[RFI] RFI ID Help Needed

[Joe Galicic]

Hi Don,

Thanks for responding.

I am using a 14 inch loop I built from your plans many years ago.  I think this loop is for lower frequencies though.  I used it with success finding noises on 160 meters.  I've never tracked down noise on higher HF frequencies. 

I went outside again today and turned the K3 preamp on and I can now hear the signal but its pretty weak.  However, I can hear all kinds of CW and FT8 signals with no problem ?

I will take another drive through the neighborhood and see if I can locate the signal now that I can hear it.

Joe
N3HEE

>     On 09/09/2021 11:24 AM Don Kirk <wd8dsb at gmail.com> wrote:
>      
>      
>     Hi Joe,
>      
>     You said you have driven around the neighborhood with DF gear but with no luck.  The real question is if you can hear this when you step outside your house with DF gear (don't jump in a car driving around, first get your DF gear working so you can hear the signal when standing outside your house).  That signal you show is so strong (10 to 20 dB over your noise floor) that you should easily hear it with a small DF loop outside your house as long as you have enough preamp gain.  If you can't hear it then you need more preamp gain or the signal likely originates in your house.
>      
>     K0AV suggested using the portable flag, and that would make finding this kind of signal a no brainer based on my experience, but a small (12 to 14 inch diameter) shielded untuned loop made with a hunk of coax would still work wonders as long as you use a preamp (you probably will only need 10 or 20 dB of preamp gain but that's easy to achieve).  The key is to have enough gain so you can hear the signal from right outside your house if at all possible before you start walking or driving around.  I would love having a RFI signal like your currently experiencing to find as it's very distinctive.
>      
>     73,
>     Don (wd8dsb)
> 
>     On Thu, Sep 9, 2021 at 7:55 AM Joe Galicic < galicic at comcast.net mailto:galicic at comcast.net > wrote:
> 
>         > > >     Greetings All,
> >         >     
> >         >     Here is something for all of you RFI sleuths to have some fun with.  An interesting "signal" has appeared in the last couple of weeks at my QTH.
> >         >     
> >         >     Clues:
> >         >     
> >         >     I've eliminated my house.
> >         >     
> >         >     I've driven around the neighborhood with direction finding gear (K3 with small magnetic loop antenna) with no luck so far.
> >         >     
> >         >     A local ham 5 miles away can't hear it.
> >         >     
> >         >     The "signal" is there 24/7. 
> >         >     
> >         >     It is also on 40 meters.
> >         >     
> >         >     Any ideas what this could be ? 
> >         >     See video here https://youtu.be/sl050wudAm0
> >         >     
> >         >     Joe
> >         >     N3HEE
> >         >
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> >     >