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[RFI] FOUND! - Looking for ideas about yet another noise source

To: rfi@contesting.com
Subject: [RFI] FOUND! - Looking for ideas about yet another noise source
From: "Christopher E. Brown" <cbrown@woods.net>
Date: Mon, 27 Jul 2009 00:51:24 -0500 (CDT)
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>

So, as some suggested it was static discharge, just _not_ on any of my 

I still have no idea where the apparent modulation on 20M comes in, I 
discounted it being an AGC artifact because multiple receivers by 
different makers, diff design and 15 year age diff) behaved the same.

I spent alot of time slowly driving around the area with a receiver 
connected to a 102" whip through a -30db pad, enough to eliminate all but 
the stronger pulses.  I found that more than 2 streets away it was gone, 
but strong on my street.  Checking both nearby subdivisions (I am in the 
corner of mine with an undeveloped area seperating me and 2 others), one 
had similar strength along the street closest to my home.  There is a long 
hill between this area and my house.

Driving along the street I happened to spot a copperweld longwire leaving 
one house running up the hill and decided to talk to the owner.

It was an SWL with a very nicely installed longwire, #12 copperweld 
running from an electric fence insulator on the house to a tree on-top the 
hill and a good 100 foot on the other side of the hill.  About 350 feet 
total, entire length well insulated.  He also was botherd by the same 
noise, but much worse than I, topped the scale on any band.

SWL had single insulated wire running from antenna to antenna port of 
radio, a good 350 feet of well insulated, totally ungrounded wire, the 
last couple of hundred feet running over the hill that almost always has 
at least 5mph breeze, generally more.

After talking to the SWL we popped the cover on the radio and found 
visable signs of arcing from the centerpin of the RCA inside of the rig to 
the chassis (antenna had been connected for about 2 years).

I helped him install a couple thick film 100k carbon resistors to chassis 
ground, and suggested he look into a antenna feed involving a rf 
transformer that DC grounds the antenna side of things to improve his 

For the time being though, we are both much happier, with the bleeders in 
place the +40 to +60 pops are gone, leaving more normal static levels.

The last 100 feet of the longwire that was arcing is about 500 feet from 
my vertical, coming down the back side of the hill.  Clear line of sight, 
running a 45 deg slope directly twards my home.

On Sat, 11 Jul 2009, Christopher E. Brown wrote:

> Attempting to track down a bothersome very intermittant noise and looking
> for some ideas.  Don't have a decent way to record it, but may need to set
> something up if I cannot make headway.
> Noise is pulse, appears on at least 80-20, strength higher around 20.
> On the lower freqs, it is more of a static rush but time compressed, it is
> also seemingly random, twice in 5 seconds, nothing for 40 sec, once, and
> so on.  Seems to be there almost any time of the day or night.
> I would think static dischard or random arcing, but on 20m the sound is
> very un-arc like, thing what would happen if you mixed a high pitched
> "beep" with someone saying "quip".
> It would not be so bothersome, but on 20 the pulses are often +40 or so,
> and screw with the AGC and generally make listening to weak signals on the
> headphones unpleasant.
> I would assume this was some sore of pule charger or similar, but it
> _never_ displays any kind of pattern.
> I would think intermittant arc except for the sound on 20m.
> Has me thrown and looking for ideas.
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