[RFI] RFI all over the band

David Robbins K1TTT k1ttt at arrl.net
Sun Oct 1 07:42:02 EDT 2006

Power line noise that comes and goes with rain is likely caused by bad
insulators.  When the insulator is dry it is arcing and making noise, when
it gets wet the water fills the gap and current flows smoothly without

A government owned utility may be tough to deal with.  But I can think of
couple possibilities.  First, convince them that this type of noise is an
indication that an insulator is about to fail, and replacing it soon will
prevent greater damage and overtime pay when it likely fails during
non-working hours.  Or you could also convince them that it is a sign of
high leakage currents resulting in higher losses and wasted power.  You can
also try to turn other agencies against them, if the noise is interfering
with broadcast radio or tv stations you may be able to get them to put
pressure on the power authority to fix it.  Also check out police and fire
frequencies to see if it interferes with them in the area.

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net

> -----Original Message-----
> From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
> Behalf Of Ramakrishnan Muthukrishnan
> Sent: Saturday, September 30, 2006 16:09
> To: rfi at contesting.com
> Subject: [RFI] RFI all over the band
> Hi,
> I am Ramakrishnan, VU3RDD from Bangalore, India. For the past two
> months, I am experiencing unprecedented amount of RFI all over the
> amateur radio bands 40m, 20m till 10m at S9+10db level. I haven't
> checked upwards in the frequency. Virtually nothing can be recieved.
> It's also there in the broadcast bands as well.
> I live in a very densely populated area full of apartments. I am also
> in an apartment. To rule out any problems inside my house and also
> inside our apartment, I selectively switched off/on all the individual
> circuits including the lift (elevator) without any success. i.e. RFI
> didn't reduce at all. After reading some available material on the
> various webpages, I started roaming around our building and the area
> near the circuit breaker box is kept, with a battery operated AM radio
> tuned to a shortwave frequency where no station exist. I see that
> noise is strong almost everywhere inside our small compound wall, but
> I haven't found any specific source yet.
> Today it rained a bit and to my surprise I found that the noise level
> has reduced quite a lot from the S9+10 db that I was seeing. But once
> the rained stopped and water drained off, RFI is back to its usual
> S9+10 dB.
> I am completely clueless on how  to find the source. I do not have a
> VHF/UHF AM equipment or DF antenna yet. Many webpages suggest using
> such equipment to locate the source. The power company here
> (controleld by the Govt) is not very helpful either. Infact I had
> already reported to them about the problem and no one turned up. This
> is usual practice in this part of the world.
> I would appreciate any help from experienced members of this forum. I
> think the rain was a good source of clue, but don't know how to
> proceed further.
> Thanks
> 73
> --
>   Ramakrishnan - VU3RDD
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