ATT U-verse TV system
|Jul 22nd 2011, 19:22|
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ATT recently rolled out their U-verse TV system here in town and it is being heavily promoted. I am considering signing up but am concerned about RFI problems especially since I use an attic antenna (off center fed dipole, 100 watt). I have found some negative RFI articles regarding U-verse but that information was not current. Are there any RFI issues I should know about regarding this system? Thanks.
|Jul 23rd 2011, 11:37|
Joined: Apr 4th 1998, 00:00
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The reports on U-Verse are stiill mixed. The ARRL Lab has seen the same posts you have found and received reports of U-Verse systems that appear to not cause any problems at all. In a few cases, the U-Verse systems are reported to be noisy, while others seem very susceptible to interference from Amateur Radio.
First, the good news -- the majority of U-Verse installations appear to be problem-free, although most hams that are reporting the 'no-problem' systems do not have the U-Verse installed in their own homes. Still, we do have reports of successful installations. Steve Ford, WB8IMY, the QST Editor has U-Verse installed in his house. Although there were a few initial problems, AT&T resolved them and so far, so good.
At my QTH, U-Verse is in the neighborhood, but not in my house, and I have seen no increase in noise. My antennas are about 300 feet from the U-Verse distibution hub (those big boxes near the street. I run QRP, so it is not likely I would interere with the U-Verse system.
In those cases where hams are interfering with the U-Verse system, under the FCC rules, it is not the responsibility of the ham to address the interference, although when AT&T does work on the system, the cooperation of the involved ham to put a signal on the air for test purposes is appreciated.
The U-Verse signal itself does not appear to be causing interference to Amateur Radio. We do have reports of interference from U-Verse systems, but it appears to be noise from the switching power supply used in the system.
Not all U-Verse installations have immunity problems or cause interference, so the design itself does not appear to be a disaster for ham radio.
ARRL's EMC Engineer, Mike Gruber, email@example.com, has established contact with AT&T staff and found them to be very recepetive to finding the problems, especially since they seem to be random in nature. There does not appear to be a single cause of thie problems, and findings so far have ranged from poor internal grounding and bonding in some of the hubs to noisy (defective?) power supplies to the relatively poor telephone wiring found in some neighborhoods.
The cooperation shown by AT&T is laudable and appreciated. AT&T is investigating individual cases and developing service procedures to address them. One of their engineers, Gordon Beattie, W2TTT, has joined the ARRL EMC Committee, a group of hams that work in various parts of industry, advising ARRL staff and the Board of Directors on EMC matters.
All in all, I am pleased with the progress. The flow of technology is inevitable, and as new technologies come down the pike, it is important that compatibility with Amateur Radio be considered in the design and implementation. It is a combination of cooperation by industry, reports from Amateurs and this kind of work by ARRL that will help make a difference.
I'll spice up my usual signature block to provide some examples of how ARRL is addressing these sorts of problems, not to brag but to help members here understand more about ARRL staff work. Work on these committees saves a seat for Amateur Radio at some important industry tables, often in positions of leadership..
Ed Hare, W1RFI
ARRL Lab Manager
IEEE EMC Society member
IEEE EMC Society Standards Development Committee - Secretary
ANSI asc C63 Committee (EMC) - Member, Vice Chair Immunity Subcommittee, Chair of the below 30 MHz measurement task group
IEEE Connecticut Section Vice Chair
University of Hartford Industry Advisory Committee - Member
QRP Amateur Radio Club International - Board of Directors