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U.S. Government Sometimes Jams Keyless Car Locks?
PizzaFace writes "The Washington Post reports that in certain towns (generally near military bases), on certain days (such as the day an aircraft carrier returns to port), keyless car entry systems and remote garage door openers mysteriously fail. While some frustrated motorists blame aliens, the FCC says the jammed frequencies belong to the U.S. military. The good ol' Post even tracks down a government contractor who all-but-confirms the source of the interference."
this topic has already been covered here.
Too bad part 15 of the FCC's guidelines can't apply.
No, not really. The purpose of Part 15 in this case is to protect the military (or whatever individual/group/organization is assigned the particular frequency(s)) from interfearance that your keyless entry system might produce. It is not meant to protect your keyless entry system from others who may be using their assigned spectrum properly.
Come test your mettle in the world of Alter Aeon!
Any FCC Class A or Class B device must accept the possibility of harmful radio interference. If said devices were sensitive to radio transmissions on a particular frequency, and that frequency was delineated for that purpose, there's a possibility of it being a problem.
That being said? I find it highly unlikely that a critical device like that would be left to "We can just sneak along on any frequency we want, because we put out less than 1w"
Weapons of Mass Analysis
This is one of the reasons medical devices have to go through some rigorous testing and use approved frequencies. Even so, mistakes do occur.
When a pacemaker fails, it tends to get noticed. Early pacemakers had trouble with improperly shielded microwave ovens - mostly because the pacemaker itself was improperly shielded. Pacemakers that used a magnetic sensor for the on/off function ran into trouble if a strong magnet was waved over the patient's chest. Some of the early AV sequential pacemakers with the ability to change heart rate based on activity sensors would, if incorrectly programmed, suddenly throw the patient into an artificial 2nd degree heart block when the patient's heart rate exceeded a specific amount.
Urban legends contribute to percieved problems. Notice all the hospitals with "No Cell Phone" signs. Then notice all the cell phones in use by the doctors and the EMS personnel walking around with Handi-Talkies. Oops....
This sig seemed like a good idea at the time....
RTFA. They are allowed to use those frequencies so long as the transmitter (in this case the keyfob) is so low powered that it shouldn't interfere with the licenced equipment.
IIRC, the key-fobs are part 15 devices. This means they use very low power and are allowed to operate so long as they don't cause interfearance to the licensed users of the spectrum. The flip side is that part 15 devices have no protection from interfearing signals from licensed users: Such as when the local military transmitter prevents your keyless-entry system from working.
Come test your mettle in the world of Alter Aeon!
Part 15 is the part that specifies the power limits for non-licensed users to protect the licensed users.
So, it all comes down to what frequencies the car alarm makers are expecting to use. If they pick a miliatary frequency and are trying to use it at low power, then they can't really complain when a miliatary ship comes by and blows them out of the water bandwidth-wise. However, if they pick a frequency open to the public like the 900mHz band, then it's the military transmitting too strong on a low-power band, even if it's just the result signal splash from their attempt to use their assigned band at high power.
So, in a sense, Part 15 does protect your keyless entry system from the miliatary. They're supposed to keep their RF operations away from your space just as much as you're supposed to stay away from theirs.
You don't need to delve into urban legend. Back in 1998, a dozen wireless heart monitors went offline at a major Dallas-area hospital when WFAA-TV turned on its HDTV transmitter for the first time.
I write in my journal
Somewhere within the remote is an actual metal key for use when the electronics aren't working . There should be a button that flips it out or a hidden compartment that you can pull it out of. Look for extra seams on the sides.
This space intentionally left blank.
The interference is in the Military A-Band, which covers 233-403 Mhz. This is used for shipboard radars, as well as radar at airfields. You don't have to use Ghz frequencies for radar, in fact the first WWII radars used were around 100 Mhz, IIRC.
My buddy has the exciter from a shipboard radar as his "Ham Radio" rig. This item generates 1000W CW and about 100 KW in pulse mode, which is what the radars use. It has 4 sections that each handle 1/4 of the band from 10 Khz to 1 GHz. That was then fed to a 10KW Power Amplifier and out. Just the exciter part sits in 3, 6-foot rack cabinets!
The average pulse power in the radars is around 100,000 Watts, and can be pumped up several orders of magnitude to "burn through" jamming if necessary (peak pulse power levels around 1 GWatt!) That field is being constantly swept around the area looking for threats using phased array panels, much faster than the old "Battlezone" radars, so the RF field is effectively everywhere.
