2011-2012 RFI
(W.I.P.)

During the midmorning of the Sunday of the ARRL 10-meter contest (Dec 11, 2011) I suddenly became aware of some strong,  
strange RFI while beaming Europe.  Checking other frequencies it was detectable from HF thru 6m.  The 10 and 6-meter     
peaks were to my north east.  It was a combination of stronger slow pulsing on a background of "digital-sounding" racket.
By that evening it had greatly abated or ceased.                                                                         

A week later (Dec 18) it returned.  This time it was noticed on 2m, and on that band again peaked n.e. from the n.e.     
corner of my backyard using an Icom IC-A4 (tuned to almost 137 MHz) and 4-elements (R, DE, D1, D2) of an 11-element      
Cushcraft A144S.  (Previous use/tests have shown little pattern skew at 7-MHz down with that antenna.)                   

With some transportation assistance (I'm a 65 year-old with mobility issues) I was able to take that RDF system to       
the cul-de-sac n.e. of here.  Due to the convoluted street patterns here, that involves a one-way trip of a mile to      
get to residences that are just 100-200 feet behind me!                                                                  



Arriving at that cul-de-sac, Rejillas, the RFI peaked back in my direction about splitting the difference between        
3600 and 3603 there.  Unfortunately at this time, the BNC-UHF adapter in my RDF system failed, making me unable to       
secure any more additional triangulation bearings and turning the IC-A4 with its rubber duck antenna into just a         
proximity detector.  After I'd explained to the residents what I (a resident of the street just south of them since      
Jun 1972) was doing there their cooperation varied (with no access beyond their front yards being granted).  They seemed 
to have a genuine concern for my plight, asking if I had fixed the antenna yet.  I told them that I would likely be back 
again when I had and gave my name and address to 3603.                                                                   

However, shortly after I returned home the arrival of two SAPD officers cast this all in a different light!  It seems    
that 3603 had called them.  I again explained to the officers the situation, showed them my 2-m RDF equipment, and even  
demonstrated the RFI on 10-MHz with a Grundig G8 portable with its whip on my front porch.  They advised me on any future
returns back there that I confine myself to public property unless granted permission by the resident(s).  If obtaining a
copy of the police report for that "incident" were not such a cumbersome process I'd have it.                            

Over the next two weeks the RFI occurred at various intervals, with variations in intensity and peak spectral frequencies
2011_1227 144-MHz
2011_1227 10-MHz
2011_1228 144-MHz 
2011_1229-2045 10-MHz
2011_1229-2050 20-MHz
2011_1229-2051 28-MHz
2011_1229-2053 50-MHz
2011_1229-2102 10-MHz tune
2011_1230-0755 10-MHz
2011_1230-0801 144-MHz
2011_1230-0808 10-MHz
2011_1231-1021 20-MHz tune

Jan 2, 2012 - YouTube

By this time I'd contacted KØRVB, who lives about 1000' to the east on my street.  He was unable to hear any of the RFI  
at his QTH.  However, he did offer assistance by providing me (with my now-fixed 2m RDF antenna system) transporation    
to those cul-de-sacs.  Jan 2, 2012 afternoon - On his 10-m mobile rig he began to hear the RFI as we entered the Rejillas
cul-de-sac, and with a little directivity on it it peaked in the same (s.w.) direction that my 2m system had found it    
back on Dec 18.                                                                                                          

Getting out with the 2m RDF system I approached 3600 and rang the bell.  After some delay the apparent son of the        
resident whom I'd spoken with at length on Dec 18th answered.  The immediate reaction was hostile: "I'd think you'd      
better leave" and "not come back".  Departing, I tried to get some bearings from the sidewalk but was challanged as I was
on the portion where their driveway crossed the public sidewalk.  Not wanting to argue that point, I sidestepped a few   
feet to the north on it, but no better bearings could be obtained than had been on Dec 18th.                             

Leaving, KØRVB decided to take a spin thru the other cul-de-sac, Chapultepec.  The RFI was again heard at the s.e. corner
of it.  I ascribed that to "spill over" from the Rejillas source and did not get out to try any RDF with the 2m system.  

Also by now I had been in contact with W1MG at the ARRL over the prospect of having them involve the FCC in this.        
However, on Jan 3, 2012 the RFI virtually ceased (though some very much weaker hints of it could be heard now and again).
I (over-optimistically, it turned out) thought that this might have had a possible connection with some Xmas device (or  
added wiring that was acting as an efficient antenna for something else) that had been removed/disconnected.             

