Hi,
Grab an AM radio and see if it is there, if so, use the loop to locate
it... If not, build a 2 or 3 foot loop and start hunting...
When you do ID it, I would be most interested in what it is, and a
capture of it alone for my web page of RFI sources at:
https://www.nk7z.net/rfi-snapshots/
I don't see anything like that in the captures at all...
73s and thanks,
Dave (NK7Z/NNR0DC)
https://www.nk7z.net
Award Manager, 30MDG Grid Contest
ARRL Technical Specialist
ARRL Volunteer Examiner
ARRL OOC for Oregon
On 12/21/18 2:19 PM, bill K7WXW wrote:
GA All
My noise reduction project continues. I have been working on noise
sources in my house
but need some help with what seems to be an external source.
For data capture, I am using an RSPro2 and RSP-SAS spectrum analyzer
software, running on a
battery powered laptop. The RSPro2 SDR is connected, via window line, to
my main antenna through the
high Z port.
I ran four series of data capture:
SDR with nothing on any antenna port (establishing a base line, looking
for artifacts).
SDR with 2' of window line connected to the high z port
SDR connected to my main antenna, house power and fiber modem power on
SDR connected to my main antenna, house power and fiber modem power off
Each set includes captures at 3.25, 7.15, 10, 14.15, 18.00, 21.00,
24.50, 28.50,
and 29.50 MHz, all using the same SDR and SA settings.
As expected, some of the noise is produced inside my house (modems,
switching power
supplies, etc). I am cleaning that stuff up by switching out supplies,
adding ferrites
and so on.
But there is a lot of noise between 2 and 6 MHz that is present whether
my QTH is powered
up or down. That's what I want to focus on in my request for help. I've
posted six
screen captures that show what is happening, which can found at this
dropbox link:
https://www.dropbox.com/sh/zncdt66fdnqb2my/AADSHrTgcV5nJOTVgj1zm6vua?dl=0
The first four show a 500KHz span around 3.25MHz. The first three are
all with
house power on, the last with power off:
003 K7WXW RFI 122018
- window line feed, 2' (evening)
001 K7WXW RFI 122118-1
- window line feed, 2' (morning)
001 K7WXW RFI 122118-2 (AGC was accidentally switch on for this set of
captures)
- 130' doublet (main antenna)
002 K7WXW RFI 122118-3
- 130' doublet (main antenna, power off)
The last two two show a wider span, with house power off:
015 K7WXW RFI 122118-3 (5MHz sweep, centered at 4.05MHz)
- 130' doublet (main antenna, power off, fiber power on)
016 K7WXW RFI 122118-3 (5MHz sweep, centered at 4.05MHz)
- 130' doublet (main antenna, power off, fiber power off)
Whatever the source, it is powerful enough to pick up with a 2' section
of window line
connected to an SDR in my basement. It doesn't change when I power down
the house and
fiber modem. It appears to be going 24 hours a day, though I haven't
gotten up in the
middle of the night to confirm that. Any ideas where to start looking?
thx and 73 Bill K7WXW
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