T3B Tropospheric ducting or bending; amateur
satellite and EME
operations
T3B01
@T3A02
Ducting
occurs in which region of the atmosphere?
A. F2
B. Ecosphere
C. Troposphere
D. Stratosphere
T3B02
@T3A03
What
effect does tropospheric bending have on 2-meter radio waves?
A. It lets you contact stations farther away
B. It causes them to travel shorter distances
C. It garbles the signal
D. It reverses the sideband of the signal
T3B03
@T3A04
What
causes tropospheric ducting of radio waves?
A. A very low pressure area
B. An aurora to the north
C. Lightning between the transmitting and
receiving stations
D. A temperature inversion
T3B04
@T3A05
What
causes VHF radio waves to be propagated several hundred miles
over
oceans?
A. A polar air mass
B. A widespread temperature inversion
C. An overcast of cirriform clouds
D. A high-pressure zone
T3B05
@T3A06
In which
of the following frequency ranges does tropospheric ducting
most
often occur?
A. UHF
B. MF
C. HF
D. VLF
T3B06
@T3A08
What
weather condition may cause tropospheric ducting?
A. A stable high-pressure system
B. An unstable low-pressure system
C. A series of low-pressure waves
D. Periods of heavy rainfall
T3B07
@T3A11
How
does the signal loss for a given path through the troposphere vary
with
frequency?
A. There is no relationship
B. The path loss decreases as the frequency
increases
C. The path loss increases as the frequency
increases
D. There is no path loss at all
T3B08
@T3C05
Why are
high-gain antennas normally used for EME (moonbounce)
communications?
A. To reduce the scattering of the reflected
signal as it returns to
Earth
B. To overcome the extreme path losses of this
mode
C. To reduce the effects of polarization
changes in the received
signal
D. To overcome the high levels of solar noise
at the receiver
T3B09
@T3C07
Which
of the following antenna systems would be the best choice for an
EME
(moonbounce) station?
A. A single dipole antenna
B. An isotropic antenna
C. A ground-plane antenna
D. A high-gain array of Yagi antennas
T3B10
@T3C10
When is
it necessary to use a higher transmitter power level when
conducting
satellite communications?
A. When the satellite is at its perigee
B. When the satellite is low to the horizon
C. When the satellite is fully illuminated by
the sun
D. When the satellite is near directly overhead
T3B11
@T3C11
Which
of the following conditions must be met before two stations can
conduct
real-time communications through a satellite?
A. Both stations must use circularly polarized
antennas
B. The satellite must be illuminated by the sun
during the
communications
C. The satellite must be in view of both
stations simultaneously
D. Both stations must use high-gain antenna
systems