HAM - Radio Extra Class Test Radio Extra Class General 1

Question 1

What is the lowest frequency on the 40-meter band on which an Amateur Extra class licensee may operate SSB voice?

Accepted Answer

7.125 MHz

Answer

Amateur Extra class licensees hold phone (SSB/voice) privileges beginning at 7.125 MHz on the 40-meter band. General class licensees may only use phone down to 7.175 MHz, so the 7.125–7.175 MHz segment is exclusive to Extra (and Advanced) class operators.

Question 2

Which mode of propagation is responsible for extending 2-meter VHF signals over 1,000 miles or more during periods of stable high-pressure weather systems?

Accepted Answer

Tropospheric ducting

Answer

Tropospheric ducting occurs when a temperature inversion in the lower atmosphere traps VHF/UHF signals, acting like a waveguide that can carry signals for hundreds to thousands of miles. It is most common during stable, warm, high-pressure conditions.

Question 3

What is the approximate symbol rate of a PSK31 digital mode signal?

Accepted Answer

31.25 baud

Answer

PSK31 (Phase Shift Keying, 31 baud) uses a symbol rate of approximately 31.25 baud. This extremely slow rate gives PSK31 a bandwidth of roughly 31 Hz, making it one of the narrowest and most spectrum-efficient HF digital modes.

Question 4

How does the radiation resistance of a folded dipole compare to that of a standard half-wave dipole?

Accepted Answer

It is four times as high, approximately 292 ohms

Answer

A folded dipole has a radiation resistance of approximately 292 ohms—four times that of a standard half-wave dipole (~73 ohms). The two parallel conductors share the driven current, and the impedance transformation results in a 4:1 ratio, making the folded dipole a natural match for 300-ohm twin-lead feedline.

Question 5

What is the primary purpose of a key-click filter in a CW transmitter?

Accepted Answer

To smooth the rise and fall times of keyed pulses, reducing occupied bandwidth

Answer

Abrupt transitions between the on and off states of a CW signal generate broad sidebands known as key clicks that can interfere with adjacent stations. A key-click filter shapes the envelope so that rise and fall times are gradual (typically a few milliseconds), greatly reducing the occupied bandwidth.

HAM - Radio Extra Class Test Practice Test

HAM - Radio Extra Class Test Practice Test

HAM - Radio Extra Class Test Radio Extra Class General 1