July 26, 2012

Radio Interference - Something's in the Air, it is Time for a Change


In the increasingly wireless world that has become more and more integral to virtually all aspects of our professional and personal lives, other than being aware of the impact of obvious thinks like the recent high-intensity solar flares, we forget that radio spectrum as a medium is fluky. While not exactly national news, we got a reminder of the peculiarities of radio waves in just the past few days.

 Making drivers in Yonkers bonkers

The first item of interest occurred in the New York City suburb of Yonkers, NY. For the past few days it has been impossible for drivers on a small stretch of main thoroughfare Yonkers Avenue to use their electronic key fobs to open the doors of their cars and start their engines. As reported on lohud.com the mystery has been solved and the problem taken care of. 

It was clear that there was an offending signal, but the source was difficult to discern. Thanks to the efforts of radio-frequency expert David Maxon, owner of Isotrope LLC in Medfiled, MA. the culprit was found. Turned out to be a faulty console used to adjust lights at Duo Tapas Bar & Lounge, 748 Yonkers Ave.   As the story notes, Maxon was hired by the owner of an antenna installed on a utility pole on the affected block who believed he might be causing the problem. Maxon noted that these things happen and that he was delighted to be of service.

Garage doors made cranky by U.S. Navy   

In the areas around New London, CT, the issue has been the inability of people to get their garage doors to open or close. In this case, the offending interference was known. It is the U.S. Navy’s ELMR (Enterprise Land Mobile Radio) system. This system, which uses radio frequencies between 380 and 399.9 megahertz, was developed after the 911 attacks. The huge submarine presence in the New London area installed ELMR last year and that is when the trouble started. It is not the first time authorized government spectrum has caused problems with things that operate in adjacent unlicensed spectrum — impacting the operations of not just key fobs and garage doors but such things as baby monitors, meter readers, older cordless phones, and a host of other devices that number in the 10 of millions. Therein lies the rub.

Can’t we all just get along?

Here is what you might wish to know that makes all of this confounding. Years ago the FCC carved out the industrial, scientific and media (ISM) bands. There are several of them and they cover small slivers of radio spectrum with various quality and range characteristics, and are governed by Part 18 and 15 of the FCC’s rules for those who are interested.

The problem that arises with ISM band usage is that unlicensed devices are not offered any protection from interference by licensed users. In fact, they are mandated by federal law to accept interference from licensed users. This means two things: a) licensed users have not obligation to change their systems since their usage takes precedence over all other uses; and they do not have to compensate those whose unlicensed capabilities are impaired.   

In the case of garage doors, this problem has been known for years. Dome manufactures resolved the issue by having dual-frequency remotes so the remote could change to another channel if problems arose. In addition, since the cost of changing a remote to another frequency can run as high as $300, vendors have taken to offering free parts and installation when problems occur.

It is impossible to reproduce here, but check out the U.S. frequency allocation map on the web site of our good friends at CTIA. Yes, it is an eye chart. However, if you blow it up and consider the color coding you will see that the government “owns” a vast majority of the radio spectrum. What is puzzling is that given the proliferation of ISM devices (remember what uses the bands), and now the exploding population of M2M devices, this seems to be a case of “brother can you spare a dime.” With so much spectrum available for their use, one would have thought that the feds after 911 could have found a better place to put ELMR. 

Part of the FCC’s reason for being is to properly oversee the allocation of the scarce resource we call radio spectrum. Since its inception, the Commission has stated time and again that its views as core to its responsibilities to enable innovators to use the spectrum for things that average consumers find useful and on which those with ingenuity can create entire new businesses. Reality has been that good things appear to rightfully go to government for national security and other needs, and to those willing to pay for a license — broadcasters and mobile radio operators of all shapes and sizes. For everyone else, it is “good luck with that.”

It has been since October 6, 1965 that Hall of Fame pitcher Sandy Koufax refused to pitch the first game of the baseball World Series because he was observing the Jewish holiday of Yom Kippur. Sitting in synagogue that day, irony of ironies, my rabbi’s sermon was over-run by the broadcast of the World Series coming over the PA system. Talk about an act of God. 

The point is that 47 years later we can still be bedeviled by the fluky nature of radio waves. Some issues arise that are out of our control, but others can be remediated. Just because companies are using unlicensed spectrum does not mean that the value they deliver is any less than that delivered by those with licenses. In fact, many might say that given the quality of broadcast TV baby monitors are much more valuable to the country.  Nobody is denying that the government should by all means possible use the spectrum to protect national interests. What seems problematic is that given the heavily populated ISM band adjacent to spectrum that the government had been holding in reserve for years, why they created the possibility for interference when it could have been avoided.       

Let’s face it, all the consumer knows is that something they rely on is not working. It probably does not help when/if they are informed it is the government’s fault and they will have to pay to fix the problem. Seems like a good time to think about re-farming spectrum to avoid such issues in the future. I would like to see more ISM bands with some changes in the approach to interference issues, but understand that since radio is a finite resource that maybe the notion of being unlicensed is obsolete. Either way, there has to be a better way of having everyone get along.  We may have come a long way since Sandy Koufax, but we still have a long way to go.




Edited by Amanda Ciccatelli



Related Tags

Security    Wireless   
       

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