[Boatanchors] 40M noise

[James Liles]

Hi Phil:
That 40 M noise is interesting.  I have a similar problem here and wonder if 
yours is the same.

On the 40M band from 7.1Mc to 8.4Mc there is a 1 second sweep that the noise 
blanker can't handle.  I have a spectrum analyzer capture of the data and 
looks to be spread spectrum behavior.  It is originating in a neighbors home 
but he is reluctant to let me bring a trace agent into the house --- He 
probably thinks I'm after his silverware.  If anyone has the same problem 
and mitigation, I'm interested.

Kindest regards Jim K9AXN

------------------------------ ORIGINAL MESSAGE --------------------------

Message: 7
Date: Thu, 22 Mar 2012 18:09:00 +0000
From: Phil <ko6bb1 at gmail.com>
Subject: Re: [Boatanchors] Grounds, thanks all
To: Glenn Little WB4UIV <glennmaillist at bellsouth.net>
Cc: Boatanchor List <boatanchors at mailman.qth.net>
Message-ID: <4F6B6ABC.2080702 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi Glenn et al,
Thanks for your reply,  Actually, the "safety ground" was taken care of
before I moved in, that is, the 10 foot galvanized rod at the service
entrance.   As I use a "balanced antenna" (dipole) for transmitting the
RF ground is 'probably' not of as much importance, but that is debatable
too.

The PRIMARY reason for all the work I've put into grounding  is to
reduce the local noise that I have to put up with here.  All sorts of
strange noises, from sweeping multiple carriers (probably dozens to
hundreds of switching power supplies in the park), plain old "hash" like
you get from sparking motors, certain types of lights, etc as well as
one VERY WEIRD WIDEBAND QRM.  On 770 KHz (+- perhaps 50KHz), it makes a
strong "Sshh, Sshhh, Sshhh" noise at ~1sec intervals.  On 40M (and
elsewhere) there is a related noise, same cycle, that is just the
opposite.  That is, when if OFF on 770, it's there on 40M.   NONE of
this noise comes from anything in my own home as I've shut everything
down, including the utilities, (and the router and DSL modem which runs
on the station battery) and the noise doesn't abate one iota.   That
770KHz/40M noise is intermittent, not always present, but a big pest
when it's there.

When I improved the ground system here,  nearly all of the local noise
problems dropped greatly.  Thinking on the problem my suspicion is that
since all the grounds here are tied together AND tied to the mains
service ground, I've greatly improved the mains ground and thus any
noise that is radiated from my own home wiring .  Walking outside with a
portable radio certainly shows less noise around my home now  than
around the neighboring ones.  I only checked the ones on either side of
me as they know me and my "radio quirks".  If I were to walk around the
other places somebody would probably spot me and complain that there was
a "prowler" messing around.

I thank all who replied with ides.  Brian from VK land said "fix the
QRM".  NOT an easy task in this environment.   This is primarily a 55
and older senior park, but there are quite a few younger ones who
inherited their homes.  Some of them are "very suspicious looking
characters", and this being California, I wouldn't be a bit surprised if
they had "GROW LIGHTS" in their homes.  Grow lights are very well known
for the noise they generate. . .  You prowl around the homes of some
folks who have them and they just might carry you away "feet first".  If
you're unfamiliar with the term, just Google "Grow Lights".

Some nice tips here on using copper flashing etc.  But my first post was
concerning aluminum wire as my budget is so tight.  Certainly can't
afford copper flashing at this time :)

73 de Phil,  KO6BB
http://ko6bb1.multiply.com/ (OTR Blog)
http://www.qsl.net/ko6bb/  (Web Page)