Hello, Brad, et al,
This sure looks like unfortunate news for our Australian fellows.
It is about 20 dB WORSE than the limits in the US FCC Part 15 regulations
(US permits 30 uV/m at 30 meters on HF). To take the worst-case HF
example from the LIPD devices:
RESULTS
Frequency = 3.7 MHz
Total transmit power = -21.24 dBm
Transmit antenna gain = 0 dBi
Receive antenna gain = 2.15 dBi
Distance to receiver = .03 km
Free-space pathloss = -13.35646 db
System loss (path loss +/- antenna gains) = -11.20646 dB
Total average E field = 500.55 uV/m
Receive system Noise Figure = 24 dB(includes external noise)
Calculated receive system sensitivity in 2500 Hz bandwidth = -116.0206
dBm
Received signal in receiver bandwidth = -32.44646 dBm
Received signal in receiver bandwidth = S9 + 40.55354 dB
Receive system noise floor increase in dB = 83.57413 dB
The limits for Australian "Part 15" devices won't impact US Amateur Radio, but some of the manufacturers may cite the Australian rules as being acceptable for what the limits should be. The US Part 15 limits result in the following on 3.5 MHz:
Frequency = 3.5 MHz
Receive antenna gain dBi = 2.15
Field strength uV/m = 30
Receive antenna at 30 meters distance = -56.4012 dBm (This
is 16.5988 dB over S9 )
Bears watching. If Andrew knows who my EMC/EMI/breakthrough counterpart
is in Australia, I can share my work with him or her to help them deal
with this.
73 from ARRL HQ,
Ed Hare, W1RFI
ARRL Lab
225 Main St
Newington, CT 06111
860-594-0318
w1rfi@arrl.org
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Thanks for the analysis.
Ed - W1RFI -- I believe that the following is significant information
concerning interference with Amateur bands by outside devices such as
the US Part 15 devices. I have looked at the www site and found
it interesting reading.
I understand that Australia will not allow some US Part 15 devices to
be imported without additional filters to trap out certain spectrum
problems. These same devices are apparently OK in the US.
I can't be specific, but this story has been around the industry for some
time.
I will try to locate a specific reference.
This LIPD story seems to be specific to 70 CM in VK, but the other devices also seems to affect other bands as well.
I believe the VK experience will be useful in our Part 15 device discussions and proposals to FCC.
73, Brad Wyatt K6WR