Nautel NX5 AM, Руководство по предварительной установке

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NX5 PRE-INSTALLATION MANUAL RF OUTPUT REQUIREMENTS
VERSION 0.1 2015-08-01 PAGE 1.6.3
Bowl Type Bushings
Use bowl type bushing insulators to increase the surface tracking distance from the central conductor
to the grounded periphery or wall.
Insulator Breakdown/Damage
Insulator damage can occur during gas breakdown flashovers. When current flows across the surface of
an insulator, especially when it is coated with a conductive contaminant that is slightly damp, carbon
tracks can form. Once this occurs, the track provides a conductive path and reduces the effectiveness of
the insulator.
Pitting and erosion of the insulator may also occur. To reduce the possibility of tracking damage, clean
all insulator surfaces periodically, and use stress control techniques at the conductor/insulator junction.
Other Causes
Other causes of breakdowns may include improperly adjusted spark balls or the disruption of air gaps
by rain, snow, insects, birds, grass, or an accumulation of pollution (soot) on insulator surfaces.
Small Radius Conductors
Be careful when using small radius conductors to carry high RF voltages and currents. If the radius is
too small it may cause a local corona, which can lead to a breakdown.
Feedline Testing
Test the RF transmission system from the transmitter flange to the antenna before putting the
transmitter into service. This is very important, especially if you are re-using an existing site with a
previously installed feedline. Ensure that the entire system can tolerate the expected peak voltages of
normal operation, especially those occurring during modulation peaks, without breaking down.