Bureau of Meteorology impacted by internet service providers' move to wireless frequency
By Jonathan Hair, Wed 16 May 2018
The Bureau of Meteorology's (BOM) ability to accurately measure the weather could be affected by plans to move some wireless internet service providers onto its radar frequency.
The BOM has warned that changes to the radio frequency it operates on, the 5.6GHz band, could cause problems with its radar system's range, resolution, and measurement accuracy.
Dr Konstanty Bialkowski, an expert on radar systems from the University of Queensland, said the 5.6GHz was good at interactions with water content.
"In terms of reflectivity and water absorption, and because of that it's able to detect rain particles and rain and things like that," he said.
The new 5G mobile network needs a frequency band to operate on, and the Federal Government is planning to auction off parts of the 3.6GHz band for it in October.
But already using that band are a number of wireless internet service providers, which need a new home.
The Australian Communications and Media Authority (ACMA) has proposed moving them to the 5.6GHz band, which is already used by the BOM.
In a statement the BOM said it was working with ACMA to resolve any potential issues of interference.
Dr Bialkowski said interference came into play because of "leakage".
"The issue is that signals, when they operate in a band, also have a leakage in an adjacent spectrum," he said.
"The leakage occurs because when we create a signal, it actually has a very wide spectrum, and we use filters to limit the out of band signals which occur.
"You can never get that down to zero, it always will exist.
"That signal, although it is not that strong compared to a signal of interest, is actually quite strong compared to the level of signal expected from far away rain particles."
Dr Bialkowski said it could be as extreme as storms appearing on the radar, even if they did not exist.
"Effectively it could look like a false return, so maybe rain occurring where the operator is actually using their antenna," he said.
"And it could be a very strong one, which would give a very false impression that some sort of storm was occurring where in reality nothing was actually occurring there at all."
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