Chapter 7 Exam Primer

What type of propagation usually occurs from one hand- held VHF transceiver to another nearby?

How does the range of sky-wave propagation compare to ground- wave propagation?

When a signal is returned to earth by the ionosphere, what is this called?

How are VHF signals propagated within the range of the visible horizon?

Skywave is another name for:

That portion of the radiation which is directly affected by the surface of the earth is called:

At HF frequencies, line-of-sight transmission between two stations uses mainly the:

The distance travelled by ground waves:

Reception of high frequency (HF) radio waves beyond 4000 km is generally possible by:

What causes the ionosphere to form?

What type of solar radiation is most responsible for ionization in the outer atmosphere?

Which ionospheric region is closest to the earth?

Which region of the ionosphere is the least useful for long distance radio-wave propagation?

What two sub-regions of ionosphere exist only in the daytime?

When is the ionosphere most ionized?

When is the ionosphere least ionized?

Why is the F2 region mainly responsible for the longest distance radio-wave propagation?

What is the main reason the 160, 80 and 40 metre amateur bands tend to be useful only for shortdistance communications during daylight hours?

During the day, one of the ionospheric layers splits into two parts called:

The position of the E layer in the ionosphere is:

What is a skip zone?

What is the maximum distance along the earth's surface that is normally covered in one hop using the F2 region?

What is the maximum distance along the earth's surface that is normally covered in one hop using the E region?

Skip zone is:

The distance to Europe from your location is approximately 5000 km. What sort of propagation is the most likely to be involved?

For radio signals, the skip distance is determined by the

The distance from the transmitter to the nearest point where the sky wave returns to the earth is called the:

Skip distance is the:

The skip distance of a sky wave will be greatest when the:

If the height of the reflecting layer of the ionosphere increases, the skip distance of a high frequency (HF) transmission

What effect does the D region of the ionosphere have on lower frequency HF signals in the daytime?

What causes the ionosphere to absorb radio waves?

Wo or more parts of the radio wave follow different paths during propagation and this may result in phase differences at the receiver. This "change" at the receiver is called:

A change or variation in signal strength at the antenna, caused by differences in path lengths, is called:

When a transmitted radio signal reaches a station by a one-hop and two-hop skip path, small changes in the ionosphere can cause:

The usual effect of ionospheric storms is to

On the VHF and UHF bands, polarization of the receiving antenna is very important in relation to the transmitting antenna, yet on HF bands it is relatively unimportant. Why is that so?

What causes selective fading?

Ow does the bandwidth of a transmitted signal affect selective fading?

Polarization change often takes place on radio waves that are propagated over long distances. Which of these does not cause polarization change

Reflection of a SSB transmission from the ionosphere causes:

How do sunspots change the ionization of the atmosphere?

How long is an average sunspot cycle?

What is solar flux?

What is the solar-flux index?

What influences all radiocommunication beyond ground-wave or line-of-sight ranges?

Which two types of radiation from the sun influence propagation?

When sunspot numbers are high, how is the ionosphere affected?

All communication frequencies throughout the spectrum are affected in varying degrees by the:

Average duration of a solar cycle is:

The ability of the ionosphere to reflect high frequency radio signals depends on:

Propagation cycles have a period of approximately 11:

What happens to signals higher in frequency than the critical frequency?

What causes the maximum usable frequency to vary?

What does maximum usable frequency mean?

What can be done at an amateur station to continue HF communications during a sudden ionospheric disturbance?

What is one way to determine if the maximum usable frequency (MUF) is high enough to support 28 MHz propagation between your station and western Europe?

What usually happens to radio waves with frequencies below the maximum usable frequency (MUF) when they are sent into the ionosphere?

At what point in the solar cycle does the 20-metre band usually support worldwide propagation during daylight hours?

If we transmit a signal, the frequency of which is so high we no longer receive a reflection from the ionosphere, the signal frequency is above the:

Communication on the 80 metre band is generally most difficult during:

The optimum working frequency provides the best long range HF communication. Compared with the maximum usable frequency (MUF), it is usually:

During summer daytime, which bands are the most difficult for communications beyond ground wave?

Which ionospheric region most affects sky-wave propagation on the 6 metre band?

What effect does tropospheric bending have on 2-metre radio waves?

What causes tropospheric ducting of radio waves?

What is a sporadic-E condition?

That portion of the radiation kept close to the earth's surface due to bending in the atmosphere is called the:

On which amateur frequency band is the extended-distance propagation effect of sporadic-E most often observed?

In the northern hemisphere, in which direction should a directional antenna be pointed to take maximum advantage of auroral propagation?

Where in the ionosphere does auroral activity occur?

Which emission modes are best for auroral propagation?

Excluding enhanced propagation modes, what is the approximate range of normal VHF tropospheric propagation?

What effect is responsible for propagating a VHF signal over 800 km (500 miles)?

What kind of propagation would best be used by two stations within each other's skip zone on a certain frequency?

If you receive a weak, distorted signal from a distance, and close to the maximum usable frequency, what type of propagation is probably occurring?

What is a characteristic of HF scatter signals?

What makes HF scatter signals often sound distorted?

Why are HF scatter signals usually weak?

What type of radio-wave propagation allows a signal to be detected at a distance too far for groundwave propagation but too near for normal skywave propagation?

When does scatter propagation on the HF bands most often occur?

Which of the following is not a scatter mode?

Meteor scatter is most effective on what band?

Which of the following is not a scatter mode?

In which frequency range is meteor scatter most effective for extended-range communication?