921-4300-400 Rev B 4/15/2010 Page 1 of 5
Introduction
The Bird Model 4300-400 modification kit is designed for easy installation in any Bird Model 43 Wattmeter to
convert the instrument to read peak power in AM, SSB, and certain limited pulse applications. Installation of
the kit does not affect the model 43’s ability to read CW power (no amplitude modulation).
No special elements are required for peak power measurements. However, element power ratings must match
the peak power to be read. For example, if power output peaks of 1000 W are to be measured, a 1000 W ele-
ment should be used in the meter.
How to Use
After the 4300-400 kit is installed, there will be a PUSH ON - PUSH OFF switch on the right hand side of the
meter. To read PEAK, push the switch in and note the red Light Emitting Diode (LED) lights up. The meter
will now read peak power.
To read CW (no AM modulation), push the switch in again to OFF. Note that the red LED is no longer lit. The
meter will once again function as a CW reading Model 43.
Peak Detector Response
The electrical time constant of the peak detector circuit is set at one second, although the actual response
time may be slightly longer than this due to meter damping. Therefore, a short delay may be noticed between
the time that the transmitter is energized and the meter reading stabilizes. This delay will also be noticed
upon transmitter de-energization as the meter needle sweeps back to zero. Additionally, the meter reading
may be expected to waver approximately 2-3 minor scale divisions when voice modulation is used, as the peak
detector attempts to follow peak power variations associated with voice modulation.
Bird Model 43P Specifications (Model 4300-400 Modification Kit installed)
RF Frequency Range 0.450 2300 MHz, depending on element selected
RF Power Range 100 mW to 10 kW, depending on element selected
Accuracy
a
a.When measuring pulse power, the following parameters must be observed:
Duty Cycle - 2% minimum
Rep. Rate - 100 pps minimum
Pulse Width - 200 μsec. minimum
CW mode ±5% of full scale
PEP mode ±8% of full scale
Power Requirement (2) 9 V alkaline batteries (NEDA 1604)
Battery Life Approx 48 operating hours
Weight:
Model Kit Only
Installed on Model 43
Approx 1 lb with batteries
Approx 4 lb (1.8 kg)
Model 4300-400
Modification Kit
Phillips is a registered trademark of
Phillips Screw Company
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