ORAE Class B Part 08 - Interference

What is the purpose of the "notch filter" found on many HF transceivers?

• To restrict the transmitter voice bandwidth

• To reduce interference from carriers in the receiver passband

• To eliminate receiver interference from impulse noise sources

• To enhance the reception of a specific frequency on a crowded band

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What is one advantage of selecting the opposite or "reverse" sideband when receiving CW signals on a typical HF transceiver?

• Interference from impulse noise will be eliminated

• More stations can be accommodated within a given signal passband

• It may be possible to reduce or eliminate interference from other signals

• Accidental out of band operation can be prevented

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What is normally meant by operating a transceiver in "split" mode?

• The radio is operating at half power

• The transceiver is operating from an external power source

• The transceiver is set to different transmit and receive frequencies

• The transmitter is emitting an SSB signal, as opposed to DSB operation

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What reading on the plate current meter of a vacuum tube RF power amplifier indicates correct adjustment of the plate tuning control?

• A pronounced peak

• A pronounced dip

• No change will be observed

• A slow, rhythmic oscillation

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What is a reason to use Automatic Level Control (ALC) with an RF power amplifier?

• To balance the transmitter audio frequency response

• To reduce harmonic radiation

• To reduce distortion due to excessive drive

• To increase overall efficiency

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What type of device is often used to match transmitter output impedance to an impedance not equal to 50 ohms?

• Balanced modulator

• SWR Bridge

• Antenna coupler or antenna tuner

• Q-Multiplier

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What condition can lead to permanent damage to a solid-state RF power amplifier?

• Insufficient drive power

• Low input SWR

• Shorting the input signal to ground

• Excessive drive power

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What is the correct adjustment for the load or coupling control of a vacuum tube RF power amplifier?

• Minimum SWR on the antenna

• Minimum plate current without exceeding maximum allowable grid current

• Highest plate voltage while minimising grid current

• Maximum power output without exceeding maximum allowable plate current

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

Why is a time delay sometimes included in a transmitter keying circuit?

• To prevent stations from interfering with one another

• To allow the transmitter power regulators to charge properly

• To allow time for transmit-receive changeover operations to complete properly before RF output is allowed

• To allow time for a warning signal to be sent to other stations

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A

What is the purpose of an electronic keyer?

• Automatic transmit/receive switching

• Automatic generation of strings of dots and dashes for CW operation

• VOX operation

• Computer interfaces for PSK and RTTY operation

Answer explanation

https://hamstudy.org/browse/E3_2019/G4A