Using a Moxon antenna is another way to get a sharper null - there was
an article in QST describing such an antenna, which I use with a
shirt-pocket handi-talkie with 136 MHz AM aircraft band. The null off
the back is deep and narrow.
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at <http://beta.reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.
On 1/12/2021 1:41 PM, David Eckhardt wrote:
Most recently, I have isolated a source on a power pole by using both the
MFJ device AND a home brew 0.5-meter shielded loop connected to a
battery-powered receiver tuned to the frequency of maximum RFI. The null
perpendicular to the loop plane is extremely sharp and, from that
experience, I dare say sharper than the MFJ device or at least an equal.
Another strength of the shielded loop is that you can isolate the source
*at* the interfering frequency(ies). Also, confirming a source with two
entirely different technologies can be helpful in nailing the source.
Once isolated, our power provider, PVREA (N. Colorado), had the problem
fixed the next day and waited for us to confirm their fix. Not all
providers are so responsive.
Dave - WØLEV
On Tue, Jan 12, 2021 at 1:25 PM Dave Cole <dave@nk7z.net> wrote:
Hello,
I have some RFI location information at:
https://www.nk7z.net/i-have-rfi-now-what-locating-it/
I use the MFJ-856, (https://mfjenterprises.com/products/mfj-856), when
looking for VHF RFI. It will pinpoint an RFI source and in most cases
you can tell which part of the house the RFI is coming from, if you are
on the sidewalk in front of the home.
Your RFI could be anything, is it on a schedule, does it change
strength, lots of questions to answer first.
IDing via signature can sometimes work, (not too often), but nothing has
worked for me better than getting out on foot and looking for the RFI
source.
Once you have it located that is another entirely different matter.
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 1/11/21 8:45 PM, RALPH GRANCHELLI wrote:
Hello inteference investigators,
I have new RFI issue that started about a week ago.
I have eliminated the house / items as a source.
Killed all breakers, ran the XCRV from batt. No change. Disconnected ext
antenna, used in house antenna and no noise. So noise coming in from ext
antenna.
The RFI is strongest on 80 meters however it is present up to vhf with
diminished magnitude.
I took a screen shot of it on the spectrum scope.
Does anyone recognize the signature?
https://www.youtube.com/watch?v=uOdzw2ev5eE
<https://www.youtube.com/watch?v=uOdzw2ev5eE>
<https://www.youtube.com/watch?v=uOdzw2ev5eE
<https://www.youtube.com/watch?v=uOdzw2ev5eE>>
TNX & Rgds,
N6XLQ
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