User's Manual

CellTrackIT user manual Version 0.9 Page 10
reduced (obstructions). However, this could be compensated for, as the
reduced range will include more apartments and more transponders than a
less dense site.
Landscaping. Trees and shrubs when blocking the line of sight to the
transponder can cause scattering of radio signals and therefore must be
included when planning the network. The terrain plays an important part in
determining how many repeaters are needed. A reduced RF range can result
if hills and valleys cause large variations in the building heights or if hills
obscure the line of sight, resulting in an increased ratio of repeaters to
transponders.
RF Interference. Very strong external radio signals nearby, operating at the
same or near same frequencies as the CellTrackIT system can create
interference that will reduce the range to the Transponder and if present will
need to be compensated for. Potential RF interference sources are Cellular
telephone base stations at a distance of less than 800ft and Paging towers at
a distance of less than 5000ft, or other 900Mhz ISM band AMR systems that
are located close to the repeaters on the site. Many radio systems operate at
peak output during the daylight hours with diminished signal trafficking during
the night. Planning must take into account the operational hours of these
various radio systems to ensure that the system is designed for maximum
efficiency with the minimum number of repeaters.
RF self interference The minimum antenna to CellTrackIT or PC distance
should be greater than 1m. The minimum line of sight distance, repeater to
Node should be 45m.
Cable length
It should be noted that longer RF cable runs will cause the range to be
reduced, the node therefore will typically be used with a longer cable to site
the PC and in such cases will have reduced range.
Aesthetics. This is one factor that may require some negotiating with the
apartment owner or supervisor. In most cases the placing of antennas on
roofs or under eaves will not be an issue. However, it pays to first ask or to
explain the extent of change to the outward appearance of the building(s).
The supervisor or owner will definitely appreciate the consideration. Placing
the antenna inside buildings will reduce first and second tier ranges, as roof
and inner walls will attenuate radio signal.
Antenna