[RFI] Xfinity Router RFI (Xfinity router name XB3)
Don Kirk
wd8dsb at gmail.com
Thu Feb 13 14:27:47 EST 2020
Hi Frank,
You bet I will continue to use tuned and untuned loops too. I have tuned
loops and untuned loops in my arsenal. I have untuned loops all the way
down to 1 inch in diameter.
Don
On Thu, Feb 13, 2020 at 1:45 PM <donovanf at starpower.net> wrote:
> Don,
>
> Do you intend to keep an untuned loop in your bag of tricks?
> It would seem that its very sharp null offers unique advantages.
>
> 73
> Frank
> W3LPL
>
> ------------------------------
> *From: *"Don Kirk" <wd8dsb at gmail.com>
> *To: *jim at audiosystemsgroup.com
> *Cc: *"RFI" <rfi at contesting.com>
> *Sent: *Thursday, February 13, 2020 6:39:25 PM
>
> *Subject: *Re: [RFI] Xfinity Router RFI (Xfinity router name XB3)
>
> Hi Jim
>
> Thanks, and I thought about submitting an article to QST since I have
> written articles for them in the past, and will do that for my portable
> flag for HF direction finding. Numerous people have requested info from me
> already today, and will put something together soon and provide a link to a
> simple website (probably sometime next week).
>
> I had been working on a tuned loop with sense antenna but then thought
> about designing the portable flag and glad I did as it really keeps things
> simple and easy to duplicate (very robust concept and hard to mess up).
> Just came in from the cold testing its directional properties from the AM
> broadcast band all the way up to 25 MHz (max frequency of the signal
> generator I was using today), but as I previously said I designed it using
> 4NEC2 so it has a cardioid pattern up to at least 30 MHz and actually
> higher in frequency. It has very negative gain (especially down on 160
> meters) but works great when using an appropriate preamp. In most cases a
> 20 dB preamp like the W7IUV preamp is more than adequate but in some cases
> even more preamp might be helpful.
>
> Lots more info to follow, but since I have a day job it will take some time
> to put together my article for submission to QST but I should be able to
> post some pictures, dimensions and other design info sometime next week on
> a simple website I will create for this antenna.
>
> 73,
> Don (wd8dsb)
>
> On Thu, Feb 13, 2020 at 12:37 PM Jim Brown <jim at audiosystemsgroup.com>
> wrote:
>
> > This is a very interesting post, Don.
> >
> > Your loop and a description of your troubleshooting would make a great
> > piece for QST or NCJ. Also, spectrum pix would make a great addition to
> > NK7Z's collection of the signatures of known noise sources.
> >
> > For chokes wound on the 2.4-in o.d. #31 cores, I suggest following
> > recommendations for THHN for cables like AC line cord and RG400 for
> > smaller cables in the New Cookbook.
> >
> > 73, Jim K9YC
> >
> > On 2/13/2020 6:59 AM, Don Kirk wrote:
> > > Hi Jim (and gang),
> > >
> > > I should also mention the wireless router we are talking about is
> really
> > > called a Residential Gateway.
> > >
> > > The Xfinity Telephony Gateway provides four Ethernet connections for
> use
> > > as thehub of your home/office Local Area Network (LAN). The Xfinity
> > > Telephony Gatewayalso provides 802.11a/b/g/n/ac wireless connectivity
> > > for enhanced mobility andversatility. In addition, the Xfinity
> Telephony
> > > Gateway provides for up to two sepa-rate lines of telephone service and
> > > Digital Enhanced Cordless Telecommunications(DECT) funtionality to
> allow
> > > using cordless telphones within the home. The Tele-phony Gateway also
> > > offers integrated MoCA 2.0 home networking providing Inter-net access
> > > and transfer of multimedia content between devices over coaxial cablein
> > > the home.
> > >
> > > Just FYI,
> > > Don (wd8dsb)
> > >
> > > On Thu, Feb 13, 2020 at 9:40 AM Don Kirk <wd8dsb at gmail.com
> > > <mailto:wd8dsb at gmail.com>> wrote:
> > >
> > > Hi Jim,
> > >
> > > Thanks, but I really wanted to know if others have noticed a 1 MHZ
> > > wide signal that has a white noise waterfall and spectrum plot
> (both
> > > RF and Audio) from the Wireless Router I mentioned centered around
> > > 21 MHz. The main reason I asked this question is that it took us a
> > > couple of days to track down the source because at times we had
> > > conflicting bearings from our numerous direction finding antennas
> > > and I now suspect we ran across similar signals originating from
> > > other homes in a pretty densely populated neighborhood.
