[RFI] DFing an HF RFI source

Kelly Johnson n6kj.kelly at gmail.com
Tue Oct 17 11:22:22 EDT 2006

Thanks.  I was able to track the source down to one of 3 houses using
a whip antenna.  I'll need something more directional to narrow it
down further OR go house to house.  The houses are about 200 yards
away or so.  I'm really curious what device is causing this problem.
It only seems to affect 17 meters and it sounds like a "tick, tick,
tick" at about a 1Hz rate.

On 10/16/06, Jay Bareman <Radio_Q at mchsi.com> wrote:
> Hello and sorry for the delay in responding to this thread.   I had almost
> the same noise and DF problems here and asked the group about it back in
> November 2005
> http://lists.contesting.com/archives//html/RFI/2005-11/msg00005.html
> In my case, with the bands being so dead, I just ignored it as the owner of
> the house is a bit of a 'weird dude' so I chose not to confront him without
> some more suspicions of what I might be looking for.
> Fortunately for me, something changed and I have not had the noise for
> several months now.
> I guess the bottom line to my message is that 1) keep walking around and you
> will likely find it within a block or so of your qth.  2)  Look for coax
> coming out of his telephone network box (DSL ?) 3) If you have a 'nice
> neighbor' and are able to figure it out, I know the list would love to hear
> what you found!!
> 73's
> Jim  K5QQ
> -----Original Message-----
> From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
> Behalf Of Kelly Johnson
> Sent: Monday, October 02, 2006 6:57 PM
> To: rfi at contesting.com
> Subject: [RFI] DFing an HF RFI source
> I have an RFI source in my neighborhood that I'd like to track down,
> but could use some advice.
> The noise source sounds like a "click" or small burst of energy at
> approximately 1Hz.  In other words, I hear a burst of RFI a little
> faster than once per second.  It seems to be relatively narrow band.
> I don't hear it below 17 meters.  It is strongest on 17 meters, but I
> can sometimes hear it on 15 meters and maybe even 10.  I've never
> heard it above that.  I have DF'd the general direction using my tower
> mounted HF yagi and the RFI peaks at about S7 or S8 on 17 meters which
> is fairly strong, however I can't hear it when I walk the neighborhood
> in that direction with my FT-817 and a whip.  I obviously can't carry
> a 17 meter yagi around the neighborhood.  What other decent antenna
> can I use to DF something doesn't appear to be broadband enough reach
> into the VHF region?
> FYI - The strength of this noise source varies from day-to-day and
> some days I don't hear it at all, but it's there most of the time.
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