Have you seen this?
https://www.sv1afn.com/rfattenuator.html
Chuck - K9LC
On 1/17/2018 9:43 AM, Dave Cole (NK7Z) wrote:
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@nk7z.net
<mailto:dave@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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