Key transmitter?

In article >,
"Ted Mittelstaedt" > wrote:

> "Josh S" > wrote in message
> ...
> > In article >,
> > "maxpower" > wrote:
> >
> > > "Josh S" > wrote in message
> > > ...
> > > > One of my 2004-300M key transmitters doesn't seem to be working.
> > > > The batteries are OK, but I can't get it to function on the car.
> > > > Is there a way to determine if it's transmitting, before I chuck it
> for
> > > > another.
> > >
> > > The dealer has a tool that all it takes is a push of your key fob and it
> > > will pick up the signal to see if it is putting out. more then likely
> your
> > > key fob is bad. Check to see that the contacts in the remote has not
> > > separated from the circuit board.
> > >
> > >
> > > Glenn Beasley
> > > Chrysler Tech
> >
> > THX Glen.
> >
> > I thought they must have such a device, but my dealer said they don't.
>
> Take a working key fob, go to an AM radio, tune the radio to static
> in between stations, put the keyfob next to the radio and press a button,
> you should hear a blast of static from the working transmitter. If you do
> not
> hear the same blast of static from the non-working keyfob, the fob is dead.
>
> Ebay has lots of fobs.
>
> Ted

OK I'll try that. Lots of radios here.

In article >,
Josh S > wrote:

> In article >,
> "Ted Mittelstaedt" > wrote:

> > > > "Josh S" > wrote in message
> > > > ...
> > > > > One of my 2004-300M key transmitters doesn't seem to be working.
> > > > > The batteries are OK, but I can't get it to function on the car.
> > > > > Is there a way to determine if it's transmitting, before I chuck it
> > for another.
> > > > >
> >
> > Take a working key fob, go to an AM radio, tune the radio to static
> > in between stations, put the keyfob next to the radio and press a button,
> > you should hear a blast of static from the working transmitter. If you do
> > not
> > hear the same blast of static from the non-working keyfob, the fob is dead.
> >
> > Ebay has lots of fobs.
> >
> > Ted
>
> OK I'll try that. Lots of radios here.

Ted; I tried the radio, but it didn't detect even the good transmitter.
Have you a suggested radio frequency?

"Josh S" > wrote in message
...
> In article >,
> Josh S > wrote:
>
> > In article >,
> > "Ted Mittelstaedt" > wrote:
>
> > > > > "Josh S" > wrote in message
> > > > > ...
> > > > > > One of my 2004-300M key transmitters doesn't seem to be working.
> > > > > > The batteries are OK, but I can't get it to function on the car.
> > > > > > Is there a way to determine if it's transmitting, before I chuck
it
> > > for another.
> > > > > >
> > >
> > > Take a working key fob, go to an AM radio, tune the radio to static
> > > in between stations, put the keyfob next to the radio and press a
button,
> > > you should hear a blast of static from the working transmitter. If
you do
> > > not
> > > hear the same blast of static from the non-working keyfob, the fob is
dead.
> > >
> > > Ebay has lots of fobs.
> > >
> > > Ted
> >
> > OK I'll try that. Lots of radios here.
>
> Ted; I tried the radio, but it didn't detect even the good transmitter.
> Have you a suggested radio frequency?

Any modern transmitter, like your key fob, generates it's radio signal
digitally. (the actual signal itself is analog, but it's digitally
generated
up to the final stages) Also, the code itself is a digital code.

In any digital circuit there's lots's of squarewaves that make a nice
harmonics, that splatter all over the radio frequency spectrum. Crappier
AM radios, (like most of them) have poor shielding and discrimination
circuits and can easily pick this electrical noise up. But, it is highly
dependent
on proximity and sensitivity since these harmonics don't have a lot of
radiated energy behind them.

The test I outlined wasn't one that actually tested if a signal is present,
but
merely that the circuity in the fob was getting power, and actually doing
something.

If you put your AM radio on top of a computer, monitor, or any other digital
electronic device you would hear the same electrical noise - assuming the
radio is sensitive enough to pick it up. It may not be. Or it may have
noise
rejection circuitry that filters it out. Or it may be in a huge empty case
that
gives many inches of empty air between the AM radio antenna and the case
wall which would limit the proximity and signal pickup.

Per FCC specs, digital circuits aren't supposed to radiate a lot of energy
anyway -
as it causes intereference - so the manufacturers do what they can to
attempt
to limit it. That is why most computer cases are metal, and the ones that
are plastic
usually are spraypainted with a metallic silver on the inside of the case,
since
computers are terrible emitters of interference. I would be very surprised
if a
car keyfob which is designed for intermittent use only, would have any real
shielding in it.


Ted

In article >,
"Ted Mittelstaedt" > wrote:

> I would be very surprised
> if a
> car keyfob which is designed for intermittent use only, would have any real
> shielding in it.

So would I Ted.
Must be too good a (Sony) radio I used, I'll try a lower quality radio.
I thought you'd tried what you suggested and knew a possible frequency.
BTW, I'm an electronics engineer who knows about radios, computers, etc.;
your description was good.

On Dec 4, 9:36*pm, Josh S > wrote:

BTW, I'm an electronics engineer who knows about radios, computers,
etc.; *your description was good.

Josh and Ted, this should interest you.

http://www.remcom.com/varipose/varip...ess-entry.html

"Pete E. Kruzer" > wrote in message
...
On Dec 4, 9:36 pm, Josh S > wrote:

>>BTW, I'm an electronics engineer who knows about radios, computers,
>>etc.; your description was good.

>Josh and Ted, this should interest you.

>http://www.remcom.com/varipose/varip...ess-entry.html

Hmm, I wonder if it works on cell phones too...

I do fault the analysis, however as they failed to take into account
the enhanced radiation pattern of a female "built like a brick ****house"
I would think the additional surface area and positioning of the,
er, "features" on the chest area would focus and concentrate the beam.

In addition they should have tried other positions than the chin - for
example the calves, thighs, and groin - if you shoved the remote down
your pants how much is the radiation pattern enhanced?

Ted

Ted Mittelstaedt wrote:
> "Pete E. Kruzer" > wrote in message
> ...
> On Dec 4, 9:36 pm, Josh S > wrote:
>
>>> BTW, I'm an electronics engineer who knows about radios, computers,
>>> etc.; your description was good.
>
>> Josh and Ted, this should interest you.
>
>> http://www.remcom.com/varipose/varip...ess-entry.html
>
> Hmm, I wonder if it works on cell phones too...
>
> I do fault the analysis, however as they failed to take into account
> the enhanced radiation pattern of a female "built like a brick ****house"
> I would think the additional surface area and positioning of the,
> er, "features" on the chest area would focus and concentrate the beam.
>
> In addition they should have tried other positions than the chin - for
> example the calves, thighs, and groin - if you shoved the remote down
> your pants how much is the radiation pattern enhanced?
>
> Ted

Depends.

--
Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')