You could try pointing out to the power company that you are detecting
insulators that are in the process of failing. They should be
interested in finding and replacing insulators that may cause them
problems in the future. They may also be interested if you point out
that each insulator that is causing noise like that is wasting power...
a small amount per insulator, but it adds up when there are hundreds or
thousands of them.
Since you say that the noise is better when it rains there are two
possible explanations. First, the insulator surfaces are cracked or
have arc damage, in this case the rain is filling the gaps and causing a
steady current instead of arcing. These should be replaced. The other
is that the insulators are dirty. In this case the arcing is between
gaps in the contamination, when it rains the gaps are bridged or the
contamination is washed off for a while, once the surface dries the
noise starts again. Power washing can remove contamination without
shutting off the line, but must be repeated regularly if you are in a
marine or heavy industrial area that contaminates them quickly. I have
also seen some surface treatments that can help prevent surface
contamination, but not sure how widely these are available.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> -----Original Message-----
> From: rfi-bounces@contesting.com [mailto:rfi-bounces@contesting.com]
On
> Behalf Of Simon Martin
> Sent: Monday, July 19, 2004 06:31
> To: rfi@contesting.com
> Subject: [RFI] Power Line Noise in Indonesia
>
> I am getting rather desperate to limit some of the interference
problems I
> am suffering, would really appreciate any useful advice:
>
> I have suffered severe power line noise for some time in my current
> location in Indonesia - I live in a built up area with interference
from
> multiple directions. Currently this means I can use bands from 17m and
up
> with little interference, but from 20m down I suffer terribly with
solid
> S7-S9 of power line noise, briefly disappearing during rain storms. I
have
> turned off the mains power and hooked the radio up to a battery but
the
> noise is still there so it is not coming from any appliance/s within
the
> house.
>
> Contacting the local power utility is useless, their concern is to get
> electricity to people not to sort out some hams interference problems,
so
> unfortunately sorting the problem at source is a non starter. I have
given
> up being able to work on 40m but would like to try and limit the
problem
> on
> 20m.
>
> Presently I use a 2 element yagi with insulated elements as a transmit
> antenna for 20m with an horizontal delta loop fed with 300 ohm
windowline
> as a receive antenna (this still receives solid S6 of noise) - the
yagi is
> fed with RG58 via a coaxial choke at the feedpoint and is grounded at
the
> entry to the shack.
>
> I have tried an MFJ1025 with noise sensing antenna but due to the
> intereference arriving from multiple directions have not had much
success,
> I have tried DSP in various forms such as external DSP speakers, DSP
on
> the
> radio, and also various software packages with the radio linked to the
> computer. None have provided very much relief
>
> I am aware that I will probably not be able to cure the problem unless
I
> can get to the source but am interested in any advice that might make
life
> easier, particularly on 20m. Moving to the countryside does not appear
as
> much of an option for me at the moment.
>
> Regards,
> Simon
> YB3ASD
> M0GOT
>
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