trắc nghiệm GMDSS lan truyen song dien tu

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One of the guidelines when choosing an High Frequency (HF) band for a specific
range, is
the greater the distance, the lower the required band
use a lower band by day
to have the antenna as high as possible
use a higher band by day
A
Line-of-sight propagation would mainly involve
communications on HF
communications on MF
Navtex communications
SART, EPIRB, Inmarsat communications
A
Ground wave propagation is an important feature of communications on
1.6 GHz
Ch.16 VHF
8291 kHz

2182 kHz
A
The main path of propagation for an 8 MHz radio frequency is
sky wave
direct wave (line of sight)
ground wave
troposcatter
A
The propagation path used by HF signals, from the SSB radio, to achieve long-range
communications, is
direct wave (line of sight)
relay wave
sky wave
ground wave
A
The main propagation path for an MF radio frequency is
space wave
sky wave
ground wave
direct wave (line of sight)
A
The propagation path for signals from a VHF radio, under normal atmospheric
conditions, would be
relay wave
ground wave
sky wave
direct wave (line of sight)
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Communications through the Inmarsat system are by

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combination of ground wave and sky wave
sky wave
space wave
ground wave
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The communications most affected by antenna height are
VHF
HF
satellite
MF
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Sky wave propagation is an important feature of H24 communication on

2187.5 kHz
Ch. 70 VHF
8414.5 kHz
121.5 MHz
A
When choosing an HF band for a specific communication, one of the guidelines is
that ducting can increase the range
to use a higher frequency band by day
that the range of 2 MHz transmission is greater by day
the greater the distance required, use a lower frequency band
A
The propagation path taken by a radio signal on VHF Ch.16 is
inverted wave
ground wave
sky wave
direct wave (line of sight)
A
The propagation path used by Inmarsat equipment is
relay wave
ground wave
sky wave
direct wave (line of sight)
A
The propagation path for MF NAVTEX signals during daylight is
relay wave
sky wave
ground wave
direct wave (line of sight)
A
The propagation path used by satellite EPIRB equipment is

direct wave (line of sight)
ground wave
sky wave
relay wave


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