Hi Tim,
First, let me say that I was only an observer to all testing. I neither
selected any of the test equipment nor took any readings myself. I am not
part of the utility's BPL project team. I'm just the wireless
(2-way/paging/data) engineer for the utility who also has responsibility
for locating power line (arcing) noise meeting Part 15 requirements.
On the Amateur Radio side was the local radio club's technical committee
chair. He used a Hewlett Packard 8559B spectrum analyzer with a 30 dB
preamp and 2.5MHz HPF, FM (80-108 MHz) trap, TV Ch 3, ¼ wave trap. The
antenna was a homebrew bi-conical horizontally polarized with a relatively
flat response from about 13 MHz to over 100 MHz.
On the BPL team's side they used an Agilent spectrum analyzer (E4411B?)
using a loop antenna.
Before the testing, I had provided information to the BPL crew about QP
receivers and also about loop antennas. The utility's BPL consultant
selected the loop antenna and analyzer for the utility to rent for
testing.
73, de ed -K0iL
-----Original Message-----
From: Tim Groat
I'm curious if you measured the "noise pulses" with a quasi-peak receiver
or spectrum analyzer. That is what the FCC specifies for Part 15 devices at
HF. The QP detector has a fast-attack, slow-decay response (1ms and 1 sec
time constants, respectively, if I recall correctly). It's intended to
represent the perceived severity of low duty cycle interference sources.
I have seen more than 30dB difference between the QP detector and average
signal levels. That often happens when a rectifier produces short,
high-amplitude transients at every AC line half-cycle.
73,
--Tim (KR0U)
At 12:00 PM 10/25/04 -0400, you wrote:
>There were noise pulses there that were about 40-60db above the noise
>floor, but they were very thin across the band so they didn't cause
>much interference.
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