B-006-06: Concept of impedance matching
B-006-06-01:
What device might allow use of an antenna on a band it was not designed for?
An antenna tuner
An SWR meter
A low pass filter
A high pass filter
B-006-06-02:
What does an antenna matching unit do?
It matches a transceiver to a mismatched antenna system
It helps a receiver automatically tune in stations that are far away
It switches an antenna system to a transmitter when sending, and to a receiver when listening
It switches a transceiver between different kinds of antennas connected to one feed line
B-006-06-03:
What would you use to connect a coaxial cable of 50 ohms impedance to an antenna of 35 ohms impedance?
An impedance-matching device
An SWR meter
A low pass filter
A terminating resistor
B-006-06-04:
When will a power source deliver maximum output to the load?
When the impedance of the load is equal to the impedance of the source
When air wound transformers are used instead of iron-core transformers
When the power-supply fuse rating equals the primary winding current
When the load resistance is infinite
B-006-06-05:
What happens when the impedance of an electrical load is equal to the internal impedance of the power source?
The source delivers maximum power to the load
The electrical load is shorted
No current can flow through the circuit
The source delivers minimum power to the load
B-006-06-06:
Why is impedance matching important?
So the source can deliver maximum power to the load
So the load will draw minimum power from the source
To ensure that there is less resistance than reactance in the circuit
To ensure that the resistance and reactance in the circuit are equal
B-006-06-07:
To obtain efficient power transmission from a transmitter to an antenna requires:
matching of impedances
high load impedance
low ohmic resistance
inductive impedance
B-006-06-08:
To obtain efficient transfer of power from a transmitter to an antenna, it is important that there is a:
matching of impedance
high load impedance
proper method of balance
low ohmic resistance
B-006-06-09:
If an antenna is correctly matched to a transmitter, the length of transmission line:
will have no effect on the matching
must be a full wavelength long
must be an odd number of quarter-wave
must be an even number of half-waves
B-006-06-10:
The reason that an RF transmission line should be matched at the transmitter end is to:
transfer the maximum amount of power to the antenna
ensure that the radiated signal has the intended polarization
prevent frequency drift
overcome fading of the transmitted signal
B-006-06-11:
If the centre impedance of a folded dipole is approximately 300 ohms, and you are using RG8U (50 ohms) coaxial lines, what is the ratio required to have the line and the antenna matched?
6:1
2:1
4:1
10:1
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