[RFI] 160 Meter RFI

Dave Cole (NK7Z) dave at nk7z.net
Thu Dec 6 19:02:47 EST 2018

See if it is hearable on the AM Broadcast band...  If so, take a 
portable radio, and DF using that...  Use the NULL, not the peak for 
DFing, is using the internal loop...

73s and thanks,
Dave (NK7Z/NNR0DC)
ARRL Technical Specialist
ARRL Volunteer Examiner
ARRL OOC for Oregon

On 12/6/18 1:41 PM, Ray wrote:
> Thanks Dave and everyone else who responded.
> To answer your questions:
> It does change sounds right at the end and sounds like a few tones before
> it disappears.
> It seems to be on every 20 to 45 minutes and stays for 5 to 10 minutes. I
> kept data all last weekend and can't see any more of a pattern than that.
> It is always the same as far as I can tell
> It does not show up on any other bands that I can tell but I don't think
> it's confined to exactly 160 meters. I will try to be more definitive on
> that when I look tonight.
> I am fairly certain it is not in my house. I have pretty directive RX
> antennas on 160 that are pretty well decoupled and 200 feet from my house
> and it is definitely strongest to the North East of my house. There are 10
> or 15 houses in that general direction although I am not sure yet if that
> is the area or it is further. One of those has a solar system (still not
> sure why solar cells on your roof are OK but antennas are not).
> I am in a no antenna HOA area but manage to put up some impressive stealth
> antennas in the woods. For the recent ARRL 160 contest I managed 1228
> contacts and 47 countries but could have done much better without this
> noise!
> I will work on hunting it down with a loop but if anyone has any ideas of
> specific equipment I think it would help in my discussion with the
> neighbor(s).
> Thanks again & 73,
> Ray K9RS
> -----Original Message-----
>> From: RFI <rfi-bounces at contesting.com<mailto:rfi-bounces at contesting.com>>
>> On Behalf Of Dave Cole (NK7Z)
>> Sent: Wednesday, December 5, 2018 5:29 PM
>> To: rfi at contesting.com<mailto:rfi at contesting.com>
>> Subject: Re: [RFI] 160 Meter RFI
>> Hi Ray,
>> Trying to guess the source from looking at captures can be tough...
>> That said, here are a few questions:
>> 1.  Does it ever change sound?
>> 2.  Does it run on a schedule?
>> 3.  It is always the same?
>> 4.  Is it just on 160?
>> If it runs on s schedule, kill your house power at one of the run times
>> for it to test if it is in your home...
>> It looks like a SMPS.  Once you get proof it is not in your home, buy or
>> better yet, build a loop.
>> Look over Jim's paper, it does make a difference for the better, if you
>> follow his steps for quieting down your RF environment.
>> Take a look at my page at:
>> https://www.nk7z.net/sdr-rfi-survey-p1/
>> That is part I of a two part series on getting to know your RFI
>> environment using an SDR.  There are several other links on the right
>> dealing with RFI as well...
>> 73s and thanks,
>> Dave (NK7Z/NNR0DC)
>> https://www.nk7z.net
>> ARRL Technical Specialist
>> ARRL Volunteer Examiner
>> ARRL OOC for Oregon
>> On 12/5/18 9:10 AM, Ray wrote:
>>   I have this 160 Meter RFI :  https://youtu.be/QI08sE2FS40 It shows up
>>   once or twice an hour for 5 to 10 minutes. Any ideas what it is?
>>   Thanks,
>>   Ray K9RS
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