AT&T U-verse system generating interference on 160 meters

Background

Early in July of this year (2013) a CW beacon like signal appeared at the location of WD8DSB on 160 meters at 1.8168 Mhz, and the signal was on 24 hours a day, 7 days a week and the frequency would sometimes alternate between two frequencies that were approximately 30 hertz apart.

Youtube link to recording of the interfering signal : http://youtu.be/5SwWQ7E3O-E

Source of the interference

Source of interference was tracked down on July 16th to a neighbors house, and was caused by a bad cable that was connected to the neighbors AT&T U-verse wireless gateway (Manufacturer : 2Wire, Model number : i38HG). The neighbor said the cable was one he had made himself, and he just had to re-seat the cable and the problem disappeared. The signal had been present for at least two weeks, 24 hours a day, 7 days a week.

How the interference was tracked down

I (WD8DSB) have 3 pennant RX antennas (one pointing 40 deg, one pointing 160 degrees, and one pointing 300 degrees), and the signal was strongest off the 160 degree pointing antenna indicating the interfering signal was originating somewhere South or Southeast of my location.

A portable receiver (DX440) with a small 14 inch diameter shielded loop antenna tuned for 1.816 Mhz and preamp (W1FB preamp operating off a 9 volt battery) was then used in my backyard, and it also indicated the signal was originating from the South (or North, but the pennants had already eliminated North as a possibility).

I then drove approximately 0.6 miles South, exited the car, and was not able to detect the interfering signal using my portable receiving equipment which was a real surprise. I then went back home and decided to walk toward the interfering signal from my house using my portable receiving equipment, and the signal peaked when I was in front of a house that's adjacent to my house on a neighboring street. I was then able to eliminate the preamp from my portable receiving equipment and was still able to hear the offending signal.

A few days later I decided to approach my neighbor (Joe) and ask for his assistance in tracking down a "technical problem" which I then described in detail, and he was more than willing to help out (he already knew I was a ham operating under stealthy conditions). We walked over to his house and the signal was very strong in his garage where there was an AT&T u-verse device which tied his house to the outside world and it was mounted on an outside wall, but after walking through his entire house we found the signal strongest at the corner of his family room (located at the middle of his house) but were unable to find any device at this location that was causing the interference. We then went into the room that was on the backside of this corner, and found the signal very strong at this location too. This location had what appeared to be an all in one copier, as well as an AT&T u-verse wireless gateway, and when Joe started moving the AT&T U-verse wireless gateway it sounded like the signal became scratchy (deviations in signal strength). Joe then unplugged one of the cables going to this device and plugged it back in, and the signal disappeared, and then he mentioned this cable was one he made himself. The wireless gateway was made by 2wire, and the model number was i38HG.

Conclusion

The pennant RX antennas really helped identify the general direction of the interfering signal (which turned out to be approximately 150 feet away), and the portable shielded loop with portable receiver did a great job in locating the signal source, but without the help of a very open neighbor the resolution of this problem would have been very difficult (and likely uncomfortable). Can't thank my neighbor Joe enough for his eagerness to help.

Picture of portable receiving equipment (without preamp)

website created and maintained by Don Kirk (wd8dsb) July 17, 2013