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Re: Topband: 160m Noise Floor

To: <>
Subject: Re: Topband: 160m Noise Floor
From: "Gary Hinson" <>
Date: Thu, 2 Sep 2010 20:36:49 +1200
List-post: <">>
> My QTH is in a suburban neighborhood surrounded by other 
> houses. Manmade noise sources in the area are producing a 
> receive noise floor of S-9 across the entire 160m band.
> Does anyone have any suggestions on how to reduce the noise?

Move to the country  :-)

Use another band  :-)

Use a remote receiver in a better QTH  :-)

If none of those are an option, there are some practical things you can do
such as systematically hunt down and eliminate the noise sources - easy
enough in your own home, harder at the friendly neighbors and near
impossible for those you don't get along with.  Switchmode power supplies,
plasma and CRT TVs, WiFi routers and other PC & networking gear, even light
dimmers can cause horrendous QRM across HF.  Curing them is easy if you can
afford to replace them with better (properly designed and actuall
suppressed) models, trickier if you need to start messing around with
ferrits and bypass capacitors.

Arcing MV insulators on the local HV/MV grid are a classic problem radiating
cr*p up to several miles around along the power lines.  The power company
*should* help, but hams are generally not on their Christmas card lists.

"Broadband over power line" systems, both the area wide and in-house
versions, are a total nightmare.  WiFi is definitely the lesser of two
evils, while fiber optics or properly specified and installed twisted pair
or coax Ethernet are fine if you have the choice ... which you almost
certainly don't.  Maybe you can persuade your neighbours to turn their
systems off when they go to bed?

'Noise reduction' systems of various types will ameliorate the remaining
crud to some extent.  Phasing systems with active noise receiving antennas
get decent reports if you have the patience to setup, tune and phase them
right, but in a noisy urban environment with multiple sources and
directions, they are on a hiding to nothing.  Analog noise blankers make
things worse, on the whole, but decent DSP noise reduction software is
surprisingly good these days.

Narrow CW filters are great if you use CW or data modes.  

Last but definitely not least, the wetware filter between your ears can do
wonders with oodles of practice, perseverance and experience.  

73 GL
Gary  ZL2iFB

UR RST IS ... ... ..9 QSB QSB - hw? BK

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