On Mar 31, 2012 those hopes were dashed with the full-force return of the RFI to those December 2011 levels.  With a few 
brief respites, it has essentially been 24/7 since then.  A HFDF with 4 loop antennas was ordered and a Grundig G4000A   
obtained to enable better DFing at HF (as it is NOT always very prominent on 144-MHz).                                   

Apr 8, 2012: 13-MHz - YouTube
Apr 11, 2012: 144-MHz - YouTube
Apr 16-17, 2012: 14-MHz with and without - YouTube
Apr 23, 2012: 26-2 MHz tune - YouTube




This shows clearly how due to the cul-de-sac layout the peak 144-MHz bearing from the n.e. corner of my backyard cuts    
across more than one property.  It also shows how difficult getting enough parallax for triangulation from "public-      
access" points in a cul-de-sac can be vs. on a "linear" street.                                                          

The HFDF system arrived May 1, 2012, and I am in the process of obtaining additional bearings on the RFI source with it. 
Preliminary bearings with proper loop antennas on 14-MHz and 20-MHz give a bearing slightly to the east of where the     
2m line in the above figure shows.  Confirmatory cross-bearings in the Rejillas cul-de-sac are awaiting some assisted    
transport back there.                                                                                                    

From Sat, May 5, 2012 until the early evening of Mon, May 7, 2012 there was a cessation of the RFI                       
May 5, 2012: 22-2 MHz tune absent RFI - YouTube

Character of the RFI upon its May 7, 2012 resumption                                                                     
May 7, 2012: 17-MHz - YouTube



my residential premises



Additional plots: (thick yellow line) using HFDF system on 14 MHz afternoon of May 9, 2012;
(thick blue lines) 20-MHz midday May 13, 2012; (red line) 137-MHz, 28-MHz, 20-MHz midday May 28, 2012

(This was after a Sun, May 20, 2012 - Mon, May 28, 2012 period of cessation of the RFI.)

(Another cessation period occurred Fri, Jun 1, 2012 - Tue, Jun 5, 2012)

(Cessation: afternoon Thu, Jun 7, 2012 to afternoon Fri, Jun 8, 2012)

(Cessation: a few hours afternoon Sun, Jun 17, 2012)

With the suggestion by W1MG at ARRL HQ, and thru the assistance of K5RAV (West Gulf Division Director) and W5LHC (South  
Texas Section Manager), a "second opinion" was arranged to be obtained from local K5AUW.                                 

Results of K5AUW RDFing this with his MFJ-856 system Jun 18:

"On Monday, June 18, 2012, I assisted Pat Dyer, WA5IYX, in locating a source of RFI affecting his ham radios located in  
his house.  I used an MFJ-856 RFI Detector with a three element beam to locate the RFI.  The first reading was taken from
the NE corner of his backyard.  The RFI was detected at 20 degrees, magnetic,from that location.  Pat and I then drove to
the suspected location.  From the street in front of the suspected house I took three readings.  The first reading was   
taken from directly in front of the house.  The next two readings were taken at 45 degrees either side of center.  All   
three readings pointed to the left-front corner of the house in question.  I noticed a TV satellite dish mounted in the  
suspected area of the house. Since we remained on public property at all times, a closer inspection was not possible.    

I have been assisting hams, private and public agencies in locating RFI for over 30 years.                               
I retired from the VA Hospital in San Antonio 3 years ago where I served as the Lead BioMedical Electronics Technician.  
I was often called upon by my hospital and other hospitals in the Medical Center area to assist in locating sources of   
RFI affecting medical equipment using telemetry."                                                                        

I also took this opportunity to take along my HFDF equipment, and, using 20 MHz, obtained several bearings which placed  
the RFI source in or near the rear (southside) of the 3603 Rejillas premises.                                            



(Dec 28, 2011 view of the southside of 3603 Rejillas from the n.e. corner of my backyard - note sat dish)

With the advice and concurrence of W1MG at ARRL HQ this was mailed (unregistered) to the party on Jun 23, 2012.

(likely unrelated cessation: by 1235 CST Tue, Jun 26, 2012 - resumption by 2015 CST Sun, Jul 1, 2012)