RF Amplifier Questions

[eckcotech]

Hey all,

I am currently experimenting with Digi's Xbee Pro 900mhz RF chips and I would like to look into creating an rf amplifier to boost the output. at 4' off the ground with clear line of sight, these chips are still only realizing about 1000' range.

I have done some small projects with pics and am familiar with the digi chips but I have no real experience with RF and I am not sure where to start.

What I would like to create is a small circuit that I could add to my existing xbee project to boost the output signal by 20-40db or more.

any advice or info on where to start figuring out what would be required for this kind of circuit would be greatly appreciated.

 

[jiripolivka]

While you can try to boost the RF power b y adding an amplifier, you can extend the range by improving the antenna.
At 900 MHz, the easiest is to add a dipole with a corner or parabolic reflector made of a perforated sheet. You can add a similar antenna to the other end of your link. You can also try a small Yagi antenna.
Experimenting with antennas can improve your link easier than buffering one transmitter.

 

[davenn]

You should also realise from a legal point of view, that band allocation is supposed to be low power short range so as not to interfer with licenced users of the band

Dave