Comparison of effects of various roofing materials on navaids transmission distance

ABSTRACT: The occurrence of interference that causes partial loss of intelligence in air
navigation signal is largely dependent on total environment around radio navigation aid systems
(navaids). This paper compares the effect that selected roofing materials have on Navaids
transmission distance. To achieve this, a transmitter, a receiver and a computer to measure
signal level transmitted through roofing materials at a frequency of 9.4GHz were used. The study
considered effects of decra, iron, steel, aluminum, plastic and clay materials on navaids
transmission distance. The study found that effects of roofing materials on transmission distance
varied depending on the type of selected roofing material. Signals via plastic materials
decreased with distance as those via aluminum increased with distance. However the overall
effect of roofing materials on transmission distance was not significant since the received signal
was within the recommended strength. More so, the materials had path loss exponent factors of
between 3.0 to 3.7 which meant that, the rate at which the signal was propagated through these
structures, was significantly slower than in free space where exponent factor is 2. It is
recommended that studies be directed in conducting experiments in open fields and factoring in
sources of variability arising from the environment so as to relate to the actual scenario of flight
navigation.
KEYWORDS: Roofing Materials, Navaids, Transmission, Distance