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2007 News Releases




ACMA Measures BPL Emissions at Mt Beauty

Date : 27 / 02 / 2007
Author : Phil Wait - VK2DKN

The Australian Communications and Media Authority (ACMA) performed background noise and emission measurements at the Mt Beauty BPL trial in Victoria, over the 20th-21st February. The measurements were in response to an interference complaint lodged with ACMA by Ian Paul VK3LJJ.

Gary Smith- Manager BPL Projects Team Regulation and Compliance Branch, and Colin Payne - Regulation and Compliance Branch Melbourne, represented ACMA. Yoram Apter - Project Manager BPL, represented SP-Ausnet, and WIA Director Phil Wait VK2DKN represented the WIA.

Background noise measurements were performed in various locations around the township of Mt Beauty, following deactivation of the BPL equipment by the service provider SP-Ausnet. BPL emissions and the effectiveness of notching the BPL signal in amateur bands were measured after system re-activation.

As expected high level BPL emission was measured in the trial area. The maximum notch depth measured within amateur bands was about 35dB. Background noise was higher than expected, highlighting the need for a series of noise measurements over many days to accurately determine typical background noise levels at any location.

Observations of BPL emissions received on Ian Paul's amateur transceiver and G5RV antenna were recorded by Phil Wait. Those observations confirm that, in the vicinity of Ian Paul's QTH, SP-Ausnet has notched all affected HF amateur bands except for 10 metres. However due to the higher than expected level of background noise on all amateur bands at the time of the observation, notch depth could not be adequately determined.

SP-Ausnet demonstrated new network control software that allows remote notching of frequencies or bands of frequencies, in any segment of their trial BPL network, from an office anywhere. It now appears relatively easy for SP-Ausnet to quickly notch amateur band frequencies in response to an interference complaint from an amateur.

As the maximum notch depth was measured at about 35dB, the WIA is of the opinion that both software and hardware notching will be required to adequately protect amateur radio operation from substantial interference from BPL emission, and that should be the focus of further development by BPL equipment manufacturers.

This measurement event also provided an ideal opportunity to compare real-world data from ACMA's measuring equipment and the FSM technique developed by Owen Duffy VK1OD and Ed Hare W1RFI. We were able to demonstrate close agreement between the two measurement systems, thus confirming our confidence in the FSM measuring technique and our own FSM measurement Jump-kit.

The WIA has now attended ACMA measurement events at Mt Nelson (TAS) and Mt Beauty (VIC) BPL trials. It is apparent that all stakeholders involved in BPL trials are now taking interference complaints from radio amateurs very seriously, and are making changes to their BPL technology and systems to improve the outcome for radio amateurs.

We would like to thank ACMA for their invitation to attend these measurement events, and for their constructive working relationship with the WIA.

Phil Wait

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