I just got a GPS module (superstar). The annoying thing about it is the antenna. What is so special about a GPS antenna?

It has about 5cm of wire(too shoort). The guy who gave it to me said that it couldn't be longer without being amplified.

Can i make my own antenna for a GPS receiver that is more suitable for my project?

 

GPS is a high frequency operation. the higher the frequency, the shorter the antenna. the antenna is ther for a reason.

wut the guy probably meant by "amplifying" was to match the impedances. you may be right, that you could get better reception w/ a longer antenna (im not sure of the frequency of GPS, and therefore how long an ideal antenna would be) but it would be pretty hard for you to re-match the impedances.

BTW, wut is your project?

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I'm no electronics god, i just talk too much.

 

It is a patch type antenna made from double sided pcb, but with a high dielectric constant to enable the reduction in physical size of the antenna.

The signal level received from a GPS satellite is around -126dBm at 1575 MHz for a good signal. Many GPS antenna's will have a pre-amp in it to amplify the signal before more noise gets picked up in the cable from the antenna to the receiver.

You can try. http://home.iae.nl/users/plundahl/antenne/patchant.htm
Notice that the size is already much bigger than the commercial units using ceramic for the dielectric. This person attempted to get a smaller size by using air as a insulator between the two layers. The connection point of the coax is also very critical to get the correct impedance match.

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

I don't really need to get the antenna smaller. But the problem with it is that it requires quite much "free sight" to the sky. I don't know, maybe all GPS are the same. It does not work indoors. Not even inside(beside) the window. I have to be outside to use it. Is this common for all GPS receivers. Would it be possible to change this whith a better antenna?

As you can see, i am very new to GPS receivers :wink:

 

And by the way. How many sats is recomended to get a rather acurate result? I had 5-6 when i tested it today in the car with the antenna by the front window.

 

You need three satellites for a fix if you know the altitude. Otherwise you need four.