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BPL interference - the battle continues
On Thursday 11 January 2007, Australian regulator ACMA undertook another
round of measurements at Conrad VK7HCK's QTH. Equipment was specially
flown in from Melbourne, with Conrad, Phil VK2DKN, Harvey VK7HK, Greg
VK7YAD and myself in attendance.
Measurements were taken using a flat-response loop antenna and also using
Conrad's quad and vertical antennas so a comparison could be made between
the calibrated professional antenna and tuned amateur antennas.
There was definite correlation between what Conrad was reporting using
the "S" signal strength scale and what was measured using the
test equipment on the same antenna.
ACMA took notch profile measurements which showed up to a 20dB notch depth
however this still resulted in about an S3-4 signal level being experienced
by Conrad within a notch.
As some background, Conrad put in a complaint of unacceptable levels of
interference from BPL emissions in November 2005 and then again in September
2006, and these have been the subject of an ongoing investigation by ACMA.
ACMA staff undertook initial measurements at Mt Nelson in November 2005,
June and July 2006. ACMA even detected emissions at the Quoin Ridge ITU
monitoring station which is 20km away back in November 2005, however that
is no longer the case, possibly due to the utilisation of wireless technology
for the BPL back-haul network.
Following Conrad's complaint of September 2006, ACMA compiled their measurement
results into a report which was released at the end of November 2006 and
reported signal levels ranging from 34.1 to 64dBuV/m across the HF amateur
bands.
This ACMA report substantiates the claims made by Conrad that the Aurora
Energy BPL system is causing interference and greatly reducing his ability
to operate licensed amateur radio equipment.
It was acknowledged during the measurement day, that Aurora has, through
notching and wireless backhaul, reduced the level of emissions over the
period of the trial.
Conrad has requested further reductions in emission levels including the
widening of notching in various bands and notching of the 10m band.
We await with interest the release of measurement results from this round
of testing.
Justin VK7TW
Source: Wireless
Institute of Australia
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