Trimble Inc. 7112-900IP 사용자 설명서
20
Note – For TC900 antennas, this means keeping the antenna element vertical
and at the same elevation as the transmitting antenna. Otherwise, it may be
better to use an antenna with less gain.
and at the same elevation as the transmitting antenna. Otherwise, it may be
better to use an antenna with less gain.
A.2
Point-To-Point Link
Many factors can reduce the reliability of a TC900 link: multipath fading,
shadowing, and interference. Multipath fading results when multiple reflected
copies of the transmitted waveform destructively interfere at the receive antenna.
However, this type of fading is usually localized to areas just a few inches across,
so moving an antenna just a few inches can sometimes overcome it.
shadowing, and interference. Multipath fading results when multiple reflected
copies of the transmitted waveform destructively interfere at the receive antenna.
However, this type of fading is usually localized to areas just a few inches across,
so moving an antenna just a few inches can sometimes overcome it.
Shadowing results when the link loses line-of-sight (LOS) due to an obstruction
such as a building, hill or trees. Sometimes it is possible to receive a signal
without LOS because radio waves may diffract around some obstructions or
travel through others. The only way to know where a link will work is to try it.
such as a building, hill or trees. Sometimes it is possible to receive a signal
without LOS because radio waves may diffract around some obstructions or
travel through others. The only way to know where a link will work is to try it.
Interference is generally caused by other transmitters in the same frequency band.
The TC900 minimizes interference problems from other transmitters by utilizing
unique state-of-the-art spread spectrum, frequency-hopping radio technology.
The TC900 minimizes interference problems from other transmitters by utilizing
unique state-of-the-art spread spectrum, frequency-hopping radio technology.
Tip – Antenna height is the single most important factor that you can use to
increase link distance. Always place omnidirectional reference, repeater, and
rover antennas as high as possible above surrounding obstructions. Use hill tops
and antenna masts wherever practical.
increase link distance. Always place omnidirectional reference, repeater, and
rover antennas as high as possible above surrounding obstructions. Use hill tops
and antenna masts wherever practical.