Bird 43 Thruline Wattmeter
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| Frequency | the CURRENT factory spec table reads 2 MHz - 1.2 GHz and 100 mW - 5 kW for the standard body; the storied '450 kHz - 2.7 GHz / 10 kW' figures describe the wider 43-SERIES element ecosystem and legacy line sections - by element, always |
| Bands | all (with appropriate element) |
| Power | whatever the inserted element says: the famous slugs each cover one power range over one frequency band |
| Modes | forward power, reflected power |
| rf | SO-239 pass-through (in-line) |
| power req | none (passive) |
The reference instrument: when two meters disagree, the Bird is the one believed - a directional coupler of legendary consistency whose plug-in element system means one body covers DC-to-daylight and QRP-to-broadcast as your needs grow. Passive operation, shop-grade build, and a parts ecosystem deeper than some hobbies make it the rare purchase that's genuinely once-per-lifetime.
The element system is also the bill: each band/power combination is its own pricey slug, the +/-5%-of-FULL-SCALE spec means readings low on the dial are proportionally rougher, and it reads CW average only - PEP and digital-mode questions need the optional kit or another instrument. No SWR scale: you compute it from forward and reflected, like your grandfather did.
Not the meter most hams need - the meter all hams trust. Buy one body, accumulate slugs like the heirloom tools they are, and arguments about power end at your bench permanently.
The Bird 43 is less a product than a unit of belief: for some seventy years, 'what does the Bird say?' has been two-way radio's way of ending power arguments. The instrument is a precision Thruline directional line section whose measuring personality lives entirely in plug-in elements - the famous 'slugs' - each a calibrated sampler covering one power range over one frequency band, inserted into the body and rotated 180 degrees to read forward or reflected power. The current factory table rates the standard body at 2 MHz to 1.2 GHz and 100 milliwatts to 5 kilowatts - the storied 450-kHz-to-2.7-GHz, 10-kilowatt numbers describe the wider 43-series element ecosystem and its legacy line sections - all at the spec generations of service shops were audited against: plus-or-minus five percent of full scale.
The design's virtues are vacuum-tube-era field thinking never improved upon: the measurement is passive (the element's sampled RF drives the meter movement directly - no battery, nothing to drift off), the RF connectors are quick-change fittings swappable from the standard N to whatever the bench speaks, and the housing stores two spare elements, one in each cheek. A 1960s body with a healthy element reads today like the day it shipped, which is why hamfests trade slugs like baseball cards and why estate-sale 43s outsell most new meters.
The honest limits define its company: each band/power combination is its own hundred-dollar element, the full-scale accuracy spec means low-dial readings are proportionally rougher, it reads CW average (PEP wants the 4300-400 kit or the 43P variant), and there is no SWR scale - you measure forward, rotate, measure reflected, and compute, as the manual cheerfully assumes you can. The cross-needle convenience class answers those complaints at a third the price and none of the authority; the Bird answers exactly one question, permanently, which is why every serious bench eventually grows one.