Carkit: external antenna??

[Anonymous]

Hi all,

I am planning to modify an existing handsfree set for use with my XDA and during planning I found:

http://www.cheap.de/shop/pd1044621724.htm?categoryId=8

On this page you will see the following line:
Anschlussmöglichkeit für externe Antenne
For those that can't understand German: Can support external antenna

How do they do this? I have not found any reference of a connector for an external antenna.

Regards Robert

6 foot tall ape descendant

[Anonymous]

:x :x bummer, this was posted by me but I wasn't logged in :x :x

Climber, Robert

6 foot tall ape descendant

[Carlos]

It probably uses a passive coupler. If you place a properly-designed coil very close to the phone antenna it will couple RF effectively.

[FVH]

Got the car kit yesterday. Opened the cradle and found a large piece of PCB that is positioned close to the antenna of the XDA. This PCB is connected to the lead that comes from the external antenna.

Francois

[Carlos]

Yeah, a passive coupler. Makes sense. It should give you a 3-5dB boost, good enough to clean up conversations in fringe areas.

[Supergrobie]

Sorry,

whats PCB??? :oops:
Can U make a Photo?

Stevie

[FVH]

PCB = Printed Circuit Board.

A foto would be overkill, just imagine a piece of epoxy 5*5 centimeters, covered with copper.

Francois

[wolo]

Hello FVH,

would be nice to hear your experiences with the car-kit.

Does radio mute work ?
Does the sound work through the radio speakers ?
What is in the box of the car-kit ?
Is it worth the money ?

Thanks :lol:

[derekcfoley]

FVH,

Re the PCB description, is it just as you say "a flat piece of copper" without a pcb design on it, if it does what does it look like... are there any other components on it?

e.g. can we make one up easily!
using sticky back plastic or veroboard - e.g. Blue Peter with a bit of Maplin thrown in to achieve a better xda signal...

So if this thing really is just a flat plate, and has no intrinsic components, pcb tracks or special properties...does it that mean we could just rig up a sheet of tinfoil or other conductive item nearby...

I guess we need a Radio Ham with an xda to tell us we're onto a lost cause - Hopefully owning an xda is not like the early days of broadband, where you have to base your homebuying/renting on where you can get a service!

Or someone who's tried out the inductive antenna as mentioned on the other thread http://www.xda-developers.com/forum/viewtopic.php?t=620&start=0&postdays=0&postorder=asc&highlight=antenna

http://www.expansys.us/product.asp?code=AXF-15S

[Peter Poelman]

You can make a perfectly tuned antenna/pickup out of just copper etching on a piece of PCB. Unfortunately, it is infinitely easier to create a distuned antenna from the same components.

[derekcfoley]

After a lot of research it seems the "as seen on TV" signal booster widgets (small PCBs) as suspected dont work.
http://www.bettercalls.com/
http://cellphones-accessories.com/cell-accessories/celphonpow24.html

This is a brilliant site where I found all the info:
http://www.criterioncellular.com/html/reception.html

Whats needed is either:
1) someone making a replacement antenna - as from the internal images shown on this website, it seems fairly easy to remove when dismantling the xda. Why not have a replacement one with an external FME antenna connector. This could then be attached to a small car type antenna.
http://www.tdc.co.uk/antennas/antenna_gsm.htm
apologies if my theories are a little optimistic on this... its just an idea.

2) Purchase of an external signal booster, which can be attached to a small antenna. Then directly plugged into a modified antenna (as 1 above)

3) A seperate re-radiator to boost the outdoor GSM signal inside the home, although this seems expensive! ($279)http://www.criterioncellular.com/html/cellular-amplifier-bda.html

4) as carlos suggested an inductive repeater, you can buy these for GPS systems, why not for GSM signals?http://www.expansys.com/product.asp?code=GPSW-RRAD-45

FVH - Have you noticed any difference with signal using the inductive coupler?
:wink: [/b]