Key fobs, RF remotes and Garage door openers are using the 330 Mhz junk band and are right in the middle of the Military A-Band. Doh! Unfortunately, they are also Part 15 users of the spectrum there, and are secondary users of those frequencies - they must not interfere and must accept any interference they experience. Double Doh!!
-- You are in a maze of little, twisty passages, all different... --
Actually, Mercedes-Benz is currently disposing of traditional flat keys. They are gradually being replaced by an IR/RF "SmartKey." As of 2004, the E-Class ships only with a flat "valet key" that independently locks the glovebox.
Do you like German cars?
Being the "primary users" of bandwidth space gives you the right to jam out everybody else... "secondary users" are those whose use is tolerated but they must accept any interference from the primary users and shutdown if they're bothering any primary user.
The car entry system makers picked a frequency that belonged to the military as the primary user... they can't really complain when the military comes to town and wants to use their channel.
Actually there are a couple of exceptions, one is in emergencies, and the other is *gasp* the military.
The generally held concept for emergencies is "anything goes", but you better be prepared to answer for and justify your actions later on.
The other is the military. They don't have "band limits" on their signals. They have generally decided on a band plan that doesn't interfere with other services, but any frequency that is not desginated as broadcast, amateur or public service is subject to them usurping any time at their discretion. Even some of the amateur frequencies are primarily military designation and amateurs are secondary users (parts of 440 Mhz and others).
At the risk of being flamebait, remember, they're the U.S. Government and they can do whatever the hell they want.
-- You are in a maze of little, twisty passages, all different... --
Key fobs, RF remotes and Garage door openers are using the 330 Mhz junk band and are right in the middle of the Military A-Band
We had rock bands come to us (near a Canadian base).
About 3-4 miles from the hotel was a NORAD RADAR. The pulse from the RADAR would manifest itself as a "BZZT" in the band's amplifiers (If was funny seeing the band try to locate the source.....). Heck, you could hear it on your car radio.
Big wattage is NO joke. The spill-over into other freqiencies is a fact of life (anyone with a CB will know it as cross-talk).
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I am a programmer. I am paid to produce syntax not grammar. Deal with it.
In the Navy they use a system called a Red Tag systems. When you are working on equipment and you must kill the power to it you put a Red Tag on it and anyone who violates a red tag suffers severe consequences (up to court martial) So if your dad did not tag the fuse box and decided to work on the radar system (live radar will kill you if you stand in front of the dish) he was not following navy procedure.
I've seen the outcome when the Red Tag procedure is not followed, it cost a friend of mine his hand.
Sorry, teleporters just kill you and then make a copy. A perfect, soul-less copy.
BMW keys are switching over to 415MHz right now. I think the next model update for the Mini (or it might have been the last one - I know it was delayed, but I don't know how long for) are universally 415. So, provided the military play nice (!), everything should be funky.
I work for Chamberlain who makes the Liftmaster and Chamberlain garage door openers. Our newest units just started using 420MHz. I had an old 330MHz unit and my range sucked, so I installed a 420MHz logic board and my range more than doubled. I live right next to Davis Monthan AFB which gives me all kinds of RF interference. I suggest to anyone who has trouble with their Chamberlain, Liftmaster, or Sears GDOs then call Chamberlain and find out if you can upgrade to the 420MHz boards on your model. The price of the boards is crazy expensive ($70), but we here at Chamberlain can give discounts at our leisure. We sometimes will give one out for free if the conditions are right. (WHINE, WHINE, WHINE, "But I can't afford THAT!", "$70?!, The whole unit was $150!", etc)
A lot of posts to reply to, but basically, Naval Ship radars function on lots of bands, not exluding the A Band, mentioned above.
Aircraft carriers have a good deal more power than one would think, and certainly more than a Tico, which is about medium size. One thing to note is that there is no "Medium" size for Navy ships, there are small guys, and big guys. CVN, LHD and LHA are going to have more power because they are bigger...the LHD I served on had 5 primary generators rated at 2500kW a piece, plus another 2 backups at 2000kW each. LHAs are similar, but CVNs have even more, mainly because they have fuel to burn, being nuclear.
Oddly, in the radar category, its only the smaller ships in the Cruiser Destroyer community that have phased array radars, which have higher output than those found on other ships. On carriers, the primary high output radar is the SPS-48E (a rotating radar, as all are, with the exception of the SPY-1 series), and has such power because it is an Air Search radar that scans in 3-D. There are ranges at which we are required to turn off our radars in vicinity of land, but this is soley at the attentiveness of the watchstander, and we frequently got reports during Operation Iraqi Freedom thaty our 48E was jamming the airport radars in Kuwait, and we were requested to lower the power output.
