PlantLinc
PLR5000 User’s Guide
P/N 161-09888-001
DATA-LINC
Group
21
PLR5000 Location
Placement of your PLR5000 is likely to have a significant impact on its performance. In general, the rule of
thumb with the PLR5000 is that the higher the placement of the antenna, the better the communication. In
practice, you should also place the radio modem itself away from computers, telephones, answering
machines, and other similar equipment. A 6-foot RS232 cable will usually provide ample room for placement
away from other equipment. To improve the data link, Data-Linc Group offers directional and omni
directional antennas with cable lengths ranging from 10 to 200 feet.
When using an external antenna, placement of that antenna is critical to a solid data link. Other antennas in
close proximity are a potential source of interference. It is also possible that slight adjustments in antenna
placement (as little as 2 feet) will solve noise problems. In extreme cases, such as when the radio modem is
located close to pager or cellular telephone transmission towers, Data-Linc Group offers a band pass filter to
reduce the out of band noise.
Using an External Antenna
In certain circumstances, it may be desirable to extend the range of the PLR5000 radio modem by using an
external antenna in place of the standard whip antenna. The radio modem is equipped with a standard SMA
external jack. This allows the use of external omni directional or yagi antennas. These are part of kits
provided by Data-Linc Group and include coax cable. These antennas allow versatility in the PLR5000’s
deployment, extending its range and allowing it to get around obstructions.
The use of an external antenna may radically improve the results obtained with PLR5000 radio modems. It is
imperative to obtain line of sight with the antennas, and changes in placement height of as few as a couple of
feet may make the difference between no link and one that is solid and reliable.
If external directional antennas are used, FCC regulations concerning effective radiated power limitations
must be followed.
Caution:
Any antenna placed outdoors must be properly grounded. It is required by FCC regulations that
qualified personnel experienced in antenna installation and familiar with local codes and regulations
complete the antenna installation. It is also required by FCC regulations that only approved antennas be
used. Use extreme caution when installing antennas and follow all instructions included with the
antennas.
The use of an external antenna subjects the radio modem to greater exposure to direct lightning strikes. It is
strongly recommended that a lightning arrestor be used on all outdoor antenna installations.
Long RS232 cable runs should also be avoided in areas with increased lightning activity or static electricity
unless they are properly isolated from the radio modem. Nearby lightning strikes or elevated levels of static
electricity may lead to voltage spikes on the line, causing failure in the radio modem’s RS232 interface. It is
also recommended that the RS232 data cable not be located near high voltage power lines as this can cause
interference in data communications, damage the PLR5000 as well as an increase in risk of personal injury.