Slide 16 INNOVATIVE LOCALIZER ANTENNA INSTALLATION To investigate sea spray dump protection measures we undertook tests upon a single antenna element to determine what parts were most sensitive to the presence of salt water. Slide 14 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Protection from Sea Spray Dump: This Picture shows the proximity of the new Localizer antenna to the Ocean Slide 15 INNOVATIVE LOCALIZER ANTENNA INSTALLATION This picture shows a moderate sea spray dump over the new Localizer Antenna. We were then confident that we would achieve a coverage not less than that previously obtained with the down the bank antenna. Slide 12 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Slide 13 Whilst a low mounted antenna system appeared to potentially match the coverage of the previous down the bank system it was decided to add some margin by using a 14 element array together with placing the equipment room underground immediately below the antenna array so as to minimize cable loss. This suggested a suitable minimum height to mount the antenna array. This shows the 10dB reduction occurs around 0.55m height. A graph of the relative signal level versus height for a surface mounted array is displayed in the next plot. Slide 10 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Slide 11 Localizer coverage The difference in signal strength in the user airspace between a down the bank mounted 8 element antenna and a normal height surface mounted 8 element antenna is approximately 10dB. The following plot shows that matching was not going to be a problem and was best at around 600mm height. Slide 9 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Antenna Height Issues: To check the effect upon the antenna element matching a single antenna element was mounted on a variable height support and the Input feed VSWR measured at various heights. At this distance the antenna could be subjected to jet blast wind speeds greater than its design limit. Slide 8 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Thirdly Protection from Jet Blast: The new Localizer antenna would be only 53 metres from the runway starter extension. With the new Localizer antenna located closer to the sea the problem of spray dump is much greater. Sea spray had already been a cause of shutdown with the previous 8 Element Localizer antenna. Issues we faced in accomplishing this were threefold Slide 7 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Secondly - Protection from Sea Spray: During Southerly Storm weather conditions a significant quantity of sea spray is dumped over and beyond the wave trap at the southern end of the runway. This restriction could impact adversely upon both the Localizer antenna element matching as well as the achieved Localizer coverage. Slide 6 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Firstly - Antenna Height : Obstruction Clearance Surface requirements limited the total available height for the new Localizer antenna to no greater than one metre. There was no possibility of locating a Localizer antenna down the bank into the wave trap and so we began consideration of locating a reduced height antenna on the surface of and at the end of the RESA adjacent to the wave trap. Slide 4 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Slide 5 In order to provide for a runway end safety area at the Southern end of the runway the runway strip needed to be extended over an existing roadway and up to the edge of an existing wave trap. The next photo shows the previous antenna in this configuration. This arrangement also provided protection for the antenna system from direct jet blast. The localizers associated with those ILSs had their 8 element antenna systems mounted down the bank at each end of the runway strip so as to avoid penetrating Obstruction Clearance Surfaces. Slide 2 INNOVATIVE LOCALIZER ANTENNA INSTALLATION Slide 3 Inline ILS systems serving both approaches were first installed some 30 years ago. The next photograph illustrates this layout. The south end of the runway finishes adjacent to the open sea of Cooks Strait whilst the Northern end finishes adjacent to Wellington harbour. INNOVATIVE LOCALIZER ANTENNA INSTALLATION Wellington International Airport runway is built on a narrow neck of land.
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