AdvancedA-003-006-011
At what line impedance do most RF wattmeters usually operate?
A
Answer
Transmitters and receivers
Type
A
50 ohms
B
300 ohms
C
100 ohms
D
25 ohms
Answer Notes
Most amateur radio transceivers, coaxial cables, and associated equipment are standardized to operate at a characteristic impedance of 50 ohms. Consequently, RF wattmeters are designed and calibrated specifically for 50-ohm lines.
Using a 50-ohm wattmeter on a line with a different impedance, such as 75 ohms or 300 ohms, will cause mismatch errors. This results in inaccurate power and standing wave ratio (SWR) readings, making standard 50-ohm equipment the universal choice for amateur RF measurement.
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For the same transformer secondary voltage, which rectifier has the highest average output voltage?