Not letting a good thread die, here is some more info.
Here is a link to a Dropbox folder where, if it works, there are six files.
https://www.dropbox.com/scl/fo/3c95ijqs0bs11i1mtveyc/h?rlkey=2wsbz4jkjo86a45n8fkjsy5lm&dl=0
Two of them are baseline plots taken from a Perseus SDR with the 160-meter
antenna disconnected. There is a spectrum plot and a waterfall plot. Two
others are the same setup with the antenna connected. These are centered on
1840 kHz with a span of 320 kHz. There are two audio files recorded at two
different frequencies using my Kenwood TS-890 in AM with a 10 kHz BW. There is
a fair amount of FFT averaging and smoothing on the spectrum plots but the
waterfall shows the multiple frequencies in this mess.
Some, but not all, of the frequency shaping can probably be attributed to the
antenna but this is definitely not what I would expect from powerline noise.
Has anyone seen anything like this?
Wes N7WS
On Monday, January 29, 2024 at 05:39:55 PM MST, Hare, Ed, W1RFI
<w1rfi@arrl.org> wrote:
I agree; with no change, the noise is probably external, but do keep in mind
that some UPS devices or devices connected to them may still be powered on,
although in that case, I'd expect to see some change.
And no need for an apology. Tracking down RFI can be darn tricky. If anything,
you can be proud of having a mind open enough to backtrack and find what really
is a minor misstep. When I worked in the ARRL Lab, many hams with RFI problems
would not go back and look again at things they were "sure" they tested right.
You are going to find this.
From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Wes Stewart
via RFI <rfi@contesting.com>
Sent: Monday, January 29, 2024 4:55 PM
To: rfi@contesting.com <rfi@contesting.com>; dave@nk7z.net <dave@nk7z.net>
Subject: Re: [RFI] Mystery Noise (Aren't they all) Sadly, no. A mea culpa and
apologies to all who replied. When I removed power to the shack, of course the
KAT500 antenna tuner turned off. I had put it in bypass mode, however, that
wasn't good enough since it defaults to port one and my vertical was on port
three. So effectively, I disconnected the antenna when I removed power. When
I reran the test today with a jumper around the tuner, there is no change in
the noise with the house un-powered.
I am satisfied that the noise is external.
I don't know whether I can make attachments on this site. If so, I have some
screen shots.
On Monday, January 29, 2024 at 09:10:35 AM MST, Dave (NK7Z) <dave@nk7z.net>
wrote:
Hello,
This indicates that the RFI is in your home. This is great news, it
means you can fix it as fast as you want, and you don't have to wait on
people... Take a look at:
https://www.nk7z.net/i-have-rfi-now-what-locating-it/
I have a handy flow chart there that may help you locate the RFI...
Please report back on what you find it to be...
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources
On 1/28/24 19:50, Wes Stewart via RFI wrote:
> In conversation with the tech a few days ago I offered to battery power
> my TS-890 and turn off the whole house breaker. When I did the noise
> went from S9+10 dB down to about S4, but it was still there!
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