Increasing RFID Card Reader Range


I have a question about the Parallax Serial RFID Card Reader.
Is there a way to increase the range at which it can read tags?
Maybe with a bigger antenna or more power?
A maximum distance of 20cm is a little short for my project.

Any other RFID reader with longer range I found are way to expensive...

I'm happy with any kind of suggestions.

cheers, rob

The only way to do this is to have a larger coil but there is a limit to how far you can go. Probably up to 3' is the maximum. You will also need to re tune the coil to bring it back on resonance.

You can't up the power, one cos it's illegal and two because it is very difficult to do without upsetting things.

illegal! I didn't think about that.

I will try a larger coil.
If I have any success i'll post them here.