Anyway, a carrier pulling into town running a 48E could certainly jam such devices, but more frequently we get reports that devices start *operating* without warning (garage doors opening, etc.) Certainly you'd see these things more often if you worked on a Naval Base, since lots of ships tend to pull in and out there.
It's not just the navy, it's a standard ISO safety practice, called Lock out/Tag out. Obviously, very important when working on dangerous equipment.
That rule was instituted after a number of W callsigns were issued to stations west of the Mississippi.
The stations already holding W callsigns were allowed to keep them. Dallas has at least two:
WFAA
WRR
No matter what frequency they're on, Part 15 devices are the lowest class users. Basically the Part 15 rules say "Buyer beware!" (though in many more words, as is the habit of government agencies). So it's good engineering for the Part 15 designers to consider all other uses of the spectrum avaialble for their product, and select the frequencies where they will be most compatible. Somehow, I can't see how military radar bands would meet that criteria!
Actually, 433 MHz is in a band allocated to amateur radio (HAM radio) and radiolocation (radar and positioning equipment).
Unlicensed lowpower devices are allowed to use a small part of this band, but they have to accept interference from the other services.
Many radio amateurs are allowed to output about 100 Watts at this frequency, which of course completely swamps the milliwatt signal of the car keys.
The radio location service can output megawatts of pulse power.
The frequency is also used by many other lowpower wireless devices. Interferences is very often a problem. Don't buy products using this technology.
The key fob and auto receiver use "rolling codes". Once the vehicle accepts a code as valid, it increments to the next code in the sequence. Likewise, each time the fob is pressed it increments to the next code in the sequence. The vehicle allows, say, +5/-0 codes in the sequence to allow for missed button presses. It will never open for the same code twice in succession. That defeats simple replay attacks, though if the attacker knows the code sequence alorithm that does allow attackers a toe-hold.
If you use two fobs, there is a separate code sequence for each one. If you run out of retries or otherwise get out of synch with the vehicle, you must (shudder!) use the actual metal key to open the door.
Whoever modded this a troll doesn't know much about how comm frequencies are allocated. The fact is that according to the article, keyless entry systems are secondary users on their allocated frequencies. Ask a ham what that means.
For an excellent example, hams were in the last couple years authorized to operate on the 60m band. That probably means nothing to most people, but it's a specific band that is used by amateurs in other countries, with its own unique propagation characteristics. However, amateurs, who generally get the run of whatever band they're allowed, are limited to one particular operation mode (upper sideband) on five channels, one of which is shared with the UK making international contact on that band possible. The reason for the limitation: the primary users on that band are military and emergency-related, they use upper sideband on those frequencies, and they need to be able to clear the channel for their own use, so they have to be able to talk to other users. (It's an annoyance to hams, who are used to being able to operate any mode they wish, but c'est la vie.)
What looks like the case here is that the remote systems are designed to operate under Part 15 rules, which govern general unlicensed transmission. They're the same rules under which a community low power AM station can broadcast, and are subject to the same terms. In this case, it was an unfortunate choice for car manufacturers, because the frequency chosen is apparently used for certain FCC-allocated classified purposes. Oh well.
Sounds like some of the safety procedures were ignored or bypassed.
I was in the US Navy. We had Lockout/Tagout procedures designed to prevent this. We also had man-aloft switches near the appropriate systems that prevented rotation and radiation. We even had to coordinate with adjacent ships to ensure they didn't radiate us either. Our particular system had an alarm bell that sounded for 15 seconds before it would start up.
We also had a watchstander who announced that workers were aloft on the PA (1MC) every 15 or 30 minutes. I think they said something like: There are men working aloft, do not rotate, radiate or energize designated electronic equipment while men are working aloft... etc.
Of course safety procedures can be ignored...
We complain - audi says it's not their fault, City says it's not their problem.
When I grow an extra head from the radiation I will go to the office of the Sutro Tower people and eat one of their faces.
RS
Shoes for Industry. Shoes for the Dead.
Basically, if a primary user's signal interferes with a secondary user, the secondary user is the one responsible for dealing with the problem (e.g., shielding their equipment, moving, etc). The primary users don't have to take any steps to avoid interfering with secondary users.
Secondary users, on the other hand, have to avoid interfering with primary users. If a secondary user interferes with a primary user, the secondary user has to stop, shield their equipment, move, etc.