I would check your neighbors and ask them if they have a plasma TV....I
experience that same kind of noise when my next door neighbors turn theirs
on, which I can see from the window of the shack.
----- Original Message -----
From: "Ed Richardson" <Ed_richardson@shaw.ca>
To: <rfi@contesting.com>
Sent: Sunday, October 24, 2010 7:27 PM
Subject: [RFI] Wideband Noise
> Borrowed a Rohde & Schwarz FSH8 handheld spectrum/network analyzer for
> the weekend to try and track down a nagging issue that has been
> bothering me on 160-40m.
>
> The noise is wideband covering all 3 bands and takes the form of period
> rapid increases in noise level. On the Icom 7700 receiver it takes the
> form of background noise rising 3-4 S units in a seemingly random
> pattern and pulsing at a maximum rate of perhaps 10 Hz. At other times
> it may be several seconds before a series of spikes arrives. The desire
> signals all remain the same level and weaker ones just get masked by the
> noise.
>
> On the spectrum analyzer I confirm the ambient noise peaking 12-20 dB
> across the 1.6 = 11 MHz range. It almost looks like the signal is some
> kind of wideband modulation.
>
> Walked the neighborhood over a mile in all directions. (Boy you get some
> strange looks carrying a spectrum analyzer down the street). The effect
> was found everywhere, some spots stronger than others but no clear
> source.
>
> Inserted bandpass filters in for each of the ham bands and the noise
> peaks remain in band.
>
> The only clue I have is this only happens after dark. 7 days a week. My
> first thought was the sodium street lights but I visited one that is
> failing (turning off and On) and the noise was no worse.
>
> Anyone have any suggestions?
>
> Ed
> VE4EAR
>
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