The Coastal Impacts Unit for the Queensland Government sits within the Department of Science, Information Technology and Innovation (DSITI).
One function of the Coastal Impacts Unit since 2013 has been to measure sea levels and tides in the Torres Strait, the body of water between Queensland and Papua New Guinea.
A long-term project of the Coastal Impacts Unit has been to maintain measurement of permanent sites in the Torres Strait including Ugar (or Stephens Islet), the subject of this case study.
The CIU operate five tide gauges on islands around the Torres Strait. At each measurement site, there are two sensors which provide data correlation plus redundancy in case of equipment failure. Solar power has also been installed capable of providing one week of back up battery and capable of charging the system with one full day of solar activity. Recorded data is stored in a data logger recording multiple input every minute – it is capable of holding the data for minimum nine months. The data from the logger is transmitted to DSITI via a 3G mobile data connection.
All sites are working well with the exception of one – Ugar. There is a hill between the Instrumentation and the closest mobile tower, located 30 km away on Yorke Island in the South West, which occasionally blocks the RF signal.
Upon initial installation, standard equipment was utilised. Poor mobile data problems were detected causing intermittent 3G data service coverage and irregular information downloads from the gauge. In response, further equipment including a satellite modem, was added.
From installation in November 2013 until the second maintenance visit in November 2015, Ugar site information had to be manually downloaded and then manually entered into a database. Unfortunately there was no appropriate solution available for extending the mobile signal.
After the maintenance visit in November 2015 the Coastal Impacts Unit decided to investigate whether a mobile repeater solution could increase the connection availability at the Ugar site. The aim was to increase the Mobile signal and data throughput for a 500 m radius around the repeater enabling consistent connection with the tide gauge.
The Cel-Fi PRO repeater was reviewed but it was not suitable due to the separation required between the Network and the Coverage Unit.
The Coastal Impacts Unit were interested in whether the new Cel-Fi GO would be an appropriate solution for this site and achieve the boost required to ensure 100% data recording. As a result of discussions with Powertec it was agreed to test this device for this specific situation.
Cel-Fi GO is a one-box solution with a separation requirement of approx 1 metre between the input and output antennas. For the installation, they mounted a 6.5 metre pole with an 8.1 dBi omnidirectional antenna at the top and LMR400 cable down to the instrumentation box.
“The good news is that the site has connected the past few mornings since installation, so the connection is enough for us to get our data.”
The Cel-Fi GO will be the subject to continued testing at this site and we will be excited to monitor ongoing results
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