[RFI] Broadband RFI...

David Robbins k1ttt at verizon.net
Tue May 31 09:33:58 EDT 2016

the only difference in hunting a broadband noise is that you have to be sure that when you go from your shack to mobile that you are hearing the same
noise and aren't being distracted by a different one.  having someone to help you get started who can mark the time the noise starts in the shack while
you are listening in the mobile can be useful so you can be sure you are hearing it.

if it is something like one of the grow light supplies they can be very unstable when they turn on.  look at the spectrum displays on 12/13 that show one starting up on my web page at: http://wiki.k1ttt.net/2012%20Maintenance%20and%20Upgrade%20Blog.ashx#160mrfi   (be patient it may take a few minutes to load as there are lots of pictures on that page)

May 31, 2016 09:10:47 AM, dave at nk7z.net wrote:


At some point in the last few weeks, someone mentioned something along
the lines of a broadband RFI generator type of switching supply, of a
type that sprays a huge swath of spectrum with what appears to be
broadband noise...  

Could someone expand on this please.  I ask because I have a new and
different RFI issue which started a few days ago, and want to understand
the generator a bit better...  Does this device have a name? 

My new RFI looks to be one of these types of devices.  I am still in the
data collection stages, so I don't know for sure if it is on a timer,
but I suspect it is.  I have two days of data, and it looks like it
comes on and goes off at set times...  But this is too early to tell.  I
will run data collection while I am at Sea-Pac, which should give me
three days of additional data.

It is VERY wide, at least 200 KHz, and flat, I mean really flat, like it
was designed to be flat...  See:
The images at the above URL show three different views of the RFI, FFT
of audio passband vs. time, (about 8 hours), the P3 panadaptor view,
showing 200 KHz of spectrum, and some S-Meter vs time graphs.  Each view
has a description below it.  I would be interested in any thoughts the
group has on these.  All readings taken in AM mode.

DFing will be interesting, look for lowest background noise I guess.  No
real signal to latch onto.  This will be the first time hunting a
broadband signal.  Any hints would be appreciated.

Lucky for me it is only two S-units of RFI, (today).  I have not looked
at 30, or 80 yet...  

I got about 6 months of RFI free time from the last hunt...  It is like
playing Whack-A-Mole here in Oregon.  

Thanks in advance to all who comment...

73's, and thanks,
Dave (NK7Z)
For software/hardware reviews see:
73's, and thanks,
Dave (NK7Z)
For software/hardware reviews see:

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