Throatenna

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jwax
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Throatenna

Post by jwax » Sun Aug 02, 2009 10:09 am

Yes, I just made up that word Throatenna.
Has anyone ever seen or performed an experiment to determine the gain of holding a remote control (i.e., garage door opener, car keyfob) transmitter against their throat to extend the range? What's the mechanism at work? How much gain is realized? Are there other parts of the body that work even better?

Dean Huster
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Re: Throatenna

Post by Dean Huster » Sun Aug 02, 2009 7:24 pm

I believe that depends on the number of body piercings in the head, fillings (amalgum) in the teeth and the number of metal plates in the head. If any of those happen to be resonant at the carrier frequency of the transmitter, you're in like Flint. If two happen to be resonant (not a likely coincidence), the result could be just the opposite depending upon how the resonant fields interact.

If holding your lower jaw at a certain angle with respect to your upper jaw, then certainly fillings are the active ingredient here and the opening and closing of the jaw affects the distance between fillings, therefore capacitance, therefore the resonant frequency so that you can "fine tune the linear amp", so to speak. In this case, you should also realize that a wet mouth will certainly lower the Q of your resonant mouth, so suck in lots of air and keep things dry for a higher output with a very narrow bandwidth, great for reducing the harmonics.

Another good experiment is to fashion several models of hats from aluminum foil to see if you can enhance the circuitry, possibly moving into a Yagi format with directors and reflectors for better directivity.

Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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jwax
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Re: Throatenna

Post by jwax » Mon Aug 03, 2009 2:15 am

Thanks Dean, for your scientific "tongue-in-cheek" (pun intended) reply.
Nice to see a logical structured response to technical problem-solving! :smile:
Anybody else?
For those who may have no clue as to the basis for my inquiry, perform the experiment-
Hold your remote transmitter in front of you while walking backwards away from your garage door, or car, and find the maximum distance you can have reliable operation of the device. Take 10 more steps backward. Now place the transmitter against your throat, and try again.
Most of the time, holding the transmitter against your throat will significantly increase your range. Question is why.
Aluminum hats optional.

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CeaSaR
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Re: Throatenna

Post by CeaSaR » Mon Aug 03, 2009 7:57 am

Dean Huster wrote:...fillings (amalgum) in the teeth...
I would think that you would be referring to the older "metal" fillings placed in the drilled tooth
prior to the ?90's? when they switched to the non-metal/porcelain fillings.
From http://www.losgatosdentalgroup.com/fillings.html:
In the past, fillings were made of a mixture of liquid mercury, silver powder, and small amounts of powdered tin, copper,zinc and nickel in a 50/50 ratio of liquid mercury to powdered metals. When the liquid mercury is mixed with the powdered metals, it forms a compound known as an amalgam. The amalgam mixture is placed into the tooth and hardens up in a few minutes, although the amalgam does not fully harden for about 24 hours. Amalgam fillings come in only one color- silver. Amalgam fillings have minimum width and depth requirements to avoid fracture, so even small cavities end up with large amalgam fillings.
These fillings have since been shown to be safe.
http://www.usatoday.com/news/health/200 ... cury_x.htm
Dean Huster wrote:...wet mouth..., ...suck in lots of air and keep things dry..., ...great for reducing the harmonics.
I always thought the best way to reduce harmonics in a human was to clamp their mouth shut! :)

Seriously though, anyone in electronics has played with human capacitance at least once. Even
those not in the field (end users / normal people) use it quite often: touch switches, finicky radio
reception, computer/*Iwhatever/kiosk touch screens, it's all over the place. Older people remember
when you would have to hold the rabbit ears on the TV and stand a certain way to get the clearest
reception. Ususally resulted in a very funny picture for future generations. :lol:

I would think that the capacitance of the human body, along with the high water content and iron
(blood) along with the general density would be more of a factor in slightly retuning and/or reflecting
the RF of the transmitter. Of course (>THIS GUY<) could probably get a few miles out of that little
garage door opener! :mrgreen:

CeaSaR

*Iwhatever = Ipod, Iphone, etc.
Hey, what do I know?

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philba
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Re: Throatenna

Post by philba » Mon Aug 03, 2009 11:41 am

Personally, I would like to do some testing of a much more interesting variant of this - the Breastenna.

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dacflyer
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Re: Throatenna

Post by dacflyer » Mon Aug 03, 2009 6:19 pm

is this one of them trick questions ? or was someone really boared when they tried that...lol

maybe if you had a so called GRILL in your mouth it might be even better..heehee

sounds bout as cool as my gas powered tv.

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haklesup
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Re: Throatenna

Post by haklesup » Wed Aug 05, 2009 9:54 am

We know the performance or efficiency of an antenna is effected by its impedance, its electrical length and its interaction with a ground plane. Touching an antenna (not necessarily with your throat) will change all three of these. Sometimes for the better sometimes for the worse WRT the signal you are monitoring.

This is similar to how one would hold an antenna in a strange pose to improve an analog TV reception with rabbit ears back in the days of mechanical tuners without PLL.

Funny, when I read the subject title I thought Throw-Tenna and it was about a wire antenna you could throw out a window or off a ship or something. boy was I wrong.

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Re: Throatenna

Post by jimmy101 » Wed Aug 05, 2009 10:11 am

This is similar to how one would hold an antenna in a strange pose to improve an analog TV reception with rabbit ears back in the days of mechanical tuners without PLL.
Yep. And the signal strength would then change when you walked away from the antenna. You don't need to be touching the antenna to change it's characteristics.

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dacflyer
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Re: Throatenna

Post by dacflyer » Wed Aug 05, 2009 11:06 am

another effect is when a airplane flys by and your station on the radio starts to flutter, until the plane has passed..etc. usually with a weak station..

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MicroRem
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Re: Throatenna

Post by MicroRem » Wed Aug 05, 2009 4:07 pm

Once again, Philba has proven himself to be a genius. If he needs any help with research, I am happy to lend a hand.

best to all,

Tom

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Lenp
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Re: Throatenna

Post by Lenp » Fri Aug 07, 2009 10:18 am

Ah, I put the keyfob in my mouth and bite down on the button. If I turn my head to the side it gets better range. Maybe my head acts like a resonant cavity driving an earmitter! :smile:
Len
Len

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"I must be on the way to success since I already have the junk". (Me)

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haklesup
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Re: Throatenna

Post by haklesup » Sun Aug 09, 2009 8:32 pm

Ah, I put the keyfob in my mouth and bite down on the button. If I turn my head to the side it gets better range. Maybe my head acts like a resonant cavity driving an earmitter!
Or perhaps you have a parabolic pucker :eek:

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