> > >
> > > This case made me introduce a new portable direction finding
> antenna
> > > to my toolkit for HF which turned out to be a life saver. I have a
> > > lot of experience with small terminated flags and pennants on 160
> > > meters, and this gave me the idea to design and build a very small
> > > portable terminated flag that I designed to have a cardioid pattern
> > > all the way up to at least 30 MHz, and this antenna was a great
> help
> > > due to its unidirectional properties. Used this portable flag (2
> > > foot x 4 foot) with a W7IUV preamp operating off a 9 volt battery
> > > and this system was invaluable. A big advantage of the terminated
> > > flag is that it's truly broadband versus the portable tuned loops
> we
> > > also used. Having the broadband antenna allowed us to easily see
> > > the 1 MHz signature of the signal. (where it rolled off, etc.).
> > >
> > > Please keep in mind that when we are dealing with a homeowner
> that’s
> > > also a stranger that’s not a ham we should try and be the least
> > > invasive and least time consuming as possible while still obtaining
> > > the end goal which is to eliminate the RFI we are experiencing. We
> > > got lucky that this particular homeowner immediately volunteered to
> > > shut off his breakers before we even asked him to do that until we
> > > found what circuit was generating the noise, and then he went into
> > > his master bedroom and started unplugging devices until the device
> > > generating the noise was located (Mike and I did not enter his
> > > home). He then mentioned he was going to go to xfinity on Monday
> > > anyway and would request a new wireless router. It also helped
> that
> > > this homeowner had some knowledge of who Mike was and he mentioned
> > > that he had gone to high school with Mikes son many years ago.
> > >
> > > As I already mentioned we indeed will have the home owner try a
> > > toroid choke (based on the 31 material) on his AC line cord as well
> > > as a traditional differential mode power line filter if new
> > > equipment from Xfinity does not solve the problem. If these
> methods
> > > don’t work then we will dig deeper (chokes on other cables entering
> > > and exiting the wireless router, etc.).
> > >
> > > On a side note, Mike (W9RE) is going to give the homeowner an
> > > extension cord wrapped on our 31 material toroid core to try on his
> > > existing router prior to this weekend since Mike as I'm sure you
> > > know is big contester and he sure would like to have his 15 meter
> > > noise reduced (or eliminated) for this weekends contest, but again
> > > we are not trying to be too over bearing on this homeowner since he
> > > has already been so cooperative.
> > >
> > > Will post an update in the near future.
> > >
> > > Thanks and 73,
> > > Don (wd8dsb)
> > >
> > >
> > >
> > >
> > > On Wed, Feb 12, 2020 at 9:39 PM Jim Brown <
> jim at audiosystemsgroup.com
> > > <mailto:jim at audiosystemsgroup.com>> wrote:
> > >
> > > On 2/12/2020 6:18 PM, Don Kirk wrote:
> > > > If the replacement router does not fix the problem then
> > > > Mike will test a toroid core choke as well as a corcom type
> > > filter on the
> > > > wireless router power cord.
> > >
> > > It's ALWAYS a good idea to put a suitable ferrite choke on any
> > > wiring
> > > connected to a noise source -- it's usually those wires that
> > > radiate the
> > > noise. And that includes the AC line cord or DC power cable.
> For
> > > 15M,
> > > I'd start with three turns on a medium-size #31 clamp-on, and
> > > I'd do the
> > > same with any Ethernet cables.
> > >
> > > If you haven't already done so, I'd try to shift the network to
> > > WiFi, so
> > > that the only cables are the power supplies, the cable between
> > > the modem
> > > and the router, and the DSL or internet cable feeding the
> modem.
> > >
> > > Lots of detailed advice on my website in the piece about
> > increasing
> > > contest scores by killing noise. k9yc.com/publish.htm
> > > <http://k9yc.com/publish.htm>
> > >
> > > 73, Jim K9YC
> > > _______________________________________________
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> > >
> >
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