Info and News
April 2005
The FCC’s Budget
Ever wondered what the FCC does, how many people it takes, and how much it costs?
For the coming year, the FCC’s budget request is for $304.7 Million, of which it is anticipated $299 Million will be supplied (or offset) by fees collected by the Commission. The Commission does its work with 1,999 FTE (Full Time Equivalent) employees. The on-line budget is a good place to look for the ten-thousand foot view of the FCC’s priorities and planned regulatory initiatives. It contains a wealth of detail in its 86 pages.
The FCC’s proposed budget to
Congress for Fiscal Year 2006 can be found online at:
http://www.fcc.gov/Reports/fcc2006budget.html
Garage Door Opener Interference on the Increase
There have been several instances of interference with garage door opener remotes at houses located near military installations, the FCC reports in a recent Public Notice (DA 05-424). When the interference occurs, the controllers don’t work properly. Either the range is diminished, or they stop working entirely. Hardwired manual controls are unaffected.
There were occasional reports of this in the past. Recently, the problem seems to have become more common with the introduction of new land radio systems.
Legally, the garage door industry doesn’t have a case, because the openers are regulated under Part 15, which grants them “at sufferance” rights of operation. They can’t cause interference, and they have to tolerate any interference from licensed services. Still, there’s the law and there’s public relations – a lot of homeowners are upset, as well as the manufacturers of the affected equipment.
Here’s what’s going on technically. The problem is that the receivers used in these garage door systems are usually rather simple super-regenerative units. Super-regenerative receivers can be surprisingly sensitive, considering how simple they are, but they have a major weakness: They are highly unselective, and can be easily captured by signals within 10 MHz of their desired operating frequency. This has both a strength and a weakness in this application. The strength is that the receiver and transmitting controller don’t have to be very precisely aligned in frequency. The weakness is that any nearby strong signal over a fairly wide frequency range– such as those from the military base radios – will interact with the receiver and may over-ride the desired controller signal, blocking communications between them.
For security reasons, the DoD (Department of Defense) doesn’t want to publish the exact frequencies in use, which makes it difficult to design around. There is a technical solution – to build more selective receivers and to more precisely align their operating frequencies. The FCC may do that through a formal rulemaking in the future, affecting many types of devices operating in the range of approximately 225 to 400 MHz. In the meantime, the FCC, the Department of Defense, and the National Telecommunications and Information Administration are working with device manufacturers to minimize the consumer impact – possibly by developing substitutable receiver/transmitter pairs that can work at different frequencies from those in local use.
FCC to Reconsider Airborne Cell Phone Restrictions
Have you ever wondered why you aren’t allowed to use your cell phone on an airplane? Did you sometimes think this restriction was just a ploy to get you to pay premium rates for the seat-mounted airplane telephones? A recent FCC Notice of Proposed Rulemaking (FCC 04-288) explains the reason for the policy and holds out the possibility of a solution in the future that would allow in-flight use of passenger-owned cellphones.
The regulation of airplane electronics is handled jointly by the FAA (Federal Aviation Administration) and the FCC. Their interaction is a bit complicated, but in essence, the issues are that the FCC is concerned about harmful interference to terrestrial communications, while the FAA is concerned about aircraft safety, including interference with the plane’s navigation and communications systems.
The restrictions differ depending on the cell phone’s operating mode. Analog mode use is restricted by the FCC. Section 22.295 of the FCC’s rules prohibit the airborne use of 800 MHz cellular telephones on commercial and private aircraft. The concern is that the cellular telephones will transmit at maximum power, and activate multiple cells, causing difficulties for the cellular telephone network. Once the aircraft leaves the ground, the cell phones must be turned off. Personal Communications Services (digital mode) and Wireless Communications Services, regulated by the FCC under Parts 24 and 27 of its Rules, are not subject to airborne use prohibition by the FCC. However, here the FAA steps in—prohibiting all types of mobile telephones and more generally, portable electronic devices (PEDs) unless the aircraft operator has determined that the PED (including cellular phones) will not interfere with the aircraft.
In this proceeding, the FCC is exploring relaxing its restriction on 800 MHz operation, but is careful to note any action it takes will affect only FCC rules and not FAA policies. The key issue for the FCC is protection of ground communications. This can be achieved if an 800 MHz “pico cell” is located on the airplane, with communications to the ground-based cellular system bundled up and handled by an aircraft based link at some other frequency. Since communication from the handsets would only need to be within the plane, the cellular power could be reduced to a minimum level (e.g., -50 dBm is the minimum power for CDMA phones adhering to the IS-95 standard).
The rulemaking is in the information gathering stage. The FCC is soliciting information and proposals as to the plausibility of this idea, and as to whether it could or should be extended to PCS and WCS services.
A Big Safety Recall That Could Have Been Worse
The thought of a product recall involving 14 million units ought to give a safety engineer heartburn. Recently, Microsoft announced a precautionary and entirely voluntary replacement for the power cords on 14 million of the 20 million Xbox consoles that have been manufactured. Apparently, these components occasionally fail, causing overheating and a potential fire hazard. The failure rate is fairly low—less than one in ten thousand. So far, of the millions of consoles produced, only 30 have exhibited this failure. Among these thirty were some reports of minor burns, external damage, or smoke. So, Microsoft has made free replacement power cords available at the Xbox web site, http://www.xbox.com. Consumers can find if their unit is affected by entering their serial number, and their replacement cord will arrive in several weeks.
From your editor’s point of view, this episode has several interesting points. First, this is basically a case of bad luck – the cords bear the marks of a number of certifying agencies, so it appears to be a manufacturing problem, not a design issue. Second, although a potential replacement of 14 million items is daunting, it could have been worse. The cords are customer installable—when a replacement arrives, it takes a few seconds to remove the old one and plug in its replacement. If the cords had been fixed, two-way shipment and factory modification would have been required—which would have been far more costly, and created inconvenience for the user. Third, Microsoft took a highly pro-active approach. It fixed the problem very early. The reported injuries and damage were minimal, and the Consumer Product Safety Commission was not involved.
Bzzzt -- Don’t Try This at Home
This comes under the heading of “You shouldn’t have to be told this, but ...” In response to an episode of the reality TV program “Fear Factor” aired on January 31, 2005, a group of organizations concerned with electrical safety have issued a strong warning that essentially says, “Don’t try this at home!” The episode in question featured a stunt in which contestants received electric shocks. It was staged against the backdrop of a utility substation.
Some unfortunate accidents have occurred in the past when viewers have harmed themselves in copycat re-enactments. This happened a number of times several years ago with MTV’s show “Jackass,” which included a number of outlandish stunts.
Worried that viewers might hurt themselves by imitating this episode, the Electrical Safety Foundation International, along with other concerned organizations, issued a warning that electrical shocks can carry serious consequence, and that “utility substations and electrical equipment” are not “suitable locations for horseplay.” ESFI points out that it doesn’t take the thousands of volts present in HV transmission lines to cause death – only a relatively small amount of current need pass through the body to cause death. According to IEC 60990, 2nd ed., "Methods of measurement of touch current and protective conductor current” only takes about 10 milliamperes to reach the “let-go” threshold, the level of conduction where a shocked persons muscular control fails so it becomes impossible to let go of a shocking conductor. Surviving an electric shock is more a demonstration of luck than toughness.
Some of the other well-known organizations joining in this message were The National Electrical Manufacturers Association (NEMA), the National Fire Protection Association (NFPA), CSA International, and Underwriters Laboratories (UL).
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