Standing Wave Ratio and Antenna Measurements Flashcards
What, in general terms, is standing wave ratio (SWR)? (T7C03)
A measure of how well a load is matched to a transmission line
What reading on an SWR meter indicates a perfect impedance match between the antenna and the feed line? (T7C04)
1 to 1
What does an SWR reading of 4:1 indicate (T7C06)
Impedance mismatch
Why is it important to have low SWR when using coaxial cable feed line? (T9B01)
To reduce signal loss
What happens to power lost in a feed line? (T7C07)
It is converted into heat
What is the proper location for an external SWR meter? (T4A05)
In series with the feed line, between the transmitter and antenna
Why do most solid-state amateur radio transmitters reduce output power as SWR increases? (T7C05)
To protect the output amplifier transistors
What instrument other than an SWR meter could you use to determine if a feed line and antenna are properly matched? (T7C08)
Directional wattmeter
Which of the following instruments can be used to determine if an antenna is resonant at the desired operating frequency? (T7C02)
An antenna analyzer
What is the major function of an antenna tuner (antenna coupler)? (T9B04)
It matches the antenna system impedance to the transceiver’s output impedance
What is the primary purpose of a dummy load? (T7C01)
To prevent transmitting signals over the air when making tests
What does a dummy load consist of? (T7C12)
A non-inductive resistor and a heat sink
