/13/05 Page 1 of 3
Theory of Operation
&
A
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.
ntenna
Ground
Contact
Operation
The Bird 4030 and THRULINE
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.
®
Wattmeter combination is very simple to operate. There is only one control,
Gain Control
On/Off Switch
DC Contact
Battery Cup
Battery Cup,
Removed
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.
Page 2 of 3 7/13/05 921-4030
Maintenance
The only maintenance the Bird 4030 requires is occasional battery replacement. To replace the batteries:
Requirement: Three 3 volt Lithium cells, Bird P/N 5-1475-1, or equivalent
1. Hold the 4030 with both hands and “break off” the gold plated battery cup - it is a tight snap fit. Don't
try to pull the battery cup straight off! Do not lose the insulating sleeve that lines the cup.
2. Replace the three cells with their negative sides toward the bottom of the cup. Do note get finger
grease (skin oil) on the cells, the cup bottom, or the contacting spring. Wipe the contact surfaces
carefully with a clean cloth if necessary.
3. Snap the battery cup back on, then rotate it to assure proper seating.
Specifications
Frequency Range 1 – 1000 MHz
Typical Sensitivity (Gain at full) 1 W @ 150 MHz radiated power from a CW
source will cause a full-scale deflection at a
distance of eight feet.
Output Characteristics Compatible with 30 µA meters
Temperature
Operating
Storage
0 to 50 °C (32 to 122 °F)
–20 to +50 °C (–4 to +122 °F)
Dynamic Range (Gain Control) 30 dB nominal
Battery Three 3V Lithium-Manganese Dioxide cells
100 hour min. life
Dimensions (excluding antenna) 2” H x 1.7” Dia. max. (51 x 44 mm)
Weight, including batteries 3 oz. (0.85 g) nominal
921-4030 7/13/05 Page 3 of 3
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