TD 90227GB
2006-09-18/ Ver. C
System Installation
On Site Paging System
16
An essential difference between the old 800 system and the OSP systems is that the 800
system must be grounded at only one point if the units are dc coupled. This must be
considered when planning a combined system installation.
T850
U952
T840
Figure 17. An example of an installation that cannot function due to grounding.
Both transmitters are mounted on grounded masts. Ground currents cause interference in
the current loop between T840LM and T850.
There are two solutions for this:
• Install antenna transformer MAT-50 on transmitter T850.
• Install modem T838 between T840LM and T850.