The Boston Diaries

The ongoing saga of a programmer who doesn't live in Boston, nor does he even like Boston, but yet named his weblog/journal “The Boston Diaries.”

Go figure.

Saturday, April 02, 2005

Science in action

Another unexplained phenomenon: Do you know of anyone who can explain why I can hold my car's remote keyless entry fob to my chin and have its range tripled, or even quadrupled? Try it. Yeah, it works. Really!

There's the challenge for this week, folks. A cavity-resonance, antenna effect, or just what? Let us know your theories … !

An Interesting Phenomenon—The James Randi Educational Foundation Newsletter

I don't have a theory, but I did decide to test the phenomenon (do doo de do do!) to see if it really happens. Casa New Jersey is at the end of a dead-end street with very little traffic, so it was a simple matter to park Lake Lumina (my car—there's a long story attached to the name) at the end of the street and using a 300′ tape measure, mark off the distances.

[Lake Lumina at the end of the street] [The front of Lake Lumina is pretty long]

The tape measure was tucked underneath the front driver wheel (a convenient anchor point), but given that I don't really know where the keyless entry fob antenna is on the car, the measurements I did take could be anywhere from +4′ to -15′. So, with that in mind …

At certain intervals, I held the keyless entry fob five different ways:

[Fob at waist height] [Fob at shoulder height] [Fob against my chin, mouth closed] [Fob against my chin, mouth open] [Fob above head level—the so called “Don Martin” pose]

I'm sure I looked silly to the neighbors, but it's silliness in the name of science! Undaunted, and with the help of wlofie (who was standing by Lake Lumina) who used hand signals to indicate if the doors locked or unlocked, I proceeded to look silly while seeing how far I could lock and unlock my car.

The keyless entry fob is the original unit that came with my car and as such is seven years old, still with the original battery. Also, the fifth stance, the so called “Don Martin” pose, was suggested halfway through the experiment and I neglected to take samples at the shorter distances. I started out going 20 feet per attempt, then as the signal appeared to drop out, started shortening the distances to locate where the signal dropped.

Now, onto the results:

The range of a keyless entry fob under different holding techniques
Distance Fob at waist height Fob at shoulder height Fob against my chin, mouth closed Fob against my chin, mouth open Fob above head level—the so called “Don Martin” pose
Distance Fob at waist height Fob at shoulder height Fob against my chin, mouth closed Fob against my chin, mouth open Fob above head level—the so called “Don Martin” pose
20′ Yes No Yes Yes (not tested)
40′ Yes No Yes Yes (not tested)
50′ No Yes Yes Yes (not tested)
55′ No No Yes No Yes
60′ No No No No Yes
70′ No No Yes Yes Yes (sporadic)
80′ No No Yes Yes Yes
90′ No No Yes (sporadic) No No
100′ No No No No No

Holding the keyless entry fob to my chin did extend the range to twice that of just pointing towards the car, but nowhere three or four times the claimed distance. Also, the “Don Martin” pose also extended the range about twice the distance. So it's hard to say if it's due to a cavity-resonance atenna effect, or just the higher altitude the fob was held at increased the range (and there is that spurious result at 90′—perhaps the signal reflected oddly?). Who knows? I just generated some data that can be used in coming up with a theory.

Now, off to email the results to the James Randi Educational Foundation

Obligatory Picture

[It's the most wonderful time of the year!]

Obligatory Links

Obligatory Miscellaneous

You have my permission to link freely to any entry here. Go ahead, I won't bite. I promise.

The dates are the permanent links to that day's entries (or entry, if there is only one entry). The titles are the permanent links to that entry only. The format for the links are simple: Start with the base link for this site: http://boston.conman.org/, then add the date you are interested in, say 2000/08/01, so that would make the final URL:

http://boston.conman.org/2000/08/01

You can also specify the entire month by leaving off the day portion. You can even select an arbitrary portion of time.

You may also note subtle shading of the links and that's intentional: the “closer” the link is (relative to the page) the “brighter” it appears. It's an experiment in using color shading to denote the distance a link is from here. If you don't notice it, don't worry; it's not all that important.

It is assumed that every brand name, slogan, corporate name, symbol, design element, et cetera mentioned in these pages is a protected and/or trademarked entity, the sole property of its owner(s), and acknowledgement of this status is implied.

Copyright © 1999-2019 by Sean Conner. All Rights Reserved.