[RFI] Noise location tools

[Dave Cole (NK7Z)]

Actually Don, we are both agreeing with Jim, K9YC with regards to the 
dish.

I could not agree with you more with regards to an attenuator.  My 
biggest problem was overload.  I am in the process of building an 
attenuator for my MFJ three element 135 MHz beam, and radio.  MFJ put 
the receiver at the feed-point, so adding an attenuator involves moving 
the radio to the handle, via an attenuator.

I have been using loops of late, they have a really sharp null, and if 
you hang a hunk of ferrite material at the feed-point, on the coax, the 
pattern gets even sharper!

I also move up in frequency, and prefer that as opposed to adding 
attenuation.  If I can reduce signal that way, I do, else in comes the 
attenuator.

Most locates of late have been just drive around with the truck, 
listening on 40 meters, and shorten/lengthen the screwdriver as needed 
to attenuate signal.

The last locate took 5 minutes that way, and I am in month 2 of taking 
notes to make sure if the FCC is involved, I have done it all correctly. 
  Hopefully the light owner will just add filters, and that will end the 
issue.  I always worry about contacting light operators...  One of these 
days I will find a crazy one...

73s and thanks,
Dave
NK7Z
http://www.nk7z.net

On 01/17/2018 05:41 AM, Don Kirk wrote:
> I agree with Dave, an audio dish would be the last thing I would buy 
> (lowest priority item).  A problem I found while working with the local 
> power company that had an ultrasonic dish is that we could detect arcing 
> on every pole we checked, but out of all the poles we checked there was 
> only one pole that was the root cause of the RFI I was hearing at my 
> house 1.1 miles away.
> 
> The most important feature I have found on any of my portable radio 
> direction finding systems (HF or VHF) that I use for tracking down RFI 
> is the ability to throw in a lot of attenuation when I get close to the 
> source.  If you get close to the source and the signal is full strength 
> even on the nulls of the antenna, there is then no way you can do 
> additional direction finding.
> 
> Don (wd8dsb)
> 
> On Wed, Jan 17, 2018 at 8:23 AM, Dave Cole (NK7Z) <dave at nk7z.net 
> <mailto:dave at nk7z.net>> wrote:
> 
>     Hello Mike,
> 
>     No need for the dish, it just locates arcing, and that is the Power
>     companies job.  Across the two years I had a dish, I think I used it
>     once or twice.
> 
>     Better you save your bucks and build a loop with the saved cash. You
>     will get a lot more use out of the loop than the dish.
> 
>     73s and thanks,
>     Dave
>     NK7Z
>     http://www.nk7z.net
> 
>     On 01/16/2018 08:36 PM, W0MU Mike Fatchett wrote:
> 
>         Thanks all!
> 
>         Other than the ultra sonic dish I have most of the other pieces
>         parts.
> 
>         Appreciate all the links and hints too!
> 
>         W0MU
> 
> 
>         On 1/16/2018 9:17 PM, Dave Cole (NK7Z) wrote:
> 
>             Hi,
>             See:
> 
>             http://nk7z.net/rfi-now-house-cleaning/
>             <http://nk7z.net/rfi-now-house-cleaning/>
> 
>             for a three part series on how I managed to calm down my RFI
>             environment.  Also see:
> 
>             http://nk7z.net/sdr-rfi-survey-p1/
>             <http://nk7z.net/sdr-rfi-survey-p1/>
> 
>             for a tool to characterize your RFI.
> 
>             73s and thanks,
>             Dave
>             NK7Z
>             http://www.nk7z.net
> 
>             On 01/16/2018 11:39 AM, W0MU Mike Fatchett wrote:
> 
>                 What are people using for noise sniffing? I saw the MFJ
>                 dish but I try to avoid their stuff.
> 
>                 I know there is no one perfect tool.
> 
>                 W0MU
> 
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