User's Manual
22
SEL-FT50/SEL-FR12 Fault Transmitter and Receiver System Instruction Manual Date Code 20170317
System Installation
while a fade margin of 15 dB yields good radio performance for critical
communications links.
Site Survey. A line-of-sight path provides the most reliable transmission
in all cases. As the distance increases, the need for a clear path becomes more
critical in creating a reliable, available radio link. If you have a clear line-of-
sight to the other location without obstructions to the Fresnel zone (see Radio
Path on page 20) then a path study is generally not needed. Longer distances
may require a path study, a visual path inspection, and a spectrum analysis of
the area to give a good indication of how high the antenna needs to be and how
good the radio link will be.
Radio Interference. The SEL-FT50 shares frequency spectrum with other
services and FCC Part 15 (unlicensed) devices in ITU Region 2 (North,
Central, and South America). Error-free communication may not be
achievable in a given location and some level of interference should be
expected. For a given fault, the SEL-FT50 sends four consecutive messages.
This mitigates the effect of radio interference by increasing the odds that a
fault indication will be communicated successfully during situations with poor
channel conditions.
Physical Installation
Install the SEL-FT50 on a distribution line by using an industry-standard hot
stick.
Step 1. Use a hot stick to grasp the hook eye on the side of the
SEL-FT50, and place the device on the line so that the opening
hangs over the line.
Figure 17 Positioning the SEL-FT50
Step 2. Apply slight downward and sideways pressure until the device
is closed around the line.
The spring mechanism should be pushed in, so that it wraps
around the line.
Figure 18 SEL-FT50 Installation Position