Worksheet Module
A complete transmission
analysis is carried out in the Microwave Worksheet module. The data entry
forms are accessed by clicking on an equipment icon. The worksheet is calculated
and the results are displayed as the data entry proceeds.
Reliability Methods
Multipath propagation reliability
can be calculated using any of the following methods:
-
Vigants - Barnett (C factor,
climatic factor and terrain roughness). Terrain roughness is calculated
over any segment of the profile reference to sea level or to a least squares
fit of the terrain.
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ITU-R P.530-6 (path inclination,
grazing angle and geoclimatic factor). The grazing angle is calculated
by defining the dominant reflective plane on the profile)
-
ITU-R P.530-7 (path inclination
and geoclimatic factor)
-
KQ factor
-
KQ factor including terrain
roughness. The frequency and distance exponents can be set for specific
regional standards.
Propagation reliability can
be expressed as availability or unavailability using the following conventions.
-
Total time below level for the
worst month and annual basis.
-
Worst month unavailability and
severely errored seconds (SES) using the criteria that fades which last
longer than 10 consecutive seconds are considered as system unavailability.
The remaining time below level is considered as SES.
Diversity Improvement Systems
The following diversity
improvement calculations are provided for baseband switching and IF combining
systems.
-
Space diversity
-
Angle diversity
-
Frequency diversity for 1 for
1 and 1 for N systems
-
Hybrid diversity - a frequency
diversity system equipped with space diversity at one end.
Rain Attenuation
Outage due to high intensity
rain can be calculated using the Crane or ITU-R p.530 methods using any
of the following rain statistics files:
-
Crane rain regions
-
modified Crane rain regions
(1966)
-
ITU rain regions
-
Canadian data for 47 radiosonde
locations
Passive Repeaters
Passive repeater links can be
created using single/double rectangular reflectors or back to back antennas.
A path can have up to three passive repeaters of any type. Separate path
profiles are first created for each passive link and analyzed for clearance.
The profiles are then merged together in the Microwave Worksheet module
to form the complete passive design, including transmission and propagation
reliability analysis.
Templates
Data entry can be simplified
by loading the equipment parameters from another pathloss data file. Any
file can be used as a template.
Lookup Tables
Lookup tables can be created
for antennas, transmission lines, radios and TX channel assignments. Data
can be imported from antenna and radio data files into a lookup table or
directly into the worksheet.
VHF - UHF WORKSHEET MODULE
A separate worksheet is available
for applications in the VHF-UHF and cellular frequency ranges. The
data entry format is tailored for the typical equipment specifications
used in these applications.
Antenna gains in these frequency
ranges are usually specified in dBd (dB above a theoretical dipole) and
are mounted with a horizontal antenna boresight unlike microwave antennas
which provide for vertical alignment. The transmission analysis considers
the vertical and horizontal antennal angles using antenna data files.
The VHF-UHF Worksheet module
includes lookup tables for antennas, radios and transmission lines and
uses antenna data files. The template feature is also implemented for data
entry convenience.
Last Update: 08/05/99