[RFI] Anyone know what this might be
wx5l at charter.net
Sun Jan 23 11:09:41 EST 2005
Noise like this can be from so many different consumer devices. It's just
incredable how much RFI is out there with new technology. I would think a
S-9 would be within a block or 2. Did you go out at least 2 city blocks
Here's a reference web-page that was helpful to me recently.
>From your recording it's not typical power line noise but from a device like
a thermostate, cell phone wall charger, electric blanket or ionic air
filter. Give a close listen to the .wav file sent in by N4EKV. It sounds
similar but has a different timing but that could be just different
manufacturers. Take a listen to some of the others not related to typical
----- Original Message -----
From: "Kelly Johnson" <n6kj.kelly at gmail.com>
To: <rfi at contesting.com>
Sent: Sunday, January 23, 2005 1:03 AM
Subject: Re: [RFI] Anyone know what this might be
>I DF'd the noise tonight then went out scouring the neighborhood with
> my FT-817 and a whip. I couldn't find the source. It's S9 in a 6KHz
> bandwidth in AM with my 3 element yagi aimed at the source so it's
> fairly strong, but not strong enough to hear on my whip.
> I recorded the noise as .wav file and put it on my website. At first
> I thought it sounded like white noise, but now I realize that it
> sounds more like a motor starting up or something. The noise lasts
> about 1 second and repeats every 24 seconds. I'd love to have people
> listen to it and help me identify the source.
> You can find the file on my website at:
> Click on the RFI-1 link near the bottom of the page.
> On Sat, 22 Jan 2005 19:21:07 -0600, WX5L <wx5l at charter.net> wrote:
>> First you need to get a direction of the noise. I would hope you have a
>> rotatable HF beam. Carefully rotate and determine the direction of
>> level. Only then can you set out with your portable receiver. It seems
>> the source maybe further out than you think. You will need to set out on
>> foot in this direction with your portable set on one of the frequencies
>> the noise. Clip a wire from your HF antenna to the portable so you can
>> to a frequecy with a peak so that you can set out on foot with the
>> receiver set.
>> ----- Original Message -----
>> From: "Kelly Johnson" <n6kj.kelly at gmail.com>
>> To: <rfi at contesting.com>
>> Sent: Saturday, January 22, 2005 1:26 PM
>> Subject: [RFI] Anyone know what this might be
>> > I've been noticing an RFI source lately. It sounds like a short 1
>> > second blast of "white noise" which occurs at 25 or 30 second
>> > intervals. It appears to be there 24/7. I hear it on 40 through 17
>> > meters. It peaks at about S7 or S8 in a 2.4KHz bandwidth. That's
>> > pretty strong considering that my noise level at nigh in a 2.4KHz
>> > bandwidth is only about S1 or S2. It's not strong enough for my
>> > portable receiver to pick up so I've had trouble DFing it. I have yet
>> > to try to DF it with my HF yagi.
>> > Anyone have an idea what this may be?
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