I used to have a in-car cell phone system and it had a glass-mount
antenna which didn't require drilling. Basically, there was
coax(conntected to the cell) to a plate that stuck to the inside of the
rear window. Then on the outside of that window was another plate with
the antenna attached to it. You can buy these a radio shack I noticed.
I've also seem the same done for XM/Sirius Satellite radio.

I have searched and searched and so far have not found the same thing
for 2.4 ghz wifi. Does anyone know where I can find one? If not,
could it be as simple as removing the cell antenna from the exterior
plate(of the radio shack cellular version) and reattaching a 2.4 ghz
omni? Or maybe I could modify the existing cell antenna to the correct
1/2 wavelength of 2.4ghz?

Your suggestions / help / tips are appreciated.

-Kevin

On 10 Jan 2006 20:01:17 -0800, "kevincw01" wrote:

I used to have a in-car cell phone system and it had a glass-mount
antenna which didn't require drilling. Basically, there was
coax(conntected to the cell) to a plate that stuck to the inside of the
rear window. Then on the outside of that window was another plate with
the antenna attached to it. You can buy these a radio shack I noticed.
I've also seem the same done for XM/Sirius Satellite radio.

I have searched and searched and so far have not found the same thing
for 2.4 ghz wifi. Does anyone know where I can find one? If not,
could it be as simple as removing the cell antenna from the exterior
plate(of the radio shack cellular version) and reattaching a 2.4 ghz
omni? Or maybe I could modify the existing cell antenna to the correct
1/2 wavelength of 2.4ghz?

Haven't seen a 2.4G unit, which doesn't mean they aren't out there.

But the through-glass coupling is fairly narrowband and incorporates tuning
elements. The 800/900 MHz units would present a shocking SWR at 2.4G.

sorry to have to ask but what is SWR? My guess is sound to [somthing]
ratio?

On 10 Jan 2006 23:57:15 -0800, "kevincw01" wrote:

sorry to have to ask but what is SWR? My guess is sound to [somthing]
ratio?

Standing wave ratio. It is a measure of how well (in this case) the antenna
system accepts the energy sent to it up the transmission line and radiates it,
compared to reflecting it back to the source transmitter. The transmission line
should be 50 ohm coax in your case. If the tranmission line/system has serious
impedance variation or discontinuity, power is reflected back to the source
rather than passing along the line.

As the through-glass coupling system employs frequency-sensitive tuned circuit
elements, a substantial change in frequency as you suggest will certainly create
a serious impedance discontinuity. Overall transmission efficiency pooter-
antenna would be very poor as a result. You may well find that a decent 2.4G
antenna on the pooter inside the vehicle is more efficient.

looks like i will have to go that route then since I have (so far) not
come across anything for the 2.4G frequency. Either that or drill a
whole in the vehicle.

In article .com,
says...

sorry to have to ask but what is SWR? My guess is sound to [somthing]
ratio?

Oh dear... Someone didn't pay attention in license class...

SWR = Standing Wave Ratio. Put simply, it has to do with how good
of a load the antenna presents to the transmitter, and how efficiently
it will couple the transmitter's energy to the atmosphere.

It needs to be as close to 1:1 as possible. If you're using a
wattmeter to measure things, you want to see as low as possible a
reading in the 'reflected' mode and as high as possible in the
'forward' mode.

Here are some more details.

http://www.hamquick.com/tutorial_index.php?id=20

Happy tweaking.



--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute.
(Known to some as Bruce Lane, ARS KC7GR,
kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com
"If Salvador Dali had owned a computer, would it have been equipped
with surreal ports?"

i have an excused, i dont have a license

In article . com,
says...

i have an excused, i dont have a license

Well, hurry up and get one then, silly person!

Quick, now! Run and pick up a copy of the ARRL's "Now You're
Talking!" or I shall have to taunt you again!

Seriously, hamateur radio's a fun hobby, and it gives you an
excuse to learn all kinds of neat things about electronics in general,
and how it applies to radio in particular.

Keep the peace(es).


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute.
(Known to some as Bruce Lane, ARS KC7GR,
kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com
"If Salvador Dali had owned a computer, would it have been equipped
with surreal ports?"

On Wed, 11 Jan 2006 22:33:28 -0800, Dr. Anton T. Squeegee
wrote:

In article .com,
says...

sorry to have to ask but what is SWR? My guess is sound to [somthing]
ratio?

Oh dear... Someone didn't pay attention in license class...

SWR = Standing Wave Ratio. Put simply, it has to do with how good
of a load the antenna presents to the transmitter, and how efficiently
it will couple the transmitter's energy to the atmosphere.

Nothing to do with coupling the Tx energy to the "atmosphere". Terminating the
line in a resistor of the line's charactertistic impedance will present a nice
SWR and radiate very little.

In article ,
says...

Nothing to do with coupling the Tx energy to the "atmosphere". Terminating the
line in a resistor of the line's charactertistic impedance will present a nice
SWR and radiate very little.

I beg to differ, and I would invite you to think further on this
topic.

An antenna is a coupling device. Its purpose is to efficiently
"couple" or radiate your signal into another transmission medium (open
space, including our atmosphere).

The antenna (effectively an inductor) needs to be resonant at your
operating frequency of choice. It seems to me that the density and
composition of the transmission medium you're coupling to has an effect
on any antenna's resonant frequency.

This, to my understanding, means that an antenna designed for use
in open air will not work underwater, nor will, say, a VLF antenna
designed for submarine usage work in open air.

If you believe I'm misunderstanding, then please point me to some
documentation on the subject, and I will cheerfully STFU.

Keep the peace(es).


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute.
(Known to some as Bruce Lane, ARS KC7GR,
kyrrin (a/t) bluefeathertech[d=o=t]calm -- www.bluefeathertech.com
"If Salvador Dali had owned a computer, would it have been equipped
with surreal ports?"