Forrester keyless entry problem-strange

Could they be using wireless headsets at a drive-through fast food place in the parking lot that are on the same frequency?

I looked this up on Google and got a ton of hits. Sometimes this will happen mysteriously for many cars in a region then stop. (I know that's not the problem here but it's intriguing.)

For example, from a Las Vegas paper: Valley has keyless encounters of the weird kind

According to the Federal Communications Commission, the low-power radio frequency transmitters inside keyless entry devices are similar to those found in other everyday items such as garage door openers, remote-controlled toys, cordless telephones, building alarm systems and the rapidly spreading wireless fidelity computer networks, which are commonly referred to as "wi-fi."

Paul Oei, an electronics engineer with the Los Angeles office of the FCC, said keyless entry systems operate on unlicensed frequencies. The devices can fail when they are near an antenna emitting high radio frequency energy. But that scenario would affect only vehicles in a limited area, he said.

There has been a rumor going around in one of those dreadful e-mails that your friends and co-workers feel compelled to forward to you all the time. If you lock your keys in your car and you have a remote keyless entry system, you can get outside help to open the car if you have your cell phone with you. Just call someone that has a duplicate key fob that will open your car. Then, hold you cell phone near the door lock and have the person with the key fob call you back. The person with the key fob should then put the key near their phone and push the unlock button. The door should open.

I was skeptical, to say the least, about this rumor, and was about to dismiss it as one more Internet hoax. But I thought I better try it out first. Well, low and behold, it works. I tried it with both GSM and cdma cell phones, and it reliably opens (and relocks) the car.

While the other stuff you mentioned sounds plausible, this one is not. You can read why it won't work here:

That is total bullshit. phones are designed to carry the frequencies of the human voice. Physical microphones pick up sound waves pulses in the air. 20-20000hz, if that. They are incapable of picking up 300MHz radio frequency vibrations. And certainly not capable of broadcasting them. That would be one helluva set of speakers...

Its not a bad idea for a patent though to include a keyfob in a telephone. They could do that functionality easily, but phones are made cheaper and cheaper and they just dont have that engineering expertise.

If you stare long enough you will probably find some transmitter somewhere nearby that is jamming the receiver. Hopefully this is not near an airport as that jamming will keep the car's receiver awake which will drain the battery much faster than with it off.

my subaru does not open or close in a reliable fashion. but I finally figured out that when it will not open, if I push close then open, it always opens. And vice versa. The Japanese favor those lock state switches for some reason. I probably have one going bad.

I agreed with Snopes until I saw that article...Lou Frenzel is no RF hack. He knows his stuff, and he knows it far better than any of us know RF. Something apparently DOES work, but probably not all phones and not all remotes. Where's Mythbusters when we need them?

-John O

As I read this, I was wondering if Mythbuster's hadn't addressed this one in their first season-- wasn't sure.

I'm not familiar with Mr. Frenzel, but if he purports that you can open a remote lock system via "phone to cell phone" link, I would respectfully suggest a reassessment of his RF understanding ;-)

Mythbuster's hasn't done it.

The problem is that Lou writes for "electronic design," a highly respected RF engineering journal. We've received it here for years, and Lou has history with my employer. So, he's not just any old blogger with wild ideas. In any case, there are ways that the fob signal *could* be transmitted indirectly by a phone. I mean, I could create a technical way for it to work but it would be pure conjecture.

Next nice day, a buddy and I are going to try this with a couple different types of phones.

-John O

I've read Mr. Frenzel's post that this works. Yet he never describes exactly what he did. My remote only works about 40' from my car. Three guys at work can use their remotes from the 6th floor of our building with their cars a couple of hundred feet away.

If the person with the sending cell phone was in the remotes range, this would easily explain how this worked.

Adding my naysay on this farfetched notion as well. I'm not an RF engineer, just an electronic tech with over 40 years of experience, most of it in RF. FCC license